[PATCH 00/18] Sequencer for inclusion v4

[PATCH 00/18] Sequencer for inclusion v4

[Ramkumar Ramachandra]

Hi,

There were more style nits pointed out in v3: I learnt my lesson and
ran checkpatch.pl this time.  Apart these minor stylistic changes, the
other changes are:
1. Minor improvements to commit messages.
2. Tests now cleanup first, so one failing test doesn't take
everything else down.
3. A rebase that moves "revert: Propogate errors upwards from
do_pick_commit" to the end of the series.  A big thanks to Jonathan
for performing the rebase for me.

Thanks for reading.

-- Ram

Ramkumar Ramachandra (18):
  advice: Introduce error_resolve_conflict
  config: Introduce functions to write non-standard file
  revert: Simplify and inline add_message_to_msg
  revert: Don't check lone argument in get_encoding
  revert: Rename no_replay to record_origin
  revert: Eliminate global "commit" variable
  revert: Introduce struct to keep command-line options
  revert: Separate cmdline parsing from functional code
  revert: Don't create invalid replay_opts in parse_args
  revert: Save data for continuing after conflict resolution
  revert: Save command-line options for continuing operation
  revert: Make pick_commits functionally act on a commit list
  revert: Introduce --reset to remove sequencer state
  reset: Make reset remove the sequencer state
  revert: Remove sequencer state when no commits are pending
  revert: Don't implictly stomp pending sequencer operation
  revert: Introduce --continue to continue the operation
  revert: Propogate errors upwards from do_pick_commit

 Documentation/git-cherry-pick.txt |    6 +
 Documentation/git-revert.txt      |    6 +
 Documentation/sequencer.txt       |    9 +
 Makefile                          |    2 +
 advice.c                          |   31 ++-
 advice.h                          |    3 +-
 branch.c                          |    2 +
 builtin/revert.c                  |  736 +++++++++++++++++++++++++++++--------
 cache.h                           |    2 +
 config.c                          |   36 ++-
 sequencer.c                       |   19 +
 sequencer.h                       |   20 +
 t/7106-reset-sequence.sh          |   43 +++
 t/t3510-cherry-pick-sequence.sh   |  225 +++++++++++
 14 files changed, 969 insertions(+), 171 deletions(-)
 create mode 100644 Documentation/sequencer.txt
 create mode 100644 sequencer.c
 create mode 100644 sequencer.h
 create mode 100755 t/7106-reset-sequence.sh
 create mode 100755 t/t3510-cherry-pick-sequence.sh

-- 
1.7.4.rc1.7.g2cf08.dirty

[PATCH 01/18] advice: Introduce error_resolve_conflict

[Ramkumar Ramachandra]

Enable future callers to report a conflict and not die immediately by
introducing a new function called error_resolve_conflict.
Re-implement die_resolve_conflict as a call to error_resolve_conflict
followed by a call to die.  Consequently, the message printed by
die_resolve_conflict changes from

  fatal: 'commit' is not possible because you have unmerged files.
         Please, fix them up in the work tree ...
         ...

to

  error: 'commit' is not possible because you have unmerged files.
  hint: Fix them up in the work tree ...
  hint: ...
  fatal: Exiting because of an unresolved conflict.

Hints are printed using the same advise function introduced in
v1.7.3-rc0~26^2~3 (Introduce advise() to print hints, 2010-08-11).

Inspired-by: Christian Couder <chistian.couder@gmail.com>
Helped-by: Jonathan Nieder <jrnieder@gmail.com>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
---
 advice.c         |   31 ++++++++++++++++++++++++-------
 advice.h         |    3 ++-
 builtin/revert.c |    9 ---------
 3 files changed, 26 insertions(+), 17 deletions(-)

diff --git a/advice.c b/advice.c
index 0be4b5f..e02e632 100644
--- a/advice.c
+++ b/advice.c
@@ -19,6 +19,15 @@ static struct {
 	{ "detachedhead", &advice_detached_head },
 };
 
+void advise(const char *advice, ...)
+{
+	va_list params;
+
+	va_start(params, advice);
+	vreportf("hint: ", advice, params);
+	va_end(params);
+}
+
 int git_default_advice_config(const char *var, const char *value)
 {
 	const char *k = skip_prefix(var, "advice.");
@@ -34,16 +43,24 @@ int git_default_advice_config(const char *var, const char *value)
 	return 0;
 }
 
-void NORETURN die_resolve_conflict(const char *me)
+int error_resolve_conflict(const char *me)
 {
-	if (advice_resolve_conflict)
+	error("'%s' is not possible because you have unmerged files.", me);
+	if (advice_resolve_conflict) {
 		/*
 		 * Message used both when 'git commit' fails and when
 		 * other commands doing a merge do.
 		 */
-		die("'%s' is not possible because you have unmerged files.\n"
-		    "Please, fix them up in the work tree, and then use 'git add/rm <file>' as\n"
-		    "appropriate to mark resolution and make a commit, or use 'git commit -a'.", me);
-	else
-		die("'%s' is not possible because you have unmerged files.", me);
+		advise("Fix them up in the work tree,");
+		advise("and then use 'git add/rm <file>' as");
+		advise("appropriate to mark resolution and make a commit,");
+		advise("or use 'git commit -a'.");
+	}
+	return -1;
+}
+
+void NORETURN die_resolve_conflict(const char *me)
+{
+	error_resolve_conflict(me);
+	die("Exiting because of an unresolved conflict.");
 }
diff --git a/advice.h b/advice.h
index 3244ebb..e5d0af7 100644
--- a/advice.h
+++ b/advice.h
@@ -11,7 +11,8 @@ extern int advice_implicit_identity;
 extern int advice_detached_head;
 
 int git_default_advice_config(const char *var, const char *value);
-
+void advise(const char *advice, ...);
+int error_resolve_conflict(const char *me);
 extern void NORETURN die_resolve_conflict(const char *me);
 
 #endif /* ADVICE_H */
diff --git a/builtin/revert.c b/builtin/revert.c
index 1f27c63..2df3f3b 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -214,15 +214,6 @@ static void write_cherry_pick_head(void)
 	strbuf_release(&buf);
 }
 
-static void advise(const char *advice, ...)
-{
-	va_list params;
-
-	va_start(params, advice);
-	vreportf("hint: ", advice, params);
-	va_end(params);
-}
-
 static void print_advice(void)
 {
 	char *msg = getenv("GIT_CHERRY_PICK_HELP");
-- 
1.7.4.rc1.7.g2cf08.dirty

[PATCH 02/18] config: Introduce functions to write non-standard file

[Ramkumar Ramachandra]

Introduce two new functions corresponding to "git_config_set" and
"git_config_set_multivar" to write a non-standard configuration file.
Expose thse new functions in cache.h for other git programs to use.

Helped-by: Jeff King <peff@peff.net>
Helped-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
---
 cache.h  |    2 ++
 config.c |   36 +++++++++++++++++++++++++++---------
 2 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/cache.h b/cache.h
index 9e12d55..33d3428 100644
--- a/cache.h
+++ b/cache.h
@@ -1069,9 +1069,11 @@ extern int git_config_bool(const char *, const char *);
 extern int git_config_maybe_bool(const char *, const char *);
 extern int git_config_string(const char **, const char *, const char *);
 extern int git_config_pathname(const char **, const char *, const char *);
+extern int git_config_set_in_file(const char *, const char *, const char *);
 extern int git_config_set(const char *, const char *);
 extern int git_config_parse_key(const char *, char **, int *);
 extern int git_config_set_multivar(const char *, const char *, const char *, int);
+extern int git_config_set_multivar_in_file(const char *, const char *, const char *, const char *, int);
 extern int git_config_rename_section(const char *, const char *);
 extern const char *git_etc_gitconfig(void);
 extern int check_repository_format_version(const char *var, const char *value, void *cb);
diff --git a/config.c b/config.c
index e42c59b..9e8580b 100644
--- a/config.c
+++ b/config.c
@@ -1092,6 +1092,12 @@ contline:
 	return offset;
 }
 
+int git_config_set_in_file(const char *config_filename,
+			const char *key, const char *value)
+{
+	return git_config_set_multivar_in_file(config_filename, key, value, NULL, 0);
+}
+
 int git_config_set(const char *key, const char *value)
 {
 	return git_config_set_multivar(key, value, NULL, 0);
@@ -1189,19 +1195,14 @@ out_free_ret_1:
  * - the config file is removed and the lock file rename()d to it.
  *
  */
-int git_config_set_multivar(const char *key, const char *value,
-	const char *value_regex, int multi_replace)
+int git_config_set_multivar_in_file(const char *config_filename,
+				const char *key, const char *value,
+				const char *value_regex, int multi_replace)
 {
 	int fd = -1, in_fd;
 	int ret;
-	char *config_filename;
 	struct lock_file *lock = NULL;
 
-	if (config_exclusive_filename)
-		config_filename = xstrdup(config_exclusive_filename);
-	else
-		config_filename = git_pathdup("config");
-
 	/* parse-key returns negative; flip the sign to feed exit(3) */
 	ret = 0 - git_config_parse_key(key, &store.key, &store.baselen);
 	if (ret)
@@ -1378,7 +1379,6 @@ int git_config_set_multivar(const char *key, const char *value,
 out_free:
 	if (lock)
 		rollback_lock_file(lock);
-	free(config_filename);
 	return ret;
 
 write_err_out:
@@ -1387,6 +1387,24 @@ write_err_out:
 
 }
 
+int git_config_set_multivar(const char *key, const char *value,
+			const char *value_regex, int multi_replace)
+{
+	const char *config_filename;
+	char *buf = NULL;
+	int ret;
+
+	if (config_exclusive_filename)
+		config_filename = config_exclusive_filename;
+	else
+		config_filename = buf = git_pathdup("config");
+
+	ret = git_config_set_multivar_in_file(config_filename, key, value,
+					value_regex, multi_replace);
+	free(buf);
+	return ret;
+}
+
 static int section_name_match (const char *buf, const char *name)
 {
 	int i = 0, j = 0, dot = 0;
-- 
1.7.4.rc1.7.g2cf08.dirty

Re: [PATCH 02/18] config: Introduce functions to write non-standard file

[Jonathan Nieder]

Ramkumar Ramachandra wrote:

> Expose thse new functions in cache.h for other git programs to use.

s/thse/these/

Other messages need a spell-check, too.  Aside from that, patches 1-3
look good --- thanks for your perseverance.

Re: [PATCH 02/18] config: Introduce functions to write non-standard file

[Ramkumar Ramachandra]

Hi,

Jonathan Nieder writes:
> Other messages need a spell-check, too.  Aside from that, patches 1-3
> look good --- thanks for your perseverance.

Fixed all.  Also hooked flyspell to git-commit-mode to avoid this in future.

Thanks.

-- Ram

[PATCH 03/18] revert: Simplify and inline add_message_to_msg

[Ramkumar Ramachandra]

The add_message_to_msg function has some dead code, an unclear API,
only one callsite.  While it originally intended fill up an empty
commit message with the commit object name while picking, it really
doesn't do this -- a bug introduced in v1.5.1-rc1~65^2~2 (Make
git-revert & git-cherry-pick a builtin, 2007-03-01).  Today, tests in
t3505-cherry-pick-empty.sh indicate that not filling up an empty
commit message is the desired behavior.  Re-implement and inline the
function accordingly, with a benefecial side-effect: don't dereference
a NULL pointer when the commit doesn't have a delimeter after the
header.

Helped-by: Junio C Hamano <gitster@pobox.com>
Mentored-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
---
 builtin/revert.c |   28 ++++++++++++++--------------
 1 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/builtin/revert.c b/builtin/revert.c
index 2df3f3b..7dfe295 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -185,19 +185,6 @@ static char *get_encoding(const char *message)
 	return NULL;
 }
 
-static void add_message_to_msg(struct strbuf *msgbuf, const char *message)
-{
-	const char *p = message;
-	while (*p && (*p != '\n' || p[1] != '\n'))
-		p++;
-
-	if (!*p)
-		strbuf_addstr(msgbuf, sha1_to_hex(commit->object.sha1));
-
-	p += 2;
-	strbuf_addstr(msgbuf, p);
-}
-
 static void write_cherry_pick_head(void)
 {
 	int fd;
@@ -462,11 +449,24 @@ static int do_pick_commit(void)
 		}
 		strbuf_addstr(&msgbuf, ".\n");
 	} else {
+		const char *p;
+
 		base = parent;
 		base_label = msg.parent_label;
 		next = commit;
 		next_label = msg.label;
-		add_message_to_msg(&msgbuf, msg.message);
+
+		/*
+		 * Append the commit log message to msgbuf; it starts
+		 * after the tree, parent, author, committer
+		 * information followed by "\n\n".
+		 */
+		p = strstr(msg.message, "\n\n");
+		if (p) {
+			p += 2;
+			strbuf_addstr(&msgbuf, p);
+		}
+
 		if (no_replay) {
 			strbuf_addstr(&msgbuf, "(cherry picked from commit ");
 			strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
-- 
1.7.4.rc1.7.g2cf08.dirty

[PATCH 04/18] revert: Don't check lone argument in get_encoding

[Ramkumar Ramachandra]

The only place get_encoding uses the global "commit" variable is when
writing an error message explaining that its lone argument was NULL.
Since the function's only caller ensures that a NULL argument isn't
passed, we can remove this check wtih two beneficial consequences:

1. Since the function doesn't use the global "commit" variable any
   more, it won't need to change when we eliminate the global variable
   later in the series.
2. Translators no longer need to localize an error message that'll
   never be shown.

Suggested-by: Junio C Hamano <gitster@pobox.com>
Mentored-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
---
 builtin/revert.c |    3 ---
 1 files changed, 0 insertions(+), 3 deletions(-)

diff --git a/builtin/revert.c b/builtin/revert.c
index 7dfe295..30b39c0 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -167,9 +167,6 @@ static char *get_encoding(const char *message)
 {
 	const char *p = message, *eol;
 
-	if (!p)
-		die (_("Could not read commit message of %s"),
-				sha1_to_hex(commit->object.sha1));
 	while (*p && *p != '\n') {
 		for (eol = p + 1; *eol && *eol != '\n'; eol++)
 			; /* do nothing */
-- 
1.7.4.rc1.7.g2cf08.dirty

[PATCH 05/18] revert: Rename no_replay to record_origin

[Ramkumar Ramachandra]

The "-x" command-line option is used to record the name of the
original commits being picked in the commit message.  The variable
corresponding to this option is named "no_replay" for historical
reasons; the name is especially confusing because the term "replay" is
used to describe what cherry-pick does (for example, in the
documentation of the "--mainline" option).  So, give the variable
corresponding to the "-x" command-line option a better name:
"record_origin".

Mentored-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
---
 builtin/revert.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/builtin/revert.c b/builtin/revert.c
index 30b39c0..794c050 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -35,7 +35,7 @@ static const char * const cherry_pick_usage[] = {
 	NULL
 };
 
-static int edit, no_replay, no_commit, mainline, signoff, allow_ff;
+static int edit, record_origin, no_commit, mainline, signoff, allow_ff;
 static enum { REVERT, CHERRY_PICK } action;
 static struct commit *commit;
 static int commit_argc;
@@ -91,7 +91,7 @@ static void parse_args(int argc, const char **argv)
 
 	if (action == CHERRY_PICK) {
 		struct option cp_extra[] = {
-			OPT_BOOLEAN('x', NULL, &no_replay, "append commit name"),
+			OPT_BOOLEAN('x', NULL, &record_origin, "append commit name"),
 			OPT_BOOLEAN(0, "ff", &allow_ff, "allow fast-forward"),
 			OPT_END(),
 		};
@@ -464,7 +464,7 @@ static int do_pick_commit(void)
 			strbuf_addstr(&msgbuf, p);
 		}
 
-		if (no_replay) {
+		if (record_origin) {
 			strbuf_addstr(&msgbuf, "(cherry picked from commit ");
 			strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 			strbuf_addstr(&msgbuf, ")\n");
@@ -559,7 +559,7 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 			die(_("cherry-pick --ff cannot be used with --signoff"));
 		if (no_commit)
 			die(_("cherry-pick --ff cannot be used with --no-commit"));
-		if (no_replay)
+		if (record_origin)
 			die(_("cherry-pick --ff cannot be used with -x"));
 		if (edit)
 			die(_("cherry-pick --ff cannot be used with --edit"));
-- 
1.7.4.rc1.7.g2cf08.dirty

[PATCH 06/18] revert: Eliminate global "commit" variable

[Ramkumar Ramachandra]

Functions which act on commits currently rely on a file-scope static
variable to be set before they're called.  Consequently, the API and
corresponding callsites are ugly and unclear.  Remove this variable
and change their API to accept the commit to act on as additional
argument so that the callsites change from looking like

  commit = prepare_a_commit();
  act_on_commit();

to looking like

  commit = prepare_a_commit();
  act_on_commit(commit);

This change is also in line with our long-term goal of exposing some
of these functions through a public API.

Inspired-by: Christian Couder <chriscool@tuxfamily.org>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/revert.c |   22 +++++++++++-----------
 1 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/builtin/revert.c b/builtin/revert.c
index 794c050..d6c9f1d 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -37,7 +37,6 @@ static const char * const cherry_pick_usage[] = {
 
 static int edit, record_origin, no_commit, mainline, signoff, allow_ff;
 static enum { REVERT, CHERRY_PICK } action;
-static struct commit *commit;
 static int commit_argc;
 static const char **commit_argv;
 static int allow_rerere_auto;
@@ -116,25 +115,25 @@ struct commit_message {
 	const char *message;
 };
 
-static int get_message(const char *raw_message, struct commit_message *out)
+static int get_message(struct commit *commit, struct commit_message *out)
 {
 	const char *encoding;
 	const char *abbrev, *subject;
 	int abbrev_len, subject_len;
 	char *q;
 
-	if (!raw_message)
+	if (!commit->buffer)
 		return -1;
-	encoding = get_encoding(raw_message);
+	encoding = get_encoding(commit->buffer);
 	if (!encoding)
 		encoding = "UTF-8";
 	if (!git_commit_encoding)
 		git_commit_encoding = "UTF-8";
 
 	out->reencoded_message = NULL;
-	out->message = raw_message;
+	out->message = commit->buffer;
 	if (strcmp(encoding, git_commit_encoding))
-		out->reencoded_message = reencode_string(raw_message,
+		out->reencoded_message = reencode_string(commit->buffer,
 					git_commit_encoding, encoding);
 	if (out->reencoded_message)
 		out->message = out->reencoded_message;
@@ -182,7 +181,7 @@ static char *get_encoding(const char *message)
 	return NULL;
 }
 
-static void write_cherry_pick_head(void)
+static void write_cherry_pick_head(struct commit *commit)
 {
 	int fd;
 	struct strbuf buf = STRBUF_INIT;
@@ -355,7 +354,7 @@ static int run_git_commit(const char *defmsg)
 	return run_command_v_opt(args, RUN_GIT_CMD);
 }
 
-static int do_pick_commit(void)
+static int do_pick_commit(struct commit *commit)
 {
 	unsigned char head[20];
 	struct commit *base, *next, *parent;
@@ -417,7 +416,7 @@ static int do_pick_commit(void)
 		die(_("%s: cannot parse parent commit %s"),
 		    me, sha1_to_hex(parent->object.sha1));
 
-	if (get_message(commit->buffer, &msg) != 0)
+	if (get_message(commit, &msg) != 0)
 		die(_("Cannot get commit message for %s"),
 				sha1_to_hex(commit->object.sha1));
 
@@ -470,7 +469,7 @@ static int do_pick_commit(void)
 			strbuf_addstr(&msgbuf, ")\n");
 		}
 		if (!no_commit)
-			write_cherry_pick_head();
+			write_cherry_pick_head(commit);
 	}
 
 	if (!strategy || !strcmp(strategy, "recursive") || action == REVERT) {
@@ -548,6 +547,7 @@ static void read_and_refresh_cache(const char *me)
 static int revert_or_cherry_pick(int argc, const char **argv)
 {
 	struct rev_info revs;
+	struct commit *commit;
 
 	git_config(git_default_config, NULL);
 	me = action == REVERT ? "revert" : "cherry-pick";
@@ -570,7 +570,7 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 	prepare_revs(&revs);
 
 	while ((commit = get_revision(&revs))) {
-		int res = do_pick_commit();
+		int res = do_pick_commit(commit);
 		if (res)
 			return res;
 	}
-- 
1.7.4.rc1.7.g2cf08.dirty

[PATCH 07/18] revert: Introduce struct to keep command-line options

[Ramkumar Ramachandra]

The current code uses a set of file-scope static variables to tell the
cherry-pick/ revert machinery how to replay the changes, and
initializes them by parsing the command-line arguments.  In later
steps in this series, we would like to introduce an API function that
calls into this machinery directly and have a way to tell it what to
do.  Hence, introduce a structure to group these variables, so that
the API can take them as a single replay_options parameter.  The only
exception is the variable "me" -- remove it since it not an
independent option, and can be inferred from the action.

Unfortunately, this patch introduces a minor regression.  Parsing
strategy-option violates a C89 rule: Initializers cannot refer to
variables whose address is not known at compile time.  Currently, this
rule is violated by some other parts of Git as well, and it is
possible to get GCC to report these instances using the "-std=c89
-pedantic" option.

Inspired-by: Christian Couder <chriscool@tuxfamily.org>
Mentored-by: Jonathan Nieder <jrnieder@gmail.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/revert.c |  201 ++++++++++++++++++++++++++++++------------------------
 1 files changed, 113 insertions(+), 88 deletions(-)

diff --git a/builtin/revert.c b/builtin/revert.c
index d6c9f1d..50f72de 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -35,76 +35,94 @@ static const char * const cherry_pick_usage[] = {
 	NULL
 };
 
-static int edit, record_origin, no_commit, mainline, signoff, allow_ff;
-static enum { REVERT, CHERRY_PICK } action;
-static int commit_argc;
-static const char **commit_argv;
-static int allow_rerere_auto;
-
-static const char *me;
-
-/* Merge strategy. */
-static const char *strategy;
-static const char **xopts;
-static size_t xopts_nr, xopts_alloc;
+enum replay_action { REVERT, CHERRY_PICK };
+
+struct replay_opts {
+	enum replay_action action;
+
+	/* Boolean options */
+	int edit;
+	int record_origin;
+	int no_commit;
+	int signoff;
+	int allow_ff;
+	int allow_rerere_auto;
+
+	int mainline;
+	int commit_argc;
+	const char **commit_argv;
+
+	/* Merge strategy */
+	const char *strategy;
+	const char **xopts;
+	size_t xopts_nr, xopts_alloc;
+};
 
 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
 
+static const char *action_name(const struct replay_opts *opts)
+{
+	return opts->action == REVERT ? "revert" : "cherry-pick";
+}
+
 static char *get_encoding(const char *message);
 
-static const char * const *revert_or_cherry_pick_usage(void)
+static const char * const *revert_or_cherry_pick_usage(struct replay_opts *opts)
 {
-	return action == REVERT ? revert_usage : cherry_pick_usage;
+	return opts->action == REVERT ? revert_usage : cherry_pick_usage;
 }
 
 static int option_parse_x(const struct option *opt,
 			  const char *arg, int unset)
 {
+	struct replay_opts **opts_ptr = opt->value;
+	struct replay_opts *opts = *opts_ptr;
+
 	if (unset)
 		return 0;
 
-	ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
-	xopts[xopts_nr++] = xstrdup(arg);
+	ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
+	opts->xopts[opts->xopts_nr++] = xstrdup(arg);
 	return 0;
 }
 
-static void parse_args(int argc, const char **argv)
+static void parse_args(int argc, const char **argv, struct replay_opts *opts)
 {
-	const char * const * usage_str = revert_or_cherry_pick_usage();
+	const char * const * usage_str = revert_or_cherry_pick_usage(opts);
 	int noop;
 	struct option options[] = {
-		OPT_BOOLEAN('n', "no-commit", &no_commit, "don't automatically commit"),
-		OPT_BOOLEAN('e', "edit", &edit, "edit the commit message"),
+		OPT_BOOLEAN('n', "no-commit", &opts->no_commit, "don't automatically commit"),
+		OPT_BOOLEAN('e', "edit", &opts->edit, "edit the commit message"),
 		{ OPTION_BOOLEAN, 'r', NULL, &noop, NULL, "no-op (backward compatibility)",
 		  PARSE_OPT_NOARG | PARSE_OPT_HIDDEN, NULL, 0 },
-		OPT_BOOLEAN('s', "signoff", &signoff, "add Signed-off-by:"),
-		OPT_INTEGER('m', "mainline", &mainline, "parent number"),
-		OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
-		OPT_STRING(0, "strategy", &strategy, "strategy", "merge strategy"),
-		OPT_CALLBACK('X', "strategy-option", &xopts, "option",
+		OPT_BOOLEAN('s', "signoff", &opts->signoff, "add Signed-off-by:"),
+		OPT_INTEGER('m', "mainline", &opts->mainline, "parent number"),
+		OPT_RERERE_AUTOUPDATE(&opts->allow_rerere_auto),
+		OPT_STRING(0, "strategy", &opts->strategy, "strategy", "merge strategy"),
+		OPT_CALLBACK('X', "strategy-option", &opts, "option",
 			"option for merge strategy", option_parse_x),
 		OPT_END(),
 		OPT_END(),
 		OPT_END(),
 	};
 
-	if (action == CHERRY_PICK) {
+	if (opts->action == CHERRY_PICK) {
 		struct option cp_extra[] = {
-			OPT_BOOLEAN('x', NULL, &record_origin, "append commit name"),
-			OPT_BOOLEAN(0, "ff", &allow_ff, "allow fast-forward"),
+			OPT_BOOLEAN('x', NULL, &opts->record_origin, "append commit name"),
+			OPT_BOOLEAN(0, "ff", &opts->allow_ff, "allow fast-forward"),
 			OPT_END(),
 		};
 		if (parse_options_concat(options, ARRAY_SIZE(options), cp_extra))
 			die(_("program error"));
 	}
 
-	commit_argc = parse_options(argc, argv, NULL, options, usage_str,
-				    PARSE_OPT_KEEP_ARGV0 |
-				    PARSE_OPT_KEEP_UNKNOWN);
-	if (commit_argc < 2)
+	opts->commit_argc = parse_options(argc, argv, NULL, options, usage_str,
+					PARSE_OPT_KEEP_ARGV0 |
+					PARSE_OPT_KEEP_UNKNOWN);
+	if (opts->commit_argc < 2)
 		usage_with_options(usage_str, options);
 
-	commit_argv = argv;
+	opts->commit_argv = argv;
 }
 
 struct commit_message {
@@ -240,20 +258,20 @@ static struct tree *empty_tree(void)
 	return tree;
 }
 
-static NORETURN void die_dirty_index(const char *me)
+static NORETURN void die_dirty_index(struct replay_opts *opts)
 {
 	if (read_cache_unmerged()) {
-		die_resolve_conflict(me);
+		die_resolve_conflict(action_name(opts));
 	} else {
 		if (advice_commit_before_merge) {
-			if (action == REVERT)
+			if (opts->action == REVERT)
 				die(_("Your local changes would be overwritten by revert.\n"
 					  "Please, commit your changes or stash them to proceed."));
 			else
 				die(_("Your local changes would be overwritten by cherry-pick.\n"
 					  "Please, commit your changes or stash them to proceed."));
 		} else {
-			if (action == REVERT)
+			if (opts->action == REVERT)
 				die(_("Your local changes would be overwritten by revert.\n"));
 			else
 				die(_("Your local changes would be overwritten by cherry-pick.\n"));
@@ -274,7 +292,8 @@ static int fast_forward_to(const unsigned char *to, const unsigned char *from)
 
 static int do_recursive_merge(struct commit *base, struct commit *next,
 			      const char *base_label, const char *next_label,
-			      unsigned char *head, struct strbuf *msgbuf)
+			      unsigned char *head, struct strbuf *msgbuf,
+			      struct replay_opts *opts)
 {
 	struct merge_options o;
 	struct tree *result, *next_tree, *base_tree, *head_tree;
@@ -295,7 +314,7 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
 	next_tree = next ? next->tree : empty_tree();
 	base_tree = base ? base->tree : empty_tree();
 
-	for (xopt = xopts; xopt != xopts + xopts_nr; xopt++)
+	for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
 		parse_merge_opt(&o, *xopt);
 
 	clean = merge_trees(&o,
@@ -306,7 +325,7 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
 	    (write_cache(index_fd, active_cache, active_nr) ||
 	     commit_locked_index(&index_lock)))
 		/* TRANSLATORS: %s will be "revert" or "cherry-pick" */
-		die(_("%s: Unable to write new index file"), me);
+		die(_("%s: Unable to write new index file"), action_name(opts));
 	rollback_lock_file(&index_lock);
 
 	if (!clean) {
@@ -335,7 +354,7 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
  * If we are revert, or if our cherry-pick results in a hand merge,
  * we had better say that the current user is responsible for that.
  */
-static int run_git_commit(const char *defmsg)
+static int run_git_commit(const char *defmsg, struct replay_opts *opts)
 {
 	/* 6 is max possible length of our args array including NULL */
 	const char *args[6];
@@ -343,9 +362,9 @@ static int run_git_commit(const char *defmsg)
 
 	args[i++] = "commit";
 	args[i++] = "-n";
-	if (signoff)
+	if (opts->signoff)
 		args[i++] = "-s";
-	if (!edit) {
+	if (!opts->edit) {
 		args[i++] = "-F";
 		args[i++] = defmsg;
 	}
@@ -354,7 +373,7 @@ static int run_git_commit(const char *defmsg)
 	return run_command_v_opt(args, RUN_GIT_CMD);
 }
 
-static int do_pick_commit(struct commit *commit)
+static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 {
 	unsigned char head[20];
 	struct commit *base, *next, *parent;
@@ -364,7 +383,7 @@ static int do_pick_commit(struct commit *commit)
 	struct strbuf msgbuf = STRBUF_INIT;
 	int res;
 
-	if (no_commit) {
+	if (opts->no_commit) {
 		/*
 		 * We do not intend to commit immediately.  We just want to
 		 * merge the differences in, so let's compute the tree
@@ -377,7 +396,7 @@ static int do_pick_commit(struct commit *commit)
 		if (get_sha1("HEAD", head))
 			die (_("You do not have a valid HEAD"));
 		if (index_differs_from("HEAD", 0))
-			die_dirty_index(me);
+			die_dirty_index(opts);
 	}
 	discard_cache();
 
@@ -389,32 +408,32 @@ static int do_pick_commit(struct commit *commit)
 		int cnt;
 		struct commit_list *p;
 
-		if (!mainline)
+		if (!opts->mainline)
 			die(_("Commit %s is a merge but no -m option was given."),
 			    sha1_to_hex(commit->object.sha1));
 
 		for (cnt = 1, p = commit->parents;
-		     cnt != mainline && p;
+		     cnt != opts->mainline && p;
 		     cnt++)
 			p = p->next;
-		if (cnt != mainline || !p)
+		if (cnt != opts->mainline || !p)
 			die(_("Commit %s does not have parent %d"),
-			    sha1_to_hex(commit->object.sha1), mainline);
+			    sha1_to_hex(commit->object.sha1), opts->mainline);
 		parent = p->item;
-	} else if (0 < mainline)
+	} else if (0 < opts->mainline)
 		die(_("Mainline was specified but commit %s is not a merge."),
 		    sha1_to_hex(commit->object.sha1));
 	else
 		parent = commit->parents->item;
 
-	if (allow_ff && parent && !hashcmp(parent->object.sha1, head))
+	if (opts->allow_ff && parent && !hashcmp(parent->object.sha1, head))
 		return fast_forward_to(commit->object.sha1, head);
 
 	if (parent && parse_commit(parent) < 0)
 		/* TRANSLATORS: The first %s will be "revert" or
 		   "cherry-pick", the second %s a SHA1 */
 		die(_("%s: cannot parse parent commit %s"),
-		    me, sha1_to_hex(parent->object.sha1));
+		    action_name(opts), sha1_to_hex(parent->object.sha1));
 
 	if (get_message(commit, &msg) != 0)
 		die(_("Cannot get commit message for %s"),
@@ -429,7 +448,7 @@ static int do_pick_commit(struct commit *commit)
 
 	defmsg = git_pathdup("MERGE_MSG");
 
-	if (action == REVERT) {
+	if (opts->action == REVERT) {
 		base = commit;
 		base_label = msg.label;
 		next = parent;
@@ -463,18 +482,18 @@ static int do_pick_commit(struct commit *commit)
 			strbuf_addstr(&msgbuf, p);
 		}
 
-		if (record_origin) {
+		if (opts->record_origin) {
 			strbuf_addstr(&msgbuf, "(cherry picked from commit ");
 			strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 			strbuf_addstr(&msgbuf, ")\n");
 		}
-		if (!no_commit)
+		if (!opts->no_commit)
 			write_cherry_pick_head(commit);
 	}
 
-	if (!strategy || !strcmp(strategy, "recursive") || action == REVERT) {
+	if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REVERT) {
 		res = do_recursive_merge(base, next, base_label, next_label,
-					 head, &msgbuf);
+					 head, &msgbuf, opts);
 		write_message(&msgbuf, defmsg);
 	} else {
 		struct commit_list *common = NULL;
@@ -484,23 +503,23 @@ static int do_pick_commit(struct commit *commit)
 
 		commit_list_insert(base, &common);
 		commit_list_insert(next, &remotes);
-		res = try_merge_command(strategy, xopts_nr, xopts, common,
-					sha1_to_hex(head), remotes);
+		res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
+					common, sha1_to_hex(head), remotes);
 		free_commit_list(common);
 		free_commit_list(remotes);
 	}
 
 	if (res) {
-		error(action == REVERT
+		error(opts->action == REVERT
 		      ? _("could not revert %s... %s")
 		      : _("could not apply %s... %s"),
 		      find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
 		      msg.subject);
 		print_advice();
-		rerere(allow_rerere_auto);
+		rerere(opts->allow_rerere_auto);
 	} else {
-		if (!no_commit)
-			res = run_git_commit(defmsg);
+		if (!opts->no_commit)
+			res = run_git_commit(defmsg, opts);
 	}
 
 	free_message(&msg);
@@ -509,18 +528,18 @@ static int do_pick_commit(struct commit *commit)
 	return res;
 }
 
-static void prepare_revs(struct rev_info *revs)
+static void prepare_revs(struct rev_info *revs, struct replay_opts *opts)
 {
 	int argc;
 
 	init_revisions(revs, NULL);
 	revs->no_walk = 1;
-	if (action != REVERT)
+	if (opts->action != REVERT)
 		revs->reverse = 1;
 
-	argc = setup_revisions(commit_argc, commit_argv, revs, NULL);
+	argc = setup_revisions(opts->commit_argc, opts->commit_argv, revs, NULL);
 	if (argc > 1)
-		usage(*revert_or_cherry_pick_usage());
+		usage(*revert_or_cherry_pick_usage(opts));
 
 	if (prepare_revision_walk(revs))
 		die(_("revision walk setup failed"));
@@ -529,48 +548,48 @@ static void prepare_revs(struct rev_info *revs)
 		die(_("empty commit set passed"));
 }
 
-static void read_and_refresh_cache(const char *me)
+static void read_and_refresh_cache(struct replay_opts *opts)
 {
 	static struct lock_file index_lock;
 	int index_fd = hold_locked_index(&index_lock, 0);
 	if (read_index_preload(&the_index, NULL) < 0)
-		die(_("git %s: failed to read the index"), me);
+		die(_("git %s: failed to read the index"), action_name(opts));
 	refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
 	if (the_index.cache_changed) {
 		if (write_index(&the_index, index_fd) ||
 		    commit_locked_index(&index_lock))
-			die(_("git %s: failed to refresh the index"), me);
+			die(_("git %s: failed to refresh the index"), action_name(opts));
 	}
 	rollback_lock_file(&index_lock);
 }
 
-static int revert_or_cherry_pick(int argc, const char **argv)
+static int revert_or_cherry_pick(int argc, const char **argv,
+				struct replay_opts *opts)
 {
 	struct rev_info revs;
 	struct commit *commit;
 
 	git_config(git_default_config, NULL);
-	me = action == REVERT ? "revert" : "cherry-pick";
-	setenv(GIT_REFLOG_ACTION, me, 0);
-	parse_args(argc, argv);
+	setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
+	parse_args(argc, argv, opts);
 
-	if (allow_ff) {
-		if (signoff)
+	if (opts->allow_ff) {
+		if (opts->signoff)
 			die(_("cherry-pick --ff cannot be used with --signoff"));
-		if (no_commit)
+		if (opts->no_commit)
 			die(_("cherry-pick --ff cannot be used with --no-commit"));
-		if (record_origin)
+		if (opts->record_origin)
 			die(_("cherry-pick --ff cannot be used with -x"));
-		if (edit)
+		if (opts->edit)
 			die(_("cherry-pick --ff cannot be used with --edit"));
 	}
 
-	read_and_refresh_cache(me);
+	read_and_refresh_cache(opts);
 
-	prepare_revs(&revs);
+	prepare_revs(&revs, opts);
 
 	while ((commit = get_revision(&revs))) {
-		int res = do_pick_commit(commit);
+		int res = do_pick_commit(commit, opts);
 		if (res)
 			return res;
 	}
@@ -580,14 +599,20 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 
 int cmd_revert(int argc, const char **argv, const char *prefix)
 {
+	struct replay_opts opts;
+
+	memset(&opts, 0, sizeof(opts));
 	if (isatty(0))
-		edit = 1;
-	action = REVERT;
-	return revert_or_cherry_pick(argc, argv);
+		opts.edit = 1;
+	opts.action = REVERT;
+	return revert_or_cherry_pick(argc, argv, &opts);
 }
 
 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 {
-	action = CHERRY_PICK;
-	return revert_or_cherry_pick(argc, argv);
+	struct replay_opts opts;
+
+	memset(&opts, 0, sizeof(opts));
+	opts.action = CHERRY_PICK;
+	return revert_or_cherry_pick(argc, argv, &opts);
 }
-- 
1.7.4.rc1.7.g2cf08.dirty

[PATCH 08/18] revert: Separate cmdline parsing from functional code

[Ramkumar Ramachandra]

Currently, revert_or_cherry_pick sets up a default git config, parses
command-line arguments, before preparing to pick commits.  This makes
for a bad API as the central worry of callers is to assert whether or
not a conflict occured while cherry picking.  The current API is like:

  if (revert_or_cherry_pick(argc, argv, opts) < 0)
     print "Something failed, we're not sure what"

Simplify and rename revert_or_cherry_pick to pick_commits so that it
only has the responsibility of setting up the revision walker and
picking commits in a loop.  Transfer the remaining work to its
callers.  Now, the API is simplified as:

  if (parse_args(argc, argv, opts) < 0)
     print "Can't parse arguments"
  if (pick_commits(opts) < 0)
     print "Error encountered in picking machinery"

Later in the series, pick_commits will also serve as the starting
point for continuing a cherry-pick or revert.

Inspired-by: Christian Couder <chriscool@tuxfamily.org>
Helped-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/revert.c |   14 +++++++-------
 1 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/builtin/revert.c b/builtin/revert.c
index 50f72de..90fe2ef 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -563,16 +563,12 @@ static void read_and_refresh_cache(struct replay_opts *opts)
 	rollback_lock_file(&index_lock);
 }
 
-static int revert_or_cherry_pick(int argc, const char **argv,
-				struct replay_opts *opts)
+static int pick_commits(struct replay_opts *opts)
 {
 	struct rev_info revs;
 	struct commit *commit;
 
-	git_config(git_default_config, NULL);
 	setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
-	parse_args(argc, argv, opts);
-
 	if (opts->allow_ff) {
 		if (opts->signoff)
 			die(_("cherry-pick --ff cannot be used with --signoff"));
@@ -605,7 +601,9 @@ int cmd_revert(int argc, const char **argv, const char *prefix)
 	if (isatty(0))
 		opts.edit = 1;
 	opts.action = REVERT;
-	return revert_or_cherry_pick(argc, argv, &opts);
+	git_config(git_default_config, NULL);
+	parse_args(argc, argv, &opts);
+	return pick_commits(&opts);
 }
 
 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
@@ -614,5 +612,7 @@ int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 
 	memset(&opts, 0, sizeof(opts));
 	opts.action = CHERRY_PICK;
-	return revert_or_cherry_pick(argc, argv, &opts);
+	git_config(git_default_config, NULL);
+	parse_args(argc, argv, &opts);
+	return pick_commits(&opts);
 }
-- 
1.7.4.rc1.7.g2cf08.dirty

[PATCH 09/18] revert: Don't create invalid replay_opts in parse_args

[Ramkumar Ramachandra]

The "--ff" command-line option cannot be used with some other
command-line options.  However, parse_args still parses these
incompatible options into a replay_opts structure for use by the rest
of the program.  Although pick_commits, the current gatekeeper to the
cherry-pick machinery, checks the validity of the replay_opts
structure before before starting its operation, there will be multiple
entry points to the cherry-pick machinery in future.  To futureproof
the code and catch these errors in one place, make sure that an
invalid replay_opts structure is not created by parse_args in the
first place.  We still check the replay_opts structure for validity in
pick_commits, but this is an assert() now to emphasize that it's the
caller's responsibility to get it right.

Inspired-by: Christian Couder <chriscool@tuxfamily.org>
Mentored-by: Jonathan Nieder <jrnieder@gmail.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/revert.c |   38 +++++++++++++++++++++++++++-----------
 1 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/builtin/revert.c b/builtin/revert.c
index 90fe2ef..9c29852 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -86,9 +86,26 @@ static int option_parse_x(const struct option *opt,
 	return 0;
 }
 
+static void verify_opt_compatible(const char *me, const char *base_opt, ...)
+{
+	const char *this_opt;
+	va_list ap;
+	int set;
+
+	va_start(ap, base_opt);
+	while ((this_opt = va_arg(ap, const char *))) {
+		set = va_arg(ap, int);
+		if (set)
+			die(_("%s: %s cannot be used with %s"),
+				me, this_opt, base_opt);
+	}
+	va_end(ap);
+}
+
 static void parse_args(int argc, const char **argv, struct replay_opts *opts)
 {
 	const char * const * usage_str = revert_or_cherry_pick_usage(opts);
+	const char *me = action_name(opts);
 	int noop;
 	struct option options[] = {
 		OPT_BOOLEAN('n', "no-commit", &opts->no_commit, "don't automatically commit"),
@@ -122,6 +139,13 @@ static void parse_args(int argc, const char **argv, struct replay_opts *opts)
 	if (opts->commit_argc < 2)
 		usage_with_options(usage_str, options);
 
+	if (opts->allow_ff)
+		verify_opt_compatible(me, "--ff",
+				"--signoff", opts->signoff,
+				"--no-commit", opts->no_commit,
+				"-x", opts->record_origin,
+				"--edit", opts->edit,
+				NULL);
 	opts->commit_argv = argv;
 }
 
@@ -569,17 +593,9 @@ static int pick_commits(struct replay_opts *opts)
 	struct commit *commit;
 
 	setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
-	if (opts->allow_ff) {
-		if (opts->signoff)
-			die(_("cherry-pick --ff cannot be used with --signoff"));
-		if (opts->no_commit)
-			die(_("cherry-pick --ff cannot be used with --no-commit"));
-		if (opts->record_origin)
-			die(_("cherry-pick --ff cannot be used with -x"));
-		if (opts->edit)
-			die(_("cherry-pick --ff cannot be used with --edit"));
-	}
-
+	if (opts->allow_ff)
+		assert(!(opts->signoff || opts->no_commit ||
+				opts->record_origin || opts->edit));
 	read_and_refresh_cache(opts);
 
 	prepare_revs(&revs, opts);
-- 
1.7.4.rc1.7.g2cf08.dirty

[PATCH 10/18] revert: Save data for continuing after conflict resolution

[Ramkumar Ramachandra]

Ever since v1.7.2-rc1~4^2~7 (revert: allow cherry-picking more than
one commit, 2010-06-02), a single invocation of "git cherry-pick" or
"git revert" can perform picks of several individual commits.  To
implement features like "--continue" to continue the whole operation,
we will need to store some information about the state and the plan at
the beginning.  Introduce a ".git/sequencer/head" file to store this
state, and ".git/sequencer/todo" file to store the plan.  The head
file contains the SHA-1 of the HEAD before the start of the operation,
and the todo file contains an instruction sheet whose format is
inspired by the format of the "rebase -i" instruction sheet.  As a
result, a typical todo file looks like:

  pick 8537f0e submodule add: test failure when url is not configured
  pick 4d68932 submodule add: allow relative repository path
  pick f22a17e submodule add: clean up duplicated code
  pick 59a5775 make copy_ref globally available

Since SHA-1 hex is abbreviated using an find_unique_abbrev(), it is
unambiguous.  This does not guarantee that there will be no ambiguity
when more objects are added to the repository.

That these two files alone are not enough to implement a "--continue"
that remembers the command-line options specified; later patches in
the series save them too.

These new files are unrelated to the existing .git/CHERRY_PICK_HEAD,
which will still be useful while committing after a conflict
resolution.

Inspired-by: Christian Couder <chriscool@tuxfamily.org>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/revert.c                |  134 +++++++++++++++++++++++++++++++++++++-
 t/t3510-cherry-pick-sequence.sh |   48 ++++++++++++++
 2 files changed, 178 insertions(+), 4 deletions(-)
 create mode 100755 t/t3510-cherry-pick-sequence.sh

diff --git a/builtin/revert.c b/builtin/revert.c
index 9c29852..b04cf39 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -13,6 +13,7 @@
 #include "rerere.h"
 #include "merge-recursive.h"
 #include "refs.h"
+#include "dir.h"
 
 /*
  * This implements the builtins revert and cherry-pick.
@@ -60,6 +61,10 @@ struct replay_opts {
 
 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
 
+#define SEQ_DIR         "sequencer"
+#define SEQ_HEAD_FILE   "sequencer/head"
+#define SEQ_TODO_FILE   "sequencer/todo"
+
 static const char *action_name(const struct replay_opts *opts)
 {
 	return opts->action == REVERT ? "revert" : "cherry-pick";
@@ -587,10 +592,116 @@ static void read_and_refresh_cache(struct replay_opts *opts)
 	rollback_lock_file(&index_lock);
 }
 
-static int pick_commits(struct replay_opts *opts)
+/*
+ * Append a commit to the end of the commit_list.
+ *
+ * next starts by pointing to the variable that holds the head of an
+ * empty commit_list, and is updated to point to the "next" field of
+ * the last item on the list as new commits are appended.
+ *
+ * Usage example:
+ *
+ *     struct commit_list *list;
+ *     struct commit_list **next = &list;
+ *
+ *     next = commit_list_append(c1, next);
+ *     next = commit_list_append(c2, next);
+ *     assert(commit_list_count(list) == 2);
+ *     return list;
+ */
+struct commit_list **commit_list_append(struct commit *commit,
+					struct commit_list **next)
+{
+	struct commit_list *new = xmalloc(sizeof(struct commit_list));
+	new->item = commit;
+	*next = new;
+	new->next = NULL;
+	return &new->next;
+}
+
+static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
+		struct replay_opts *opts)
+{
+	struct commit_list *cur = NULL;
+	struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
+	const char *sha1_abbrev = NULL;
+	const char *action_str = opts->action == REVERT ? "revert" : "pick";
+
+	for (cur = todo_list; cur; cur = cur->next) {
+		sha1_abbrev = find_unique_abbrev(cur->item->object.sha1, DEFAULT_ABBREV);
+		if (get_message(cur->item, &msg))
+			return error(_("Cannot get commit message for %s"), sha1_abbrev);
+		strbuf_addf(buf, "%s %s %s\n", action_str, sha1_abbrev, msg.subject);
+	}
+	return 0;
+}
+
+static void walk_revs_populate_todo(struct commit_list **todo_list,
+				struct replay_opts *opts)
 {
 	struct rev_info revs;
 	struct commit *commit;
+	struct commit_list **next;
+
+	prepare_revs(&revs, opts);
+
+	next = todo_list;
+	while ((commit = get_revision(&revs)))
+		next = commit_list_append(commit, next);
+}
+
+static void create_seq_dir(void)
+{
+	const char *seq_dir = git_path(SEQ_DIR);
+
+	if (!(file_exists(seq_dir) && is_directory(seq_dir))
+		&& mkdir(seq_dir, 0777) < 0)
+		die_errno(_("Could not create sequencer directory '%s'."), seq_dir);
+}
+
+static void save_head(const char *head)
+{
+	const char *head_file = git_path(SEQ_HEAD_FILE);
+	static struct lock_file head_lock;
+	struct strbuf buf = STRBUF_INIT;
+	int fd;
+
+	fd = hold_lock_file_for_update(&head_lock, head_file, LOCK_DIE_ON_ERROR);
+	strbuf_addf(&buf, "%s\n", head);
+	if (write_in_full(fd, buf.buf, buf.len) < 0)
+		die_errno(_("Could not write to %s."), head_file);
+	if (commit_lock_file(&head_lock) < 0)
+		die(_("Error wrapping up %s."), head_file);
+}
+
+static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
+{
+	const char *todo_file = git_path(SEQ_TODO_FILE);
+	static struct lock_file todo_lock;
+	struct strbuf buf = STRBUF_INIT;
+	int fd;
+
+	fd = hold_lock_file_for_update(&todo_lock, todo_file, LOCK_DIE_ON_ERROR);
+	if (format_todo(&buf, todo_list, opts) < 0)
+		die(_("Could not format %s."), todo_file);
+	if (write_in_full(fd, buf.buf, buf.len) < 0) {
+		strbuf_release(&buf);
+		die_errno(_("Could not write to %s."), todo_file);
+	}
+	if (commit_lock_file(&todo_lock) < 0) {
+		strbuf_release(&buf);
+		die(_("Error wrapping up %s."), todo_file);
+	}
+	strbuf_release(&buf);
+}
+
+static int pick_commits(struct replay_opts *opts)
+{
+	struct commit_list *todo_list = NULL;
+	struct strbuf buf = STRBUF_INIT;
+	unsigned char sha1[20];
+	struct commit_list *cur;
+	int res;
 
 	setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
 	if (opts->allow_ff)
@@ -598,14 +709,29 @@ static int pick_commits(struct replay_opts *opts)
 				opts->record_origin || opts->edit));
 	read_and_refresh_cache(opts);
 
-	prepare_revs(&revs, opts);
+	walk_revs_populate_todo(&todo_list, opts);
+	create_seq_dir();
+	if (get_sha1("HEAD", sha1)) {
+		if (opts->action == REVERT)
+			die(_("Can't revert as initial commit"));
+		die(_("Can't cherry-pick into empty head"));
+	}
+	save_head(sha1_to_hex(sha1));
 
-	while ((commit = get_revision(&revs))) {
-		int res = do_pick_commit(commit, opts);
+	for (cur = todo_list; cur; cur = cur->next) {
+		save_todo(cur, opts);
+		res = do_pick_commit(cur->item, opts);
 		if (res)
 			return res;
 	}
 
+	/*
+	 * Sequence of picks finished successfully; cleanup by
+	 * removing the .git/sequencer directory
+	 */
+	strbuf_reset(&buf);
+	strbuf_addf(&buf, "%s", git_path(SEQ_DIR));
+	remove_dir_recursively(&buf, 0);
 	return 0;
 }
 
diff --git a/t/t3510-cherry-pick-sequence.sh b/t/t3510-cherry-pick-sequence.sh
new file mode 100755
index 0000000..890e59c
--- /dev/null
+++ b/t/t3510-cherry-pick-sequence.sh
@@ -0,0 +1,48 @@
+#!/bin/sh
+
+test_description='Test cherry-pick continuation features
+
+  + anotherpick: rewrites foo to d
+  + picked: rewrites foo to c
+  + unrelatedpick: rewrites unrelated to reallyunrelated
+  + base: rewrites foo to b
+  + initial: writes foo as a, unrelated as unrelated
+
+'
+
+. ./test-lib.sh
+
+pristine_detach () {
+	git checkout -f "$1^0" &&
+	git read-tree -u --reset HEAD &&
+	git clean -d -f -f -q -x
+}
+
+test_expect_success setup '
+	echo unrelated >unrelated &&
+	git add unrelated &&
+	test_commit initial foo a &&
+	test_commit base foo b &&
+	test_commit unrelatedpick unrelated reallyunrelated &&
+	test_commit picked foo c &&
+	test_commit anotherpick foo d &&
+	git config advice.detachedhead false
+
+'
+
+test_expect_success 'cherry-pick persists data on failure' '
+	pristine_detach initial &&
+	test_must_fail git cherry-pick base..anotherpick &&
+	test_path_is_dir .git/sequencer &&
+	test_path_is_file .git/sequencer/head &&
+	test_path_is_file .git/sequencer/todo
+'
+
+test_expect_success 'cherry-pick cleans up sequencer state upon success' '
+	rm -rf .git/sequencer &&
+	pristine_detach initial &&
+	git cherry-pick initial..picked &&
+	test_path_is_missing .git/sequencer
+'
+
+test_done
-- 
1.7.4.rc1.7.g2cf08.dirty

Re: [PATCH 10/18] revert: Save data for continuing after conflict resolution

[Jonathan Nieder]

Ramkumar Ramachandra wrote:

> That these two files alone are not enough to implement a "--continue"
> that remembers the command-line options specified; later patches in
> the series save them too.

Micronit: I think this sentence has an extra "That".

[...]
> +	if (!(file_exists(seq_dir) && is_directory(seq_dir))
> +		&& mkdir(seq_dir, 0777) < 0)
> +		die_errno(_("Could not create sequencer directory '%s'."), seq_dir);

Nice, thanks.

[...]
> +pristine_detach () {
> +	git checkout -f "$1^0" &&
> +	git read-tree -u --reset HEAD &&
> +	git clean -d -f -f -q -x
> +}

Nit: probably best to include the "rm -rf .git/sequencer" in this
function.  But I don't think that should hold up the patch.

Aside from typos in commit messages as mentioned before, the patches up
to here look ready.

Re: [PATCH 10/18] revert: Save data for continuing after conflict resolution

[Ramkumar Ramachandra]

Hi again,

Jonathan Nieder writes:
> Ramkumar Ramachandra wrote:
>> That these two files alone are not enough to implement a "--continue"
>> that remembers the command-line options specified; later patches in
>> the series save them too.
>
> Micronit: I think this sentence has an extra "That".

Ugh.  Fixed.

>> +pristine_detach () {
>> +     git checkout -f "$1^0" &&
>> +     git read-tree -u --reset HEAD &&
>> +     git clean -d -f -f -q -x
>> +}
>
> Nit: probably best to include the "rm -rf .git/sequencer" in this
> function.  But I don't think that should hold up the patch.

Ah, good idea.  Fixed.

Thanks.

-- Ram

[PATCH 11/18] revert: Save command-line options for continuing operation

[Ramkumar Ramachandra]

In the same spirit as ".git/sequencer/head" and ".git/sequencer/todo",
introduce ".git/sequencer/opts" to persist the replay_opts structure
for continuing after a conflict resolution.  Use the gitconfig format
for this file so that it looks like:

  [options]
	  signoff = true
	  record-origin = true
	  mainline = 1
	  strategy = recursive
	  strategy-option = patience
	  strategy-option = ours

Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/revert.c                |   35 +++++++++++++++++++++++++++++++++++
 t/t3510-cherry-pick-sequence.sh |   30 ++++++++++++++++++++++++++++--
 2 files changed, 63 insertions(+), 2 deletions(-)

diff --git a/builtin/revert.c b/builtin/revert.c
index b04cf39..f561f33 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -64,6 +64,7 @@ struct replay_opts {
 #define SEQ_DIR         "sequencer"
 #define SEQ_HEAD_FILE   "sequencer/head"
 #define SEQ_TODO_FILE   "sequencer/todo"
+#define SEQ_OPTS_FILE   "sequencer/opts"
 
 static const char *action_name(const struct replay_opts *opts)
 {
@@ -695,6 +696,39 @@ static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
 	strbuf_release(&buf);
 }
 
+static void save_opts(struct replay_opts *opts)
+{
+	const char *opts_file = git_path(SEQ_OPTS_FILE);
+	struct strbuf buf = STRBUF_INIT;
+	int i;
+
+	if (opts->no_commit)
+		git_config_set_in_file(opts_file, "options.no-commit", "true");
+	if (opts->edit)
+		git_config_set_in_file(opts_file, "options.edit", "true");
+	if (opts->signoff)
+		git_config_set_in_file(opts_file, "options.signoff", "true");
+	if (opts->record_origin)
+		git_config_set_in_file(opts_file, "options.record-origin", "true");
+	if (opts->allow_ff)
+		git_config_set_in_file(opts_file, "options.allow-ff", "true");
+	if (opts->mainline) {
+		strbuf_reset(&buf);
+		strbuf_addf(&buf, "%d", opts->mainline);
+		git_config_set_in_file(opts_file, "options.mainline", buf.buf);
+	}
+	if (opts->strategy)
+		git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
+	if (opts->xopts) {
+		for (i = 0; i < opts->xopts_nr; i++)
+			git_config_set_multivar_in_file(opts_file,
+							"options.strategy-option",
+							opts->xopts[i], "^$", 0);
+	}
+
+	strbuf_release(&buf);
+}
+
 static int pick_commits(struct replay_opts *opts)
 {
 	struct commit_list *todo_list = NULL;
@@ -717,6 +751,7 @@ static int pick_commits(struct replay_opts *opts)
 		die(_("Can't cherry-pick into empty head"));
 	}
 	save_head(sha1_to_hex(sha1));
+	save_opts(opts);
 
 	for (cur = todo_list; cur; cur = cur->next) {
 		save_todo(cur, opts);
diff --git a/t/t3510-cherry-pick-sequence.sh b/t/t3510-cherry-pick-sequence.sh
index 890e59c..f3fab7d 100755
--- a/t/t3510-cherry-pick-sequence.sh
+++ b/t/t3510-cherry-pick-sequence.sh
@@ -32,10 +32,36 @@ test_expect_success setup '
 
 test_expect_success 'cherry-pick persists data on failure' '
 	pristine_detach initial &&
-	test_must_fail git cherry-pick base..anotherpick &&
+	test_must_fail git cherry-pick -s base..anotherpick &&
 	test_path_is_dir .git/sequencer &&
 	test_path_is_file .git/sequencer/head &&
-	test_path_is_file .git/sequencer/todo
+	test_path_is_file .git/sequencer/todo &&
+	test_path_is_file .git/sequencer/opts
+'
+
+test_expect_success 'cherry-pick persists opts correctly' '
+	rm -rf .git/sequencer &&
+	pristine_detach initial &&
+	test_must_fail git cherry-pick -s -m 1 --strategy=recursive -X patience -X ours base..anotherpick &&
+	test_path_is_dir .git/sequencer &&
+	test_path_is_file .git/sequencer/head &&
+	test_path_is_file .git/sequencer/todo &&
+	test_path_is_file .git/sequencer/opts &&
+	echo "true" >expect
+	git config --file=.git/sequencer/opts --get-all options.signoff >actual &&
+	test_cmp expect actual &&
+	echo "1" >expect
+	git config --file=.git/sequencer/opts --get-all options.mainline >actual &&
+	test_cmp expect actual &&
+	echo "recursive" >expect
+	git config --file=.git/sequencer/opts --get-all options.strategy >actual &&
+	test_cmp expect actual &&
+	cat >expect <<-\EOF
+	patience
+	ours
+	EOF
+	git config --file=.git/sequencer/opts --get-all options.strategy-option >actual &&
+	test_cmp expect actual
 '
 
 test_expect_success 'cherry-pick cleans up sequencer state upon success' '
-- 
1.7.4.rc1.7.g2cf08.dirty

Re: [PATCH 11/18] revert: Save command-line options for continuing operation

[Christian Couder]

On Thursday 28 July 2011 18:52:24 Ramkumar Ramachandra wrote:
>
> +static void save_opts(struct replay_opts *opts)
> +{
> +	const char *opts_file = git_path(SEQ_OPTS_FILE);
> +	struct strbuf buf = STRBUF_INIT;
> +	int i;
> +
> +	if (opts->no_commit)
> +		git_config_set_in_file(opts_file, "options.no-commit", "true");
> +	if (opts->edit)
> +		git_config_set_in_file(opts_file, "options.edit", "true");
> +	if (opts->signoff)
> +		git_config_set_in_file(opts_file, "options.signoff", "true");
> +	if (opts->record_origin)
> +		git_config_set_in_file(opts_file, "options.record-origin", "true");
> +	if (opts->allow_ff)
> +		git_config_set_in_file(opts_file, "options.allow-ff", "true");
> +	if (opts->mainline) {
> +		strbuf_reset(&buf);

It is not necessary to reset &buf here.

> +		strbuf_addf(&buf, "%d", opts->mainline);
> +		git_config_set_in_file(opts_file, "options.mainline", buf.buf);
> +	}

And perhaps it would be clearer if it was:

+       if (opts->mainline) {
+               struct strbuf buf = STRBUF_INIT;
+               strbuf_addf(&buf, "%d", opts->mainline);
+               git_config_set_in_file(opts_file, "options.mainline", buf.buf);
+               strbuf_release(&buf);
+       }

> +	if (opts->strategy)
> +		git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
> +	if (opts->xopts) {

Other nit: maybe you could put "int i" here, instead of at the beginning of 
the function.

> +		for (i = 0; i < opts->xopts_nr; i++)
> +			git_config_set_multivar_in_file(opts_file,
> +							"options.strategy-option",
> +							opts->xopts[i], "^$", 0);
> +	}
> +
> +	strbuf_release(&buf);
> +}

Thanks,
Christian.

Re: [PATCH 11/18] revert: Save command-line options for continuing operation

[Ramkumar Ramachandra]

Hi,

Christian Couder writes:
> On Thursday 28 July 2011 18:52:24 Ramkumar Ramachandra wrote:
>> +     if (opts->mainline) {
>> +             strbuf_reset(&buf);
>
> It is not necessary to reset &buf here.
>
>> +             strbuf_addf(&buf, "%d", opts->mainline);
>> +             git_config_set_in_file(opts_file, "options.mainline", buf.buf);
>> +     }
>
> And perhaps it would be clearer if it was:
>
> +       if (opts->mainline) {
> +               struct strbuf buf = STRBUF_INIT;
> +               strbuf_addf(&buf, "%d", opts->mainline);
> +               git_config_set_in_file(opts_file, "options.mainline", buf.buf);
> +               strbuf_release(&buf);
> +       }

Much clearer.  Fixed.

>> +     if (opts->strategy)
>> +             git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
>> +     if (opts->xopts) {
>
> Other nit: maybe you could put "int i" here, instead of at the beginning of
> the function.

Fixed.  Thanks.

-- Ram

[PATCH 12/18] revert: Make pick_commits functionally act on a commit list

[Ramkumar Ramachandra]

Apart from its central objective of calling into the picking
mechanism, pick_commits creates a sequencer directory, prepares a todo
list, and even acts upon the "--reset" subcommand.  This makes for a
bad API since the central worry of callers is to figure out whether or
not any conflicts were encountered during the cherry picking.  The
current API is like:

  if (pick_commits(opts) < 0)
     print "Something failed, we're not sure what"

So, change pick_commits so that it's only responsible for picking
commits in a loop and reporting any errors, leaving the rest to a new
function called pick_revisions.  Consequently, the API of pick_commits
becomes much clearer:

  act_on_subcommand(opts->subcommand);
  todo_list = prepare_todo_list();
  if (pick_commits(todo_list, opts) < 0)
     print "Error encountered while picking commits"

Now, callers can easily call-in to the cherry-picking machinery by
constructing an arbitrary todo list along with some options.

Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/revert.c |   45 ++++++++++++++++++++++++++++++---------------
 1 files changed, 30 insertions(+), 15 deletions(-)

diff --git a/builtin/revert.c b/builtin/revert.c
index f561f33..14259db 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -729,11 +729,9 @@ static void save_opts(struct replay_opts *opts)
 	strbuf_release(&buf);
 }
 
-static int pick_commits(struct replay_opts *opts)
+static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
 {
-	struct commit_list *todo_list = NULL;
 	struct strbuf buf = STRBUF_INIT;
-	unsigned char sha1[20];
 	struct commit_list *cur;
 	int res;
 
@@ -743,16 +741,6 @@ static int pick_commits(struct replay_opts *opts)
 				opts->record_origin || opts->edit));
 	read_and_refresh_cache(opts);
 
-	walk_revs_populate_todo(&todo_list, opts);
-	create_seq_dir();
-	if (get_sha1("HEAD", sha1)) {
-		if (opts->action == REVERT)
-			die(_("Can't revert as initial commit"));
-		die(_("Can't cherry-pick into empty head"));
-	}
-	save_head(sha1_to_hex(sha1));
-	save_opts(opts);
-
 	for (cur = todo_list; cur; cur = cur->next) {
 		save_todo(cur, opts);
 		res = do_pick_commit(cur->item, opts);
@@ -770,6 +758,27 @@ static int pick_commits(struct replay_opts *opts)
 	return 0;
 }
 
+static int pick_revisions(struct replay_opts *opts)
+{
+	struct commit_list *todo_list = NULL;
+	unsigned char sha1[20];
+
+	read_and_refresh_cache(opts);
+
+	walk_revs_populate_todo(&todo_list, opts);
+	create_seq_dir();
+	if (get_sha1("HEAD", sha1)) {
+		if (opts->action == REVERT)
+			die(_("Can't revert as initial commit"));
+		die(_("Can't cherry-pick into empty head"));
+	} else
+		save_head(sha1_to_hex(sha1));
+	save_opts(opts);
+	save_todo(todo_list, opts);
+
+	return pick_commits(todo_list, opts);
+}
+
 int cmd_revert(int argc, const char **argv, const char *prefix)
 {
 	struct replay_opts opts;
@@ -780,7 +789,13 @@ int cmd_revert(int argc, const char **argv, const char *prefix)
 	opts.action = REVERT;
 	git_config(git_default_config, NULL);
 	parse_args(argc, argv, &opts);
-	return pick_commits(&opts);
+
+	/*
+	 * Decide what to do depending on the arguments; a fresh
+	 * cherry-pick should be handled differently from an existing
+	 * one that is being continued
+	 */
+	return pick_revisions(&opts);
 }
 
 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
@@ -791,5 +806,5 @@ int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 	opts.action = CHERRY_PICK;
 	git_config(git_default_config, NULL);
 	parse_args(argc, argv, &opts);
-	return pick_commits(&opts);
+	return pick_revisions(&opts);
 }
-- 
1.7.4.rc1.7.g2cf08.dirty

Re: [PATCH 12/18] revert: Make pick_commits functionally act on a commit list

[Christian Couder]

On Thursday 28 July 2011 18:52:25 Ramkumar Ramachandra wrote:
>
> @@ -780,7 +789,13 @@ int cmd_revert(int argc, const char **argv, const char
> *prefix) opts.action = REVERT;
>  	git_config(git_default_config, NULL);
>  	parse_args(argc, argv, &opts);
> -	return pick_commits(&opts);
> +
> +	/*
> +	 * Decide what to do depending on the arguments; a fresh
> +	 * cherry-pick should be handled differently from an existing
> +	 * one that is being continued
> +	 */

It is strange to me that you add this comment only here and not below in 
cmd_cherry_pick(). So I'd suggest to put it before the definition of 
pick_revisions() instead.

> +	return pick_revisions(&opts);
>  }
> 
>  int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
> @@ -791,5 +806,5 @@ int cmd_cherry_pick(int argc, const char **argv, const
> char *prefix) opts.action = CHERRY_PICK;
>  	git_config(git_default_config, NULL);
>  	parse_args(argc, argv, &opts);
> -	return pick_commits(&opts);
> +	return pick_revisions(&opts);
>  }

Thanks,
Christian.

Re: [PATCH 12/18] revert: Make pick_commits functionally act on a commit list

[Christian Couder]

On Thursday 28 July 2011 18:52:25 Ramkumar Ramachandra wrote:
> @@ -743,16 +741,6 @@ static int pick_commits(struct replay_opts *opts)
>  				opts->record_origin || opts->edit));
>  	read_and_refresh_cache(opts);
> 
> -	walk_revs_populate_todo(&todo_list, opts);
> -	create_seq_dir();
> -	if (get_sha1("HEAD", sha1)) {
> -		if (opts->action == REVERT)
> -			die(_("Can't revert as initial commit"));
> -		die(_("Can't cherry-pick into empty head"));
> -	}
> -	save_head(sha1_to_hex(sha1));
> -	save_opts(opts);
> -
>  	for (cur = todo_list; cur; cur = cur->next) {
>  		save_todo(cur, opts);
>  		res = do_pick_commit(cur->item, opts);
> @@ -770,6 +758,27 @@ static int pick_commits(struct replay_opts *opts)
>  	return 0;
>  }
> 
> +static int pick_revisions(struct replay_opts *opts)
> +{
> +	struct commit_list *todo_list = NULL;
> +	unsigned char sha1[20];
> +
> +	read_and_refresh_cache(opts);
> +
> +	walk_revs_populate_todo(&todo_list, opts);
> +	create_seq_dir();
> +	if (get_sha1("HEAD", sha1)) {
> +		if (opts->action == REVERT)
> +			die(_("Can't revert as initial commit"));
> +		die(_("Can't cherry-pick into empty head"));
> +	} else

This "else" could be removed.

> +		save_head(sha1_to_hex(sha1));
> +	save_opts(opts);
> +	save_todo(todo_list, opts);

This save_todo() could be removed too as pick_commits() already does it.

> +	return pick_commits(todo_list, opts);
> +}

Thanks,
Christian.

Re: [PATCH 12/18] revert: Make pick_commits functionally act on a commit list

[Ramkumar Ramachandra]

Hi Christian,

Christian Couder writes:
> On Thursday 28 July 2011 18:52:25 Ramkumar Ramachandra wrote:
>> +     /*
>> +      * Decide what to do depending on the arguments; a fresh
>> +      * cherry-pick should be handled differently from an existing
>> +      * one that is being continued
>> +      */
>
> It is strange to me that you add this comment only here and not below in
> cmd_cherry_pick(). So I'd suggest to put it before the definition of
> pick_revisions() instead.

Fixed.

>> +     if (get_sha1("HEAD", sha1)) {
>> +             if (opts->action == REVERT)
>> +                     die(_("Can't revert as initial commit"));
>> +             die(_("Can't cherry-pick into empty head"));
>> +     } else
>
> This "else" could be removed.

Fixed.

>> +             save_head(sha1_to_hex(sha1));
>> +     save_opts(opts);
>> +     save_todo(todo_list, opts);
>
> This save_todo() could be removed too as pick_commits() already does it.

Consider what effect this will have: pick_commits() may die before it
calls the save_todo() in a couple of ways:
1. The opts->allow_ff assertion block fails.  Although this can't
happen now (due to parse_args already catching it), it might happen
sometime in the future when we have a public API.  The question we
should be asking is: Is it alright to persist the todo in this case?
I'd say no -- the caller needs to be fixed, and persisting the todo
really isn't something I'd expect as an end user at this point.
2. read_and_refresh_cache fails.  Same question: Is it alright to
persist the todo in this case?  Failing to read or refresh the index
is quite a serious error, and persisting a todo is the last thing a
user would expect at this point anyway.  So, no again.

Result: Fixed.

Thanks.

-- Ram

[PATCH 13/18] revert: Introduce --reset to remove sequencer state

[Ramkumar Ramachandra]

To explicitly remove the sequencer state for a fresh cherry-pick or
revert invocation, introduce a new subcommand called "--reset" to
remove the sequencer state.

Take the opportunity to publicly expose the sequencer paths, and a
generic function called "remove_sequencer_state" that various git
programs can use to remove the sequencer state in a uniform manner;
"git reset" uses it later in this series.  Introducing this public API
is also in line with our long-term goal of eventually factoring out
functions from revert.c into a generic commit sequencer.

Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 Documentation/git-cherry-pick.txt |    5 +++
 Documentation/git-revert.txt      |    5 +++
 Documentation/sequencer.txt       |    4 ++
 Makefile                          |    2 +
 builtin/revert.c                  |   63 +++++++++++++++++++++++++------------
 sequencer.c                       |   19 +++++++++++
 sequencer.h                       |   20 ++++++++++++
 t/t3510-cherry-pick-sequence.sh   |   18 +++++++++-
 8 files changed, 114 insertions(+), 22 deletions(-)
 create mode 100644 Documentation/sequencer.txt
 create mode 100644 sequencer.c
 create mode 100644 sequencer.h

diff --git a/Documentation/git-cherry-pick.txt b/Documentation/git-cherry-pick.txt
index 6c9c2cb..12a85ba 100644
--- a/Documentation/git-cherry-pick.txt
+++ b/Documentation/git-cherry-pick.txt
@@ -9,6 +9,7 @@ SYNOPSIS
 --------
 [verse]
 'git cherry-pick' [--edit] [-n] [-m parent-number] [-s] [-x] [--ff] <commit>...
+'git cherry-pick' --reset
 
 DESCRIPTION
 -----------
@@ -110,6 +111,10 @@ effect to your index in a row.
 	Pass the merge strategy-specific option through to the
 	merge strategy.  See linkgit:git-merge[1] for details.
 
+SEQUENCER SUBCOMMANDS
+---------------------
+include::sequencer.txt[]
+
 EXAMPLES
 --------
 git cherry-pick master::
diff --git a/Documentation/git-revert.txt b/Documentation/git-revert.txt
index 3d0a7d1..31c85b4 100644
--- a/Documentation/git-revert.txt
+++ b/Documentation/git-revert.txt
@@ -9,6 +9,7 @@ SYNOPSIS
 --------
 [verse]
 'git revert' [--edit | --no-edit] [-n] [-m parent-number] [-s] <commit>...
+'git revert' --reset
 
 DESCRIPTION
 -----------
@@ -91,6 +92,10 @@ effect to your index in a row.
 	Pass the merge strategy-specific option through to the
 	merge strategy.  See linkgit:git-merge[1] for details.
 
+SEQUENCER SUBCOMMANDS
+---------------------
+include::sequencer.txt[]
+
 EXAMPLES
 --------
 git revert HEAD~3::
diff --git a/Documentation/sequencer.txt b/Documentation/sequencer.txt
new file mode 100644
index 0000000..16ce88c
--- /dev/null
+++ b/Documentation/sequencer.txt
@@ -0,0 +1,4 @@
+--reset::
+	Forget about the current operation in progress.  Can be used
+	to clear the sequencer state after a failed cherry-pick or
+	revert.
diff --git a/Makefile b/Makefile
index 4ed7996..afd7673 100644
--- a/Makefile
+++ b/Makefile
@@ -554,6 +554,7 @@ LIB_H += rerere.h
 LIB_H += resolve-undo.h
 LIB_H += revision.h
 LIB_H += run-command.h
+LIB_H += sequencer.h
 LIB_H += sha1-array.h
 LIB_H += sha1-lookup.h
 LIB_H += sideband.h
@@ -658,6 +659,7 @@ LIB_OBJS += revision.o
 LIB_OBJS += run-command.o
 LIB_OBJS += server-info.o
 LIB_OBJS += setup.o
+LIB_OBJS += sequencer.o
 LIB_OBJS += sha1-array.o
 LIB_OBJS += sha1-lookup.o
 LIB_OBJS += sha1_file.o
diff --git a/builtin/revert.c b/builtin/revert.c
index 14259db..70b9f65 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -14,6 +14,7 @@
 #include "merge-recursive.h"
 #include "refs.h"
 #include "dir.h"
+#include "sequencer.h"
 
 /*
  * This implements the builtins revert and cherry-pick.
@@ -28,18 +29,22 @@
 
 static const char * const revert_usage[] = {
 	"git revert [options] <commit-ish>",
+	"git revert <subcommand>",
 	NULL
 };
 
 static const char * const cherry_pick_usage[] = {
 	"git cherry-pick [options] <commit-ish>",
+	"git cherry-pick <subcommand>",
 	NULL
 };
 
 enum replay_action { REVERT, CHERRY_PICK };
+enum replay_subcommand { REPLAY_NONE, REPLAY_RESET };
 
 struct replay_opts {
 	enum replay_action action;
+	enum replay_subcommand subcommand;
 
 	/* Boolean options */
 	int edit;
@@ -61,11 +66,6 @@ struct replay_opts {
 
 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
 
-#define SEQ_DIR         "sequencer"
-#define SEQ_HEAD_FILE   "sequencer/head"
-#define SEQ_TODO_FILE   "sequencer/todo"
-#define SEQ_OPTS_FILE   "sequencer/opts"
-
 static const char *action_name(const struct replay_opts *opts)
 {
 	return opts->action == REVERT ? "revert" : "cherry-pick";
@@ -113,7 +113,9 @@ static void parse_args(int argc, const char **argv, struct replay_opts *opts)
 	const char * const * usage_str = revert_or_cherry_pick_usage(opts);
 	const char *me = action_name(opts);
 	int noop;
+	int reset = 0;
 	struct option options[] = {
+		OPT_BOOLEAN(0, "reset", &reset, "forget the current operation"),
 		OPT_BOOLEAN('n', "no-commit", &opts->no_commit, "don't automatically commit"),
 		OPT_BOOLEAN('e', "edit", &opts->edit, "edit the commit message"),
 		{ OPTION_BOOLEAN, 'r', NULL, &noop, NULL, "no-op (backward compatibility)",
@@ -142,7 +144,27 @@ static void parse_args(int argc, const char **argv, struct replay_opts *opts)
 	opts->commit_argc = parse_options(argc, argv, NULL, options, usage_str,
 					PARSE_OPT_KEEP_ARGV0 |
 					PARSE_OPT_KEEP_UNKNOWN);
-	if (opts->commit_argc < 2)
+
+	/* Set the subcommand */
+	if (reset)
+		opts->subcommand = REPLAY_RESET;
+	else
+		opts->subcommand = REPLAY_NONE;
+
+	/* Check for incompatible command line arguments */
+	if (opts->subcommand == REPLAY_RESET) {
+		verify_opt_compatible(me, "--reset",
+				"--no-commit", opts->no_commit,
+				"--signoff", opts->signoff,
+				"--mainline", opts->mainline,
+				"--strategy", opts->strategy ? 1 : 0,
+				"--strategy-option", opts->xopts ? 1 : 0,
+				"-x", opts->record_origin,
+				"--ff", opts->allow_ff,
+				NULL);
+	}
+
+	else if (opts->commit_argc < 2)
 		usage_with_options(usage_str, options);
 
 	if (opts->allow_ff)
@@ -731,7 +753,6 @@ static void save_opts(struct replay_opts *opts)
 
 static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
 {
-	struct strbuf buf = STRBUF_INIT;
 	struct commit_list *cur;
 	int res;
 
@@ -752,9 +773,7 @@ static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
 	 * Sequence of picks finished successfully; cleanup by
 	 * removing the .git/sequencer directory
 	 */
-	strbuf_reset(&buf);
-	strbuf_addf(&buf, "%s", git_path(SEQ_DIR));
-	remove_dir_recursively(&buf, 0);
+	remove_sequencer_state(1);
 	return 0;
 }
 
@@ -765,17 +784,21 @@ static int pick_revisions(struct replay_opts *opts)
 
 	read_and_refresh_cache(opts);
 
-	walk_revs_populate_todo(&todo_list, opts);
-	create_seq_dir();
-	if (get_sha1("HEAD", sha1)) {
-		if (opts->action == REVERT)
-			die(_("Can't revert as initial commit"));
-		die(_("Can't cherry-pick into empty head"));
-	} else
+	if (opts->subcommand == REPLAY_RESET) {
+		remove_sequencer_state(1);
+		return 0;
+	} else {
+		/* Start a new cherry-pick/ revert sequence */
+		walk_revs_populate_todo(&todo_list, opts);
+		create_seq_dir();
+		if (get_sha1("HEAD", sha1)) {
+			if (opts->action == REVERT)
+				die(_("Can't revert as initial commit"));
+			die(_("Can't cherry-pick into empty head"));
+		}
 		save_head(sha1_to_hex(sha1));
-	save_opts(opts);
-	save_todo(todo_list, opts);
-
+		save_opts(opts);
+	}
 	return pick_commits(todo_list, opts);
 }
 
diff --git a/sequencer.c b/sequencer.c
new file mode 100644
index 0000000..bc2c046
--- /dev/null
+++ b/sequencer.c
@@ -0,0 +1,19 @@
+#include "cache.h"
+#include "sequencer.h"
+#include "strbuf.h"
+#include "dir.h"
+
+void remove_sequencer_state(int aggressive)
+{
+	struct strbuf seq_dir = STRBUF_INIT;
+	struct strbuf seq_old_dir = STRBUF_INIT;
+
+	strbuf_addf(&seq_dir, "%s", git_path(SEQ_DIR));
+	strbuf_addf(&seq_old_dir, "%s", git_path(SEQ_OLD_DIR));
+	remove_dir_recursively(&seq_old_dir, 0);
+	rename(git_path(SEQ_DIR), git_path(SEQ_OLD_DIR));
+	if (aggressive)
+		remove_dir_recursively(&seq_old_dir, 0);
+	strbuf_release(&seq_dir);
+	strbuf_release(&seq_old_dir);
+}
diff --git a/sequencer.h b/sequencer.h
new file mode 100644
index 0000000..905d295
--- /dev/null
+++ b/sequencer.h
@@ -0,0 +1,20 @@
+#ifndef SEQUENCER_H
+#define SEQUENCER_H
+
+#define SEQ_DIR		"sequencer"
+#define SEQ_OLD_DIR	"sequencer-old"
+#define SEQ_HEAD_FILE	"sequencer/head"
+#define SEQ_TODO_FILE	"sequencer/todo"
+#define SEQ_OPTS_FILE	"sequencer/opts"
+
+/*
+ * Removes SEQ_OLD_DIR and renames SEQ_DIR to SEQ_OLD_DIR, ignoring
+ * any errors.  Intended to be used by 'git reset'.
+ *
+ * With the aggressive flag, it additionally removes SEQ_OLD_DIR,
+ * ignoring any errors.  Inteded to be used by the sequencer's
+ * '--reset' subcommand.
+ */
+void remove_sequencer_state(int aggressive);
+
+#endif
diff --git a/t/t3510-cherry-pick-sequence.sh b/t/t3510-cherry-pick-sequence.sh
index f3fab7d..49df209 100755
--- a/t/t3510-cherry-pick-sequence.sh
+++ b/t/t3510-cherry-pick-sequence.sh
@@ -40,7 +40,7 @@ test_expect_success 'cherry-pick persists data on failure' '
 '
 
 test_expect_success 'cherry-pick persists opts correctly' '
-	rm -rf .git/sequencer &&
+	git cherry-pick --reset &&
 	pristine_detach initial &&
 	test_must_fail git cherry-pick -s -m 1 --strategy=recursive -X patience -X ours base..anotherpick &&
 	test_path_is_dir .git/sequencer &&
@@ -65,10 +65,24 @@ test_expect_success 'cherry-pick persists opts correctly' '
 '
 
 test_expect_success 'cherry-pick cleans up sequencer state upon success' '
-	rm -rf .git/sequencer &&
+	git cherry-pick --reset &&
 	pristine_detach initial &&
 	git cherry-pick initial..picked &&
 	test_path_is_missing .git/sequencer
 '
 
+test_expect_success '--reset does not complain when no cherry-pick is in progress' '
+	git cherry-pick --reset &&
+	pristine_detach initial &&
+	git cherry-pick --reset
+'
+
+test_expect_success '--reset cleans up sequencer state' '
+	git cherry-pick --reset &&
+	pristine_detach initial &&
+	test_must_fail git cherry-pick base..picked &&
+	git cherry-pick --reset &&
+	test_path_is_missing .git/sequencer
+'
+
 test_done
-- 
1.7.4.rc1.7.g2cf08.dirty

Re: [PATCH 13/18] revert: Introduce --reset to remove sequencer state

[Christian Couder]

On Thursday 28 July 2011 18:52:26 Ramkumar Ramachandra wrote:
>
> @@ -765,17 +784,21 @@ static int pick_revisions(struct replay_opts *opts)
> 
>  	read_and_refresh_cache(opts);
> 
> -	walk_revs_populate_todo(&todo_list, opts);
> -	create_seq_dir();
> -	if (get_sha1("HEAD", sha1)) {
> -		if (opts->action == REVERT)
> -			die(_("Can't revert as initial commit"));
> -		die(_("Can't cherry-pick into empty head"));
> -	} else
> +	if (opts->subcommand == REPLAY_RESET) {
> +		remove_sequencer_state(1);
> +		return 0;
> +	} else {

Maybe you could remove this "else" so that the indentation level is reduced. 

> +		/* Start a new cherry-pick/ revert sequence */
> +		walk_revs_populate_todo(&todo_list, opts);
> +		create_seq_dir();
> +		if (get_sha1("HEAD", sha1)) {
> +			if (opts->action == REVERT)
> +				die(_("Can't revert as initial commit"));
> +			die(_("Can't cherry-pick into empty head"));
> +		}
>  		save_head(sha1_to_hex(sha1));
> -	save_opts(opts);
> -	save_todo(todo_list, opts);

It looks like this save_todo() was not necessary in the first place because 
pick_commits() does a save_todo() before processing each commit.

> -
> +		save_opts(opts);
> +	}
>  	return pick_commits(todo_list, opts);
>  }

Re: [PATCH 13/18] revert: Introduce --reset to remove sequencer state

[Ramkumar Ramachandra]

Hi Christian,

Christian Couder writes:
> On Thursday 28 July 2011 18:52:26 Ramkumar Ramachandra wrote:
>> @@ -765,17 +784,21 @@ static int pick_revisions(struct replay_opts *opts)
>>
>>       read_and_refresh_cache(opts);
>>
>> -     walk_revs_populate_todo(&todo_list, opts);
>> -     create_seq_dir();
>> -     if (get_sha1("HEAD", sha1)) {
>> -             if (opts->action == REVERT)
>> -                     die(_("Can't revert as initial commit"));
>> -             die(_("Can't cherry-pick into empty head"));
>> -     } else
>> +     if (opts->subcommand == REPLAY_RESET) {
>> +             remove_sequencer_state(1);
>> +             return 0;
>> +     } else {
>
> Maybe you could remove this "else" so that the indentation level is reduced.

This was intentional, mainly for stylistic reasons.  See [1].

>> +             /* Start a new cherry-pick/ revert sequence */
>> +             walk_revs_populate_todo(&todo_list, opts);
>> +             create_seq_dir();
>> +             if (get_sha1("HEAD", sha1)) {
>> +                     if (opts->action == REVERT)
>> +                             die(_("Can't revert as initial commit"));
>> +                     die(_("Can't cherry-pick into empty head"));
>> +             }
>>               save_head(sha1_to_hex(sha1));
>> -     save_opts(opts);
>> -     save_todo(todo_list, opts);
>
> It looks like this save_todo() was not necessary in the first place because
> pick_commits() does a save_todo() before processing each commit.

Fixed in the earlier patch.  Thanks!

[1]: http://thread.gmane.org/gmane.comp.version-control.git/177960

Thanks.

-- Ram

[PATCH 14/18] reset: Make reset remove the sequencer state

[Ramkumar Ramachandra]

Years of muscle memory have trained users to use "git reset --hard" to
remove the branch state after any sort operation.  Make it also remove
the sequencer state to facilitate this established workflow:

  $ git cherry-pick foo..bar
  ... conflict encountered ...
  $ git reset --hard # Oops, I didn't mean that
  $ git cherry-pick quux..bar
  ... cherry-pick succeeded ...

Guard against accidental removal of the sequencer state by providing
one level of "undo".  In the first "reset" invocation,
".git/sequencer" is moved to ".git/sequencer-old"; it is completely
removed only in the second invocation.

Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 branch.c                 |    2 ++
 t/7106-reset-sequence.sh |   43 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+), 0 deletions(-)
 create mode 100755 t/7106-reset-sequence.sh

diff --git a/branch.c b/branch.c
index c0c865a..d06aec4 100644
--- a/branch.c
+++ b/branch.c
@@ -3,6 +3,7 @@
 #include "refs.h"
 #include "remote.h"
 #include "commit.h"
+#include "sequencer.h"
 
 struct tracking {
 	struct refspec spec;
@@ -228,4 +229,5 @@ void remove_branch_state(void)
 	unlink(git_path("MERGE_MSG"));
 	unlink(git_path("MERGE_MODE"));
 	unlink(git_path("SQUASH_MSG"));
+	remove_sequencer_state(0);
 }
diff --git a/t/7106-reset-sequence.sh b/t/7106-reset-sequence.sh
new file mode 100755
index 0000000..c61c62d
--- /dev/null
+++ b/t/7106-reset-sequence.sh
@@ -0,0 +1,43 @@
+#!/bin/sh
+
+test_description='Test interaction of reset --hard with sequencer
+
+  + anotherpick: rewrites foo to d
+  + picked: rewrites foo to c
+  + unrelatedpick: rewrites unrelated to reallyunrelated
+  + base: rewrites foo to b
+  + initial: writes foo as a, unrelated as unrelated
+'
+
+. ./test-lib.sh
+
+pristine_detach () {
+	git checkout -f "$1^0" &&
+	git read-tree -u --reset HEAD &&
+	git clean -d -f -f -q -x
+}
+
+test_expect_success setup '
+	echo unrelated >unrelated &&
+	git add unrelated &&
+	test_commit initial foo a &&
+	test_commit base foo b &&
+	test_commit unrelatedpick unrelated reallyunrelated &&
+	test_commit picked foo c &&
+	test_commit anotherpick foo d &&
+	git config advice.detachedhead false
+
+'
+
+test_expect_success 'reset --hard cleans up sequencer state, providing one-level undo' '
+	pristine_detach initial &&
+	test_must_fail git cherry-pick base..anotherpick &&
+	test_path_is_dir .git/sequencer &&
+	git reset --hard &&
+	test_path_is_missing .git/sequencer &&
+	test_path_is_dir .git/sequencer-old &&
+	git reset --hard &&
+	test_path_is_missing .git/sequencer-old
+'
+
+test_done
-- 
1.7.4.rc1.7.g2cf08.dirty

[PATCH 15/18] revert: Remove sequencer state when no commits are pending

[Ramkumar Ramachandra]

When cherry-pick or revert is called on a list of commits, and a
conflict encountered somewhere in the middle, the data in
".git/sequencer" is required to continue the operation.  However, when
a conflict is encountered in the very last commit, the user will have
to "continue" after resolving the conflict and committing just so that
the sequencer state is removed.  This is how the current "rebase -i"
script works as well.

  $ git cherry-pick foo..bar
  ... conflict encountered while picking "bar" ...
  $ echo "resolved" >problematicfile
  $ git add problematicfile
  $ git commit
  $ git cherry-pick --continue # This would be a noop

Change this so that the sequencer state is cleared when a conflict is
encountered in the last commit.  Incidentally, this patch makes sure
that some existing tests don't break when features like "--reset" and
"--continue" are implemented later in the series.

Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/revert.c                |   12 +++++++++++-
 t/t3510-cherry-pick-sequence.sh |   25 +++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 1 deletions(-)

diff --git a/builtin/revert.c b/builtin/revert.c
index 70b9f65..80a2ef7 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -765,8 +765,18 @@ static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
 	for (cur = todo_list; cur; cur = cur->next) {
 		save_todo(cur, opts);
 		res = do_pick_commit(cur->item, opts);
-		if (res)
+		if (res) {
+			if (!cur->next)
+				/*
+				 * An error was encountered while
+				 * picking the last commit; the
+				 * sequencer state is useless now --
+				 * the user simply needs to resolve
+				 * the conflict and commit
+				 */
+				remove_sequencer_state(0);
 			return res;
+		}
 	}
 
 	/*
diff --git a/t/t3510-cherry-pick-sequence.sh b/t/t3510-cherry-pick-sequence.sh
index 49df209..528f270 100755
--- a/t/t3510-cherry-pick-sequence.sh
+++ b/t/t3510-cherry-pick-sequence.sh
@@ -85,4 +85,29 @@ test_expect_success '--reset cleans up sequencer state' '
 	test_path_is_missing .git/sequencer
 '
 
+test_expect_success 'cherry-pick cleans up sequencer state when one commit is left' '
+	git cherry-pick --reset &&
+	pristine_detach initial &&
+	test_must_fail git cherry-pick base..picked &&
+	test_path_is_missing .git/sequencer &&
+	echo "resolved" >foo &&
+	git add foo &&
+	git commit &&
+	{
+		git rev-list HEAD |
+		git diff-tree --root --stdin |
+		sed "s/$_x40/OBJID/g"
+	} >actual &&
+	cat >expect <<-\EOF &&
+	OBJID
+	:100644 100644 OBJID OBJID M	foo
+	OBJID
+	:100644 100644 OBJID OBJID M	unrelated
+	OBJID
+	:000000 100644 OBJID OBJID A	foo
+	:000000 100644 OBJID OBJID A	unrelated
+	EOF
+	test_cmp expect actual
+'
+
 test_done
-- 
1.7.4.rc1.7.g2cf08.dirty

[PATCH 16/18] revert: Don't implictly stomp pending sequencer operation

[Ramkumar Ramachandra]

Protect the user from forgetting about a pending sequencer operation
by immediately erroring out when an existing cherry-pick or revert
operation is in progress like:

  $ git cherry-pick foo
  ... conflict ...
  $ git cherry-pick moo
  error: .git/sequencer already exists
  hint: A cherry-pick or revert is in progress
  hint: Use --reset to forget about it
  fatal: cherry-pick failed

A naive version of this would break the following established ways of
working:

  $ git cherry-pick foo
  ... conflict ...
  $ git reset --hard  # I actually meant "moo" when I said "foo"
  $ git cherry-pick moo

  $ git cherry-pick foo
  ... conflict ...
  $ git commit # commit the resolution
  $ git cherry-pick moo # New operation

However, the previous patches "reset: Make reset remove the sequencer
state" and "revert: Remove sequencer state when no commits are
pending" make sure that this does not happen.

Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/revert.c                |   30 +++++++++++++++++++++++++-----
 t/t3510-cherry-pick-sequence.sh |   10 ++++++++++
 2 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/builtin/revert.c b/builtin/revert.c
index 80a2ef7..e173c71 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -66,6 +66,15 @@ struct replay_opts {
 
 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
 
+static void fatal(const char *advice, ...)
+{
+	va_list params;
+
+	va_start(params, advice);
+	vreportf("fatal: ", advice, params);
+	va_end(params);
+}
+
 static const char *action_name(const struct replay_opts *opts)
 {
 	return opts->action == REVERT ? "revert" : "cherry-pick";
@@ -673,13 +682,15 @@ static void walk_revs_populate_todo(struct commit_list **todo_list,
 		next = commit_list_append(commit, next);
 }
 
-static void create_seq_dir(void)
+static int create_seq_dir(void)
 {
 	const char *seq_dir = git_path(SEQ_DIR);
 
-	if (!(file_exists(seq_dir) && is_directory(seq_dir))
-		&& mkdir(seq_dir, 0777) < 0)
+	if (file_exists(seq_dir))
+		return error(_("%s already exists."), seq_dir);
+	else if (mkdir(seq_dir, 0777) < 0)
 		die_errno(_("Could not create sequencer directory '%s'."), seq_dir);
+	return 0;
 }
 
 static void save_head(const char *head)
@@ -798,9 +809,18 @@ static int pick_revisions(struct replay_opts *opts)
 		remove_sequencer_state(1);
 		return 0;
 	} else {
-		/* Start a new cherry-pick/ revert sequence */
+		/*
+		 * Start a new cherry-pick/ revert sequence; but
+		 * first, make sure that an existing one isn't in
+		 * progress
+		 */
+
 		walk_revs_populate_todo(&todo_list, opts);
-		create_seq_dir();
+		if (create_seq_dir() < 0) {
+			fatal(_("A cherry-pick or revert is in progress."));
+			advise(_("Use --reset to forget about it"));
+			exit(128);
+		}
 		if (get_sha1("HEAD", sha1)) {
 			if (opts->action == REVERT)
 				die(_("Can't revert as initial commit"));
diff --git a/t/t3510-cherry-pick-sequence.sh b/t/t3510-cherry-pick-sequence.sh
index 528f270..342cab3 100755
--- a/t/t3510-cherry-pick-sequence.sh
+++ b/t/t3510-cherry-pick-sequence.sh
@@ -110,4 +110,14 @@ test_expect_success 'cherry-pick cleans up sequencer state when one commit is le
 	test_cmp expect actual
 '
 
+test_expect_success 'cherry-pick does not implicitly stomp an existing operation' '
+	git cherry-pick --reset &&
+	pristine_detach initial &&
+	test_must_fail git cherry-pick base..anotherpick &&
+	test-chmtime -v +0 .git/sequencer >expect &&
+	test_must_fail git cherry-pick unrelatedpick &&
+	test-chmtime -v +0 .git/sequencer >actual &&
+	test_cmp expect actual
+'
+
 test_done
-- 
1.7.4.rc1.7.g2cf08.dirty

[PATCH 17/18] revert: Introduce --continue to continue the operation

[Ramkumar Ramachandra]

Introduce a new "git cherry-pick --continue" command which uses the
information in ".git/sequencer" to continue a cherry-pick that stopped
because of a conflict or other error.  It works by dropping the first
instruction from .git/sequencer/todo and performing the remaining
cherry-picks listed there, with options (think "-s" and "-X") from the
initial command listed in ".git/sequencer/opts".

So now you can do:

  $ git cherry-pick -Xpatience foo..bar
  ... description conflict in commit moo ...
  $ git cherry-pick --continue
  error: 'cherry-pick' is not possible because you have unmerged files.
  fatal: failed to resume cherry-pick
  $ echo resolved >conflictingfile
  $ git add conflictingfile && git commit
  $ git cherry-pick --continue; # resumes with the commit after "moo"

During the "git commit" stage, CHERRY_PICK_HEAD will aid by providing
the commit message from the conflicting "moo" commit.  Note that the
cherry-pick mechanism has no control at this stage, so the user is
free to violate anything that was specified during the first
cherry-pick invocation.  For example, if "-x" was specified during the
first cherry-pick invocation, the user is free to edit out the message
during commit time.  Note that the "--signoff" option specified at
cherry-pick invocation time is not reflected in the commit message
provided by CHERRY_PICK_HEAD; the user must take care to add
"--signoff" during the "git commit" invocation.

Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 Documentation/git-cherry-pick.txt |    1 +
 Documentation/git-revert.txt      |    1 +
 Documentation/sequencer.txt       |    5 +
 builtin/revert.c                  |  184 ++++++++++++++++++++++++++++++++++++-
 t/t3510-cherry-pick-sequence.sh   |  102 ++++++++++++++++++++
 5 files changed, 289 insertions(+), 4 deletions(-)

diff --git a/Documentation/git-cherry-pick.txt b/Documentation/git-cherry-pick.txt
index 12a85ba..b4a2d74 100644
--- a/Documentation/git-cherry-pick.txt
+++ b/Documentation/git-cherry-pick.txt
@@ -10,6 +10,7 @@ SYNOPSIS
 [verse]
 'git cherry-pick' [--edit] [-n] [-m parent-number] [-s] [-x] [--ff] <commit>...
 'git cherry-pick' --reset
+'git cherry-pick' --continue
 
 DESCRIPTION
 -----------
diff --git a/Documentation/git-revert.txt b/Documentation/git-revert.txt
index 31c85b4..68f8e68 100644
--- a/Documentation/git-revert.txt
+++ b/Documentation/git-revert.txt
@@ -10,6 +10,7 @@ SYNOPSIS
 [verse]
 'git revert' [--edit | --no-edit] [-n] [-m parent-number] [-s] <commit>...
 'git revert' --reset
+'git revert' --continue
 
 DESCRIPTION
 -----------
diff --git a/Documentation/sequencer.txt b/Documentation/sequencer.txt
index 16ce88c..3e6df33 100644
--- a/Documentation/sequencer.txt
+++ b/Documentation/sequencer.txt
@@ -2,3 +2,8 @@
 	Forget about the current operation in progress.  Can be used
 	to clear the sequencer state after a failed cherry-pick or
 	revert.
+
+--continue::
+	Continue the operation in progress using the information in
+	'.git/sequencer'.  Can be used to continue after resolving
+	conflicts in a failed cherry-pick or revert.
diff --git a/builtin/revert.c b/builtin/revert.c
index e173c71..985f49f 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -40,7 +40,7 @@ static const char * const cherry_pick_usage[] = {
 };
 
 enum replay_action { REVERT, CHERRY_PICK };
-enum replay_subcommand { REPLAY_NONE, REPLAY_RESET };
+enum replay_subcommand { REPLAY_NONE, REPLAY_RESET, REPLAY_CONTINUE };
 
 struct replay_opts {
 	enum replay_action action;
@@ -117,14 +117,40 @@ static void verify_opt_compatible(const char *me, const char *base_opt, ...)
 	va_end(ap);
 }
 
+static void verify_opt_mutually_compatible(const char *me, ...)
+{
+	const char *opt1, *opt2;
+	va_list ap;
+	int set;
+
+	va_start(ap, me);
+	while ((opt1 = va_arg(ap, const char *))) {
+		set = va_arg(ap, int);
+		if (set)
+			break;
+	}
+	if (!opt1)
+		goto ok;
+	while ((opt2 = va_arg(ap, const char *))) {
+		set = va_arg(ap, int);
+		if (set)
+			die(_("%s: %s cannot be used with %s"),
+				me, opt1, opt2);
+	}
+ok:
+	va_end(ap);
+}
+
 static void parse_args(int argc, const char **argv, struct replay_opts *opts)
 {
 	const char * const * usage_str = revert_or_cherry_pick_usage(opts);
 	const char *me = action_name(opts);
 	int noop;
 	int reset = 0;
+	int contin = 0;
 	struct option options[] = {
 		OPT_BOOLEAN(0, "reset", &reset, "forget the current operation"),
+		OPT_BOOLEAN(0, "continue", &contin, "continue the current operation"),
 		OPT_BOOLEAN('n', "no-commit", &opts->no_commit, "don't automatically commit"),
 		OPT_BOOLEAN('e', "edit", &opts->edit, "edit the commit message"),
 		{ OPTION_BOOLEAN, 'r', NULL, &noop, NULL, "no-op (backward compatibility)",
@@ -154,15 +180,29 @@ static void parse_args(int argc, const char **argv, struct replay_opts *opts)
 					PARSE_OPT_KEEP_ARGV0 |
 					PARSE_OPT_KEEP_UNKNOWN);
 
+	/* Check for incompatible subcommands */
+	verify_opt_mutually_compatible(me,
+				"--reset", reset,
+				"--continue", contin,
+				NULL);
+
 	/* Set the subcommand */
 	if (reset)
 		opts->subcommand = REPLAY_RESET;
+	else if (contin)
+		opts->subcommand = REPLAY_CONTINUE;
 	else
 		opts->subcommand = REPLAY_NONE;
 
 	/* Check for incompatible command line arguments */
-	if (opts->subcommand == REPLAY_RESET) {
-		verify_opt_compatible(me, "--reset",
+	if (opts->subcommand != REPLAY_NONE) {
+		char *this_operation;
+		if (opts->subcommand == REPLAY_RESET)
+			this_operation = "--reset";
+		else
+			this_operation = "--continue";
+
+		verify_opt_compatible(me, this_operation,
 				"--no-commit", opts->no_commit,
 				"--signoff", opts->signoff,
 				"--mainline", opts->mainline,
@@ -668,6 +708,130 @@ static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
 	return 0;
 }
 
+static struct commit *parse_insn_line(char *start, struct replay_opts *opts)
+{
+	unsigned char commit_sha1[20];
+	char sha1_abbrev[40];
+	enum replay_action action;
+	int insn_len = 0;
+	char *p, *q;
+
+	if (!prefixcmp(start, "pick ")) {
+		action = CHERRY_PICK;
+		insn_len = strlen("pick");
+		p = start + insn_len + 1;
+	} else if (!prefixcmp(start, "revert ")) {
+		action = REVERT;
+		insn_len = strlen("revert");
+		p = start + insn_len + 1;
+	} else
+		return NULL;
+
+	q = strchr(p, ' ');
+	if (!q)
+		return NULL;
+	q++;
+
+	strlcpy(sha1_abbrev, p, q - p);
+
+	/*
+	 * Verify that the action matches up with the one in
+	 * opts; we don't support arbitrary instructions
+	 */
+	if (action != opts->action) {
+		const char *action_str;
+		action_str = action == REVERT ? "revert" : "cherry-pick";
+		error(_("Cannot %s during a %s"), action_str, action_name(opts));
+		return NULL;
+	}
+
+	if (get_sha1(sha1_abbrev, commit_sha1) < 0)
+		return NULL;
+
+	return lookup_commit_reference(commit_sha1);
+}
+
+static void read_populate_todo(struct commit_list **todo_list,
+			struct replay_opts *opts)
+{
+	const char *todo_file = git_path(SEQ_TODO_FILE);
+	struct strbuf buf = STRBUF_INIT;
+	struct commit_list **next;
+	struct commit *commit;
+	char *p;
+	int fd;
+
+	fd = open(todo_file, O_RDONLY);
+	if (fd < 0) {
+		strbuf_release(&buf);
+		die_errno(_("Could not open %s."), todo_file);
+	}
+	if (strbuf_read(&buf, fd, 0) < buf.len) {
+		close(fd);
+		strbuf_release(&buf);
+		die(_("Could not read %s."), todo_file);
+	}
+	close(fd);
+
+	next = todo_list;
+	for (p = buf.buf; *p; p = strchr(p, '\n') + 1) {
+		commit = parse_insn_line(p, opts);
+		if (!commit)
+			goto error;
+		next = commit_list_append(commit, next);
+	}
+	if (!*todo_list)
+		goto error;
+	strbuf_release(&buf);
+	return;
+error:
+	strbuf_release(&buf);
+	die(_("Unusable instruction sheet: %s"), todo_file);
+}
+
+static int populate_opts_cb(const char *key, const char *value, void *data)
+{
+	struct replay_opts *opts = data;
+	int error_flag = 1;
+
+	if (!value)
+		error_flag = 0;
+	else if (!strcmp(key, "options.no-commit"))
+		opts->no_commit = git_config_bool_or_int(key, value, &error_flag);
+	else if (!strcmp(key, "options.edit"))
+		opts->edit = git_config_bool_or_int(key, value, &error_flag);
+	else if (!strcmp(key, "options.signoff"))
+		opts->signoff = git_config_bool_or_int(key, value, &error_flag);
+	else if (!strcmp(key, "options.record-origin"))
+		opts->record_origin = git_config_bool_or_int(key, value, &error_flag);
+	else if (!strcmp(key, "options.allow-ff"))
+		opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
+	else if (!strcmp(key, "options.mainline"))
+		opts->mainline = git_config_int(key, value);
+	else if (!strcmp(key, "options.strategy"))
+		git_config_string(&opts->strategy, key, value);
+	else if (!strcmp(key, "options.strategy-option")) {
+		ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
+		opts->xopts[opts->xopts_nr++] = xstrdup(value);
+	} else
+		return error(_("Invalid key: %s"), key);
+
+	if (!error_flag)
+		return error(_("Invalid value for %s: %s"), key, value);
+
+	return 0;
+}
+
+static void read_populate_opts(struct replay_opts **opts_ptr)
+{
+	const char *opts_file = git_path(SEQ_OPTS_FILE);
+
+	if (!file_exists(opts_file))
+		return;
+	if (git_config_from_file(populate_opts_cb, opts_file, *opts_ptr) < 0)
+		die(_("Malformed options sheet: %s"), opts_file);
+}
+
 static void walk_revs_populate_todo(struct commit_list **todo_list,
 				struct replay_opts *opts)
 {
@@ -808,6 +972,15 @@ static int pick_revisions(struct replay_opts *opts)
 	if (opts->subcommand == REPLAY_RESET) {
 		remove_sequencer_state(1);
 		return 0;
+	} else if (opts->subcommand == REPLAY_CONTINUE) {
+		if (!file_exists(git_path(SEQ_TODO_FILE)))
+			goto error;
+		read_populate_opts(&opts);
+		read_populate_todo(&todo_list, opts);
+
+		/* Verify that the conflict has been resolved */
+		if (!index_differs_from("HEAD", 0))
+			todo_list = todo_list->next;
 	} else {
 		/*
 		 * Start a new cherry-pick/ revert sequence; but
@@ -818,7 +991,8 @@ static int pick_revisions(struct replay_opts *opts)
 		walk_revs_populate_todo(&todo_list, opts);
 		if (create_seq_dir() < 0) {
 			fatal(_("A cherry-pick or revert is in progress."));
-			advise(_("Use --reset to forget about it"));
+			advise(_("Use --continue to continue the operation"));
+			advise(_("or --reset to forget about it"));
 			exit(128);
 		}
 		if (get_sha1("HEAD", sha1)) {
@@ -830,6 +1004,8 @@ static int pick_revisions(struct replay_opts *opts)
 		save_opts(opts);
 	}
 	return pick_commits(todo_list, opts);
+error:
+	die(_("No %s in progress"), action_name(opts));
 }
 
 int cmd_revert(int argc, const char **argv, const char *prefix)
diff --git a/t/t3510-cherry-pick-sequence.sh b/t/t3510-cherry-pick-sequence.sh
index 342cab3..88ea6a4 100755
--- a/t/t3510-cherry-pick-sequence.sh
+++ b/t/t3510-cherry-pick-sequence.sh
@@ -120,4 +120,106 @@ test_expect_success 'cherry-pick does not implicitly stomp an existing operation
 	test_cmp expect actual
 '
 
+test_expect_success '--continue complains when no cherry-pick is in progress' '
+	git cherry-pick --reset &&
+	pristine_detach initial &&
+	test_must_fail git cherry-pick --continue
+'
+
+test_expect_success '--continue complains when there are unresolved conflicts' '
+	git cherry-pick --reset &&
+	pristine_detach initial &&
+	test_must_fail git cherry-pick base..picked &&
+	test_must_fail git cherry-pick --continue
+'
+
+test_expect_success '--continue continues after conflicts are resolved' '
+	git cherry-pick --reset &&
+	pristine_detach initial &&
+	test_must_fail git cherry-pick base..anotherpick &&
+	echo "c" >foo &&
+	git add foo &&
+	git commit &&
+	git cherry-pick --continue &&
+	test_path_is_missing .git/sequencer &&
+	{
+		git rev-list HEAD |
+		git diff-tree --root --stdin |
+		sed "s/$_x40/OBJID/g"
+	} >actual &&
+	cat >expect <<-\EOF &&
+	OBJID
+	:100644 100644 OBJID OBJID M	foo
+	OBJID
+	:100644 100644 OBJID OBJID M	foo
+	OBJID
+	:100644 100644 OBJID OBJID M	unrelated
+	OBJID
+	:000000 100644 OBJID OBJID A	foo
+	:000000 100644 OBJID OBJID A	unrelated
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success '--continue respects opts' '
+	git cherry-pick --reset &&
+	pristine_detach initial &&
+	test_must_fail git cherry-pick -x base..anotherpick &&
+	echo "c" >foo &&
+	git add foo &&
+	git commit &&
+	git cherry-pick --continue &&
+	test_path_is_missing .git/sequencer &&
+	git cat-file commit HEAD >anotherpick_msg &&
+	git cat-file commit HEAD~1 >picked_msg &&
+	git cat-file commit HEAD~2 >unrelatedpick_msg &&
+	git cat-file commit HEAD~3 >initial_msg &&
+	test_must_fail grep "cherry picked from" initial_msg &&
+	grep "cherry picked from" unrelatedpick_msg &&
+	grep "cherry picked from" picked_msg &&
+	grep "cherry picked from" anotherpick_msg
+'
+
+test_expect_success '--signoff is not automatically propogated to resolved conflict' '
+	pristine_detach initial &&
+	test_must_fail git cherry-pick --signoff base..anotherpick &&
+	echo "c" >foo &&
+	git add foo &&
+	git commit &&
+	git cherry-pick --continue &&
+	test_path_is_missing .git/sequencer &&
+	git cat-file commit HEAD >anotherpick_msg &&
+	git cat-file commit HEAD~1 >picked_msg &&
+	git cat-file commit HEAD~2 >unrelatedpick_msg &&
+	git cat-file commit HEAD~3 >initial_msg &&
+	test_must_fail grep "Signed-off-by:" initial_msg &&
+	grep "Signed-off-by:" unrelatedpick_msg &&
+	test_must_fail grep "Signed-off-by:" picked_msg &&
+	grep "Signed-off-by:" anotherpick_msg
+'
+
+test_expect_success 'malformed instruction sheet 1' '
+	git cherry-pick --reset &&
+	pristine_detach initial &&
+	test_must_fail git cherry-pick base..picked &&
+	echo "resolved" >foo &&
+	git add foo &&
+	git commit &&
+	sed "s/pick /pick/" .git/sequencer/todo >new_sheet
+	cp new_sheet .git/sequencer/todo
+	test_must_fail git cherry-pick --continue
+'
+
+test_expect_success 'malformed instruction sheet 2' '
+	git cherry-pick --reset &&
+	pristine_detach initial &&
+	test_must_fail git cherry-pick base..picked &&
+	echo "resolved" >foo &&
+	git add foo &&
+	git commit &&
+	sed "s/pick/revert/" .git/sequencer/todo >new_sheet
+	cp new_sheet .git/sequencer/todo
+	test_must_fail git cherry-pick --continue
+'
+
 test_done
-- 
1.7.4.rc1.7.g2cf08.dirty

Re: [PATCH 17/18] revert: Introduce --continue to continue the operation

[Christian Couder]

On Thursday 28 July 2011 18:52:30 Ramkumar Ramachandra wrote:
> +static void read_populate_todo(struct commit_list **todo_list,
> +			struct replay_opts *opts)
> +{
> +	const char *todo_file = git_path(SEQ_TODO_FILE);
> +	struct strbuf buf = STRBUF_INIT;
> +	struct commit_list **next;
> +	struct commit *commit;
> +	char *p;
> +	int fd;
> +
> +	fd = open(todo_file, O_RDONLY);
> +	if (fd < 0) {
> +		strbuf_release(&buf);

We don't need to release buf here.

> +		die_errno(_("Could not open %s."), todo_file);
> +	}
> +	if (strbuf_read(&buf, fd, 0) < buf.len) {

The other places in the code are using "strbuf_read(...) < 0" to detect an 
error.

> +		close(fd);
> +		strbuf_release(&buf);
> +		die(_("Could not read %s."), todo_file);
> +	}
> +	close(fd);
> +
> +	next = todo_list;
> +	for (p = buf.buf; *p; p = strchr(p, '\n') + 1) {

This relies on a "\n" at the end of the last line...

> +		commit = parse_insn_line(p, opts);
> +		if (!commit)
> +			goto error;
> +		next = commit_list_append(commit, next);
> +	}
> +	if (!*todo_list)
> +		goto error;
> +	strbuf_release(&buf);
> +	return;
> +error:
> +	strbuf_release(&buf);
> +	die(_("Unusable instruction sheet: %s"), todo_file);
> +}

Thanks,
Christian.

Re: [PATCH 17/18] revert: Introduce --continue to continue the operation

[Ramkumar Ramachandra]

Hi again,

Christian Couder writes:
> On Thursday 28 July 2011 18:52:30 Ramkumar Ramachandra wrote:
>> +static void read_populate_todo(struct commit_list **todo_list,
>> +                     struct replay_opts *opts)
>> +{
>> +     const char *todo_file = git_path(SEQ_TODO_FILE);
>> +     struct strbuf buf = STRBUF_INIT;
>> +     struct commit_list **next;
>> +     struct commit *commit;
>> +     char *p;
>> +     int fd;
>> +
>> +     fd = open(todo_file, O_RDONLY);
>> +     if (fd < 0) {
>> +             strbuf_release(&buf);
>
> We don't need to release buf here.

Good catch!  Fixed.

>> +             die_errno(_("Could not open %s."), todo_file);
>> +     }
>> +     if (strbuf_read(&buf, fd, 0) < buf.len) {
>
> The other places in the code are using "strbuf_read(...) < 0" to detect an
> error.

Ah, I hadn't noticed.  See, strbuf_reset can return in two ways:
1. strbuf.c:313 reads "return -1", and this is clearly an error.
2. strbuf.c:322 reads "return sb->len - oldlen", and I thought I
should catch short reads using this.  Then again, malformed
instruction sheets are reported anyway during the parse anyway.

Fixed for consistency with other code.

>> +             close(fd);
>> +             strbuf_release(&buf);
>> +             die(_("Could not read %s."), todo_file);
>> +     }
>> +     close(fd);
>> +
>> +     next = todo_list;
>> +     for (p = buf.buf; *p; p = strchr(p, '\n') + 1) {
>
> This relies on a "\n" at the end of the last line...

Yes, that was intentional.  Every editor I know of inserts a '\n' at
the end of the last line, and I've seen some applications warn/ break
when the last line is not terminated with '\n'.  I suppose another
reason to not change this is consistency -- we don't have to handle
the last line using a special case.  So, I personally don't like it,
but I'll add a special case if you insist.

Thanks.

-- Ram

Re: [PATCH 17/18] revert: Introduce --continue to continue the operation

[Jonathan Nieder]

Ramkumar Ramachandra wrote:
>> On Thursday 28 July 2011 18:52:30 Ramkumar Ramachandra wrote:

>>> +     for (p = buf.buf; *p; p = strchr(p, '\n') + 1) {
[...]
> Yes, that was intentional.  Every editor I know of inserts a '\n' at
> the end of the last line, and I've seen some applications warn/ break
> when the last line is not terminated with '\n'.  I suppose another
> reason to not change this is consistency -- we don't have to handle
> the last line using a special case.  So, I personally don't like it,
> but I'll add a special case if you insist.

What is the failure mode?  If it is a baffling segfault, then I
insist.

Re: [PATCH 17/18] revert: Introduce --continue to continue the operation

[Junio C Hamano]

Ramkumar Ramachandra <artagnon@gmail.com> writes:

>>> +     for (p = buf.buf; *p; p = strchr(p, '\n') + 1) {
>>
>> This relies on a "\n" at the end of the last line...
>
> Yes, that was intentional.  Every editor I know of inserts a '\n' at
> the end of the last line,...

Why do you think "diff" has a special codepath to report "No newline at
end of file"? Because some editors do leave an incomplete line incomplete.

When working on a "buf" with an incomplete line at the end, the last round
of the loop will assign "(char *) 1" to "p", try to see "*p" is NUL and
segfault, no?

Re: [PATCH 17/18] revert: Introduce --continue to continue the operation

[Ramkumar Ramachandra]

Hi Junio,

Junio C Hamano writes:
> Ramkumar Ramachandra <artagnon@gmail.com> writes:
>>>> +     for (p = buf.buf; *p; p = strchr(p, '\n') + 1) {
>>>
>>> This relies on a "\n" at the end of the last line...
>>
>> Yes, that was intentional.  Every editor I know of inserts a '\n' at
>> the end of the last line,...
>
> Why do you think "diff" has a special codepath to report "No newline at
> end of file"? Because some editors do leave an incomplete line incomplete.
>
> When working on a "buf" with an incomplete line at the end, the last round
> of the loop will assign "(char *) 1" to "p", try to see "*p" is NUL and
> segfault, no?

Thanks for the excellent explanation! :)
I'll fix this and re-roll asap: I'll take the opportunity to include
the other changes that Christian suggested.

-- Ram

[PATCH 18/18] revert: Propogate errors upwards from do_pick_commit

[Ramkumar Ramachandra]

Currently, revert_or_cherry_pick can fail in two ways.  If it
encounters a conflict, it returns a positive number indicating the
intended exit status for the git wrapper to pass on; for all other
errors, it calls die().  The latter behavior is inconsiderate towards
callers, as it denies them the opportunity to recover from errors and
do other things.

After this patch, revert_or_cherry_pick will still return a positive
return value to indicate an exit status for conflicts as before, while
for some other errors, it will print an error message and return -1
instead of die()-ing.  The cmd_revert and cmd_cherry_pick are adjusted
to handle the fatal errors by die()-ing themselves.

While the full benefits of this patch will only be seen once all the
"die" calls are replaced with calls to "error", its immediate impact
is to change some "fatal:" messages to say "error:" and to add a new
"fatal: cherry-pick failed" message at the end when the operation
fails.

Inspired-by: Christian Couder <chriscool@tuxfamily.org>
Mentored-by: Jonathan Nieder <jrnieder@gmail.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/revert.c |   86 +++++++++++++++++++++++++-----------------------------
 1 files changed, 40 insertions(+), 46 deletions(-)

diff --git a/builtin/revert.c b/builtin/revert.c
index 985f49f..f30dbd4 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -66,15 +66,6 @@ struct replay_opts {
 
 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
 
-static void fatal(const char *advice, ...)
-{
-	va_list params;
-
-	va_start(params, advice);
-	vreportf("fatal: ", advice, params);
-	va_end(params);
-}
-
 static const char *action_name(const struct replay_opts *opts)
 {
 	return opts->action == REVERT ? "revert" : "cherry-pick";
@@ -359,25 +350,20 @@ static struct tree *empty_tree(void)
 	return tree;
 }
 
-static NORETURN void die_dirty_index(struct replay_opts *opts)
+static int error_dirty_index(struct replay_opts *opts)
 {
-	if (read_cache_unmerged()) {
-		die_resolve_conflict(action_name(opts));
-	} else {
-		if (advice_commit_before_merge) {
-			if (opts->action == REVERT)
-				die(_("Your local changes would be overwritten by revert.\n"
-					  "Please, commit your changes or stash them to proceed."));
-			else
-				die(_("Your local changes would be overwritten by cherry-pick.\n"
-					  "Please, commit your changes or stash them to proceed."));
-		} else {
-			if (opts->action == REVERT)
-				die(_("Your local changes would be overwritten by revert.\n"));
-			else
-				die(_("Your local changes would be overwritten by cherry-pick.\n"));
-		}
-	}
+	if (read_cache_unmerged())
+		return error_resolve_conflict(action_name(opts));
+
+	/* Different translation strings for cherry-pick and revert */
+	if (opts->action == CHERRY_PICK)
+		error(_("Your local changes would be overwritten by cherry-pick."));
+	else
+		error(_("Your local changes would be overwritten by revert."));
+
+	if (advice_commit_before_merge)
+		advise(_("Commit your changes or stash them to proceed."));
+	return -1;
 }
 
 static int fast_forward_to(const unsigned char *to, const unsigned char *from)
@@ -495,9 +481,9 @@ static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 			die (_("Your index file is unmerged."));
 	} else {
 		if (get_sha1("HEAD", head))
-			die (_("You do not have a valid HEAD"));
+			return error(_("You do not have a valid HEAD"));
 		if (index_differs_from("HEAD", 0))
-			die_dirty_index(opts);
+			return error_dirty_index(opts);
 	}
 	discard_cache();
 
@@ -510,20 +496,20 @@ static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 		struct commit_list *p;
 
 		if (!opts->mainline)
-			die(_("Commit %s is a merge but no -m option was given."),
-			    sha1_to_hex(commit->object.sha1));
+			return error(_("Commit %s is a merge but no -m option was given."),
+				sha1_to_hex(commit->object.sha1));
 
 		for (cnt = 1, p = commit->parents;
 		     cnt != opts->mainline && p;
 		     cnt++)
 			p = p->next;
 		if (cnt != opts->mainline || !p)
-			die(_("Commit %s does not have parent %d"),
-			    sha1_to_hex(commit->object.sha1), opts->mainline);
+			return error(_("Commit %s does not have parent %d"),
+				sha1_to_hex(commit->object.sha1), opts->mainline);
 		parent = p->item;
 	} else if (0 < opts->mainline)
-		die(_("Mainline was specified but commit %s is not a merge."),
-		    sha1_to_hex(commit->object.sha1));
+		return error(_("Mainline was specified but commit %s is not a merge."),
+			sha1_to_hex(commit->object.sha1));
 	else
 		parent = commit->parents->item;
 
@@ -533,12 +519,12 @@ static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 	if (parent && parse_commit(parent) < 0)
 		/* TRANSLATORS: The first %s will be "revert" or
 		   "cherry-pick", the second %s a SHA1 */
-		die(_("%s: cannot parse parent commit %s"),
-		    action_name(opts), sha1_to_hex(parent->object.sha1));
+		return error(_("%s: cannot parse parent commit %s"),
+			action_name(opts), sha1_to_hex(parent->object.sha1));
 
 	if (get_message(commit, &msg) != 0)
-		die(_("Cannot get commit message for %s"),
-				sha1_to_hex(commit->object.sha1));
+		return error(_("Cannot get commit message for %s"),
+			sha1_to_hex(commit->object.sha1));
 
 	/*
 	 * "commit" is an existing commit.  We would want to apply
@@ -990,27 +976,28 @@ static int pick_revisions(struct replay_opts *opts)
 
 		walk_revs_populate_todo(&todo_list, opts);
 		if (create_seq_dir() < 0) {
-			fatal(_("A cherry-pick or revert is in progress."));
+			error(_("A cherry-pick or revert is in progress."));
 			advise(_("Use --continue to continue the operation"));
 			advise(_("or --reset to forget about it"));
-			exit(128);
+			return -1;
 		}
 		if (get_sha1("HEAD", sha1)) {
 			if (opts->action == REVERT)
-				die(_("Can't revert as initial commit"));
-			die(_("Can't cherry-pick into empty head"));
+				return error(_("Can't revert as initial commit"));
+			return error(_("Can't cherry-pick into empty head"));
 		}
 		save_head(sha1_to_hex(sha1));
 		save_opts(opts);
 	}
 	return pick_commits(todo_list, opts);
 error:
-	die(_("No %s in progress"), action_name(opts));
+	return error(_("No %s in progress"), action_name(opts));
 }
 
 int cmd_revert(int argc, const char **argv, const char *prefix)
 {
 	struct replay_opts opts;
+	int res;
 
 	memset(&opts, 0, sizeof(opts));
 	if (isatty(0))
@@ -1024,16 +1011,23 @@ int cmd_revert(int argc, const char **argv, const char *prefix)
 	 * cherry-pick should be handled differently from an existing
 	 * one that is being continued
 	 */
-	return pick_revisions(&opts);
+	res = pick_revisions(&opts);
+	if (res < 0)
+		die(_("revert failed"));
+	return res;
 }
 
 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 {
 	struct replay_opts opts;
+	int res;
 
 	memset(&opts, 0, sizeof(opts));
 	opts.action = CHERRY_PICK;
 	git_config(git_default_config, NULL);
 	parse_args(argc, argv, &opts);
-	return pick_revisions(&opts);
+	res = pick_revisions(&opts);
+	if (res < 0)
+		die(_("cherry-pick failed"));
+	return res;
 }
-- 
1.7.4.rc1.7.g2cf08.dirty

Re: [PATCH 00/18] Sequencer for inclusion v4

[Ramkumar Ramachandra]

Hi again,

Ramkumar Ramachandra writes:
> There were more style nits pointed out in v3: I learnt my lesson and
> ran checkpatch.pl this time.  Apart these minor stylistic changes, the
> other changes are:
> 1. Minor improvements to commit messages.
> 2. Tests now cleanup first, so one failing test doesn't take
> everything else down.
> 3. A rebase that moves "revert: Propogate errors upwards from
> do_pick_commit" to the end of the series.  A big thanks to Jonathan
> for performing the rebase for me.

And one more significant change:

4. read_populate_todo, read_populate_opts and dependent functions were
moved to the "revert: Introduce --continue to continue the operation"
patch, eliminating the need for the ugly MAYBE_UNUSED.

-- Ram