[PATCH 00/19] Implement the git add --patch backend in C

[PATCH 00/19] Implement the git add --patch backend in C

[Johannes Schindelin via GitGitGadget]

Out of all the patch series on the journey to provide git add --interactive 
and git add --patch in built-in versions, this is the big one, as can be
expected from the fact that the git add --patch functionality makes up over
half of the 1,800+ lines of git-add--interactive.perl.

The two patches that stick out are of course the ones to implement hunk
splitting and hunk editing: these operations are fundamentally more
complicated, and less obvious, than the entire rest of the operations.

Johannes Schindelin (19):
  built-in add -i: start implementing the `patch` functionality in C
  built-in add -i: wire up the new C code for the `patch` command
  built-in add -p: show colored hunks by default
  built-in add -p: adjust hunk headers as needed
  built-in add -p: color the prompt and the help text
  built-in add -p: offer a helpful error message when hunk navigation
    failed
  built-in add -p: support multi-file diffs
  built-in add -p: handle deleted empty files
  built-in app -p: allow selecting a mode change as a "hunk"
  built-in add -p: show different prompts for mode changes and deletions
  built-in add -p: implement the hunk splitting feature
  built-in add -p: coalesce hunks after splitting them
  strbuf: add a helper function to call the editor "on an strbuf"
  built-in add -p: implement hunk editing
  built-in add -p: implement the 'g' ("goto") command
  built-in add -p: implement the '/' ("search regex") command
  built-in add -p: implement the 'q' ("quit") command
  built-in add -p: only show the applicable parts of the help text
  built-in add -p: show helpful hint when nothing can be staged

 Makefile                   |    1 +
 add-interactive.c          |   29 +-
 add-interactive.h          |   19 +
 add-patch.c                | 1338 ++++++++++++++++++++++++++++++++++++
 builtin/add.c              |   15 +-
 strbuf.c                   |   28 +
 strbuf.h                   |   11 +
 t/t3701-add-interactive.sh |   42 ++
 8 files changed, 1464 insertions(+), 19 deletions(-)
 create mode 100644 add-patch.c


base-commit: b4bbbbd5a247e0e75d079bca591b657ec9084a46
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-173%2Fdscho%2Fadd-p-in-c-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-173/dscho/add-p-in-c-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/173
-- 
gitgitgadget

[PATCH 01/19] built-in add -i: start implementing the `patch` functionality in C

[Johannes Schindelin via GitGitGadget]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

In the previous steps, we re-implemented the main loop of `git add -i`
in C, and most of the commands.

Notably, we left out the actual functionality of `patch`, as the
relevant code makes up more than half of `git-add--interactive.perl`,
and is actually pretty independent of the rest of the commands.

With this commit, we start to tackle that `patch` part. For better
separation of concerns, we keep the code in a separate file,
`add-patch.c`. The new code is still guarded behind the
`add.interactive.useBuiltin` config setting, and for the moment,
it can only be called via `git add -p`.

The actual functionality follows the original implementation of
5cde71d64aff (git-add --interactive, 2006-12-10), but not too closely
(for example, we use string offsets rather than copying strings around,
and after seeing whether the `k` and `j` commands are applicable, in the
C version we remember which previous/next hunk was undecided, and use it
rather than looking again when the user asked to jump).

As a further deviation from that commit, We also use a comma instead of
a slash to separate the available commands in the prompt, as the current
version of the Perl script does this, and we also add a line about the
question mark ("print help") to the help text.

While it is tempting to use this conversion of `git add -p` as an excuse
to work on `apply_all_patches()` so that it does _not_ want to read a
file from `stdin` or from a file, but accepts, say, an `strbuf` instead,
we will refrain from this particular rabbit hole at this stage.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 Makefile          |   1 +
 add-interactive.h |   1 +
 add-patch.c       | 265 ++++++++++++++++++++++++++++++++++++++++++++++
 builtin/add.c     |  15 ++-
 4 files changed, 277 insertions(+), 5 deletions(-)
 create mode 100644 add-patch.c

diff --git a/Makefile b/Makefile
index 6c4a1e0ee5..0345d7408b 100644
--- a/Makefile
+++ b/Makefile
@@ -824,6 +824,7 @@ LIB_H := $(sort $(patsubst ./%,%,$(shell git ls-files '*.h' ':!t/' ':!Documentat
 
 LIB_OBJS += abspath.o
 LIB_OBJS += add-interactive.o
+LIB_OBJS += add-patch.o
 LIB_OBJS += advice.o
 LIB_OBJS += alias.o
 LIB_OBJS += alloc.o
diff --git a/add-interactive.h b/add-interactive.h
index 7043b8741d..0e3d93acc9 100644
--- a/add-interactive.h
+++ b/add-interactive.h
@@ -4,5 +4,6 @@
 struct repository;
 struct pathspec;
 int run_add_i(struct repository *r, const struct pathspec *ps);
+int run_add_p(struct repository *r, const struct pathspec *ps);
 
 #endif
diff --git a/add-patch.c b/add-patch.c
new file mode 100644
index 0000000000..d1b1a080e4
--- /dev/null
+++ b/add-patch.c
@@ -0,0 +1,265 @@
+#include "cache.h"
+#include "add-interactive.h"
+#include "strbuf.h"
+#include "run-command.h"
+#include "argv-array.h"
+#include "pathspec.h"
+
+struct hunk {
+	size_t start, end;
+	enum { UNDECIDED_HUNK = 0, SKIP_HUNK, USE_HUNK } use;
+};
+
+struct add_p_state {
+	struct repository *r;
+	struct strbuf answer, buf;
+
+	/* parsed diff */
+	struct strbuf plain;
+	struct hunk head;
+	struct hunk *hunk;
+	size_t hunk_nr, hunk_alloc;
+};
+
+static void setup_child_process(struct add_p_state *s,
+				struct child_process *cp, ...)
+{
+	va_list ap;
+	const char *arg;
+
+	va_start(ap, cp);
+	while ((arg = va_arg(ap, const char *)))
+		argv_array_push(&cp->args, arg);
+	va_end(ap);
+
+	cp->git_cmd = 1;
+	argv_array_pushf(&cp->env_array,
+			 INDEX_ENVIRONMENT "=%s", s->r->index_file);
+}
+
+static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
+{
+	struct strbuf *plain = &s->plain;
+	struct child_process cp = CHILD_PROCESS_INIT;
+	char *p, *pend;
+	size_t i;
+	struct hunk *hunk = NULL;
+	int res;
+
+	/* Use `--no-color` explicitly, just in case `diff.color = always`. */
+	setup_child_process(s, &cp,
+			 "diff-files", "-p", "--no-color", "--", NULL);
+	for (i = 0; i < ps->nr; i++)
+		argv_array_push(&cp.args, ps->items[i].original);
+
+	res = capture_command(&cp, plain, 0);
+	if (res)
+		return error(_("could not parse diff"));
+	if (!plain->len)
+		return 0;
+	strbuf_complete_line(plain);
+
+	/* parse hunks */
+	p = plain->buf;
+	pend = p + plain->len;
+	while (p != pend) {
+		char *eol = memchr(p, '\n', pend - p);
+		if (!eol)
+			eol = pend;
+
+		if (starts_with(p, "diff ")) {
+			if (p != plain->buf)
+				BUG("multi-file diff not yet handled");
+			hunk = &s->head;
+		} else if (p == plain->buf)
+			BUG("diff starts with unexpected line:\n"
+			    "%.*s\n", (int)(eol - p), p);
+		else if (starts_with(p, "@@ ")) {
+			s->hunk_nr++;
+			ALLOC_GROW(s->hunk, s->hunk_nr,
+				   s->hunk_alloc);
+			hunk = s->hunk + s->hunk_nr - 1;
+			memset(hunk, 0, sizeof(*hunk));
+
+			hunk->start = p - plain->buf;
+		}
+
+		p = eol == pend ? pend : eol + 1;
+		hunk->end = p - plain->buf;
+	}
+
+	return 0;
+}
+
+static void render_hunk(struct add_p_state *s, struct hunk *hunk,
+			struct strbuf *out)
+{
+	strbuf_add(out, s->plain.buf + hunk->start,
+		   hunk->end - hunk->start);
+}
+
+static void reassemble_patch(struct add_p_state *s, struct strbuf *out)
+{
+	struct hunk *hunk;
+	size_t i;
+
+	render_hunk(s, &s->head, out);
+
+	for (i = 0; i < s->hunk_nr; i++) {
+		hunk = s->hunk + i;
+		if (hunk->use == USE_HUNK)
+			render_hunk(s, hunk, out);
+	}
+}
+
+static const char help_patch_text[] =
+N_("y - stage this hunk\n"
+   "n - do not stage this hunk\n"
+   "a - stage this and all the remaining hunks\n"
+   "d - do not stage this hunk nor any of the remaining hunks\n"
+   "j - leave this hunk undecided, see next undecided hunk\n"
+   "J - leave this hunk undecided, see next hunk\n"
+   "k - leave this hunk undecided, see previous undecided hunk\n"
+   "K - leave this hunk undecided, see previous hunk\n"
+   "? - print help\n");
+
+static int patch_update_file(struct add_p_state *s)
+{
+	size_t hunk_index = 0;
+	ssize_t i, undecided_previous, undecided_next;
+	struct hunk *hunk;
+	char ch;
+	struct child_process cp = CHILD_PROCESS_INIT;
+
+	if (!s->hunk_nr)
+		return 0;
+
+	strbuf_reset(&s->buf);
+	render_hunk(s, &s->head, &s->buf);
+	fputs(s->buf.buf, stdout);
+	for (;;) {
+		if (hunk_index >= s->hunk_nr)
+			hunk_index = 0;
+		hunk = s->hunk + hunk_index;
+
+		undecided_previous = -1;
+		for (i = hunk_index - 1; i >= 0; i--)
+			if (s->hunk[i].use == UNDECIDED_HUNK) {
+				undecided_previous = i;
+				break;
+			}
+
+		undecided_next = -1;
+		for (i = hunk_index + 1; i < s->hunk_nr; i++)
+			if (s->hunk[i].use == UNDECIDED_HUNK) {
+				undecided_next = i;
+				break;
+			}
+
+		/* Everything decided? */
+		if (undecided_previous < 0 && undecided_next < 0 &&
+		    hunk->use != UNDECIDED_HUNK)
+			break;
+
+		strbuf_reset(&s->buf);
+		render_hunk(s, hunk, &s->buf);
+		fputs(s->buf.buf, stdout);
+
+		strbuf_reset(&s->buf);
+		if (undecided_previous >= 0)
+			strbuf_addstr(&s->buf, ",k");
+		if (hunk_index)
+			strbuf_addstr(&s->buf, ",K");
+		if (undecided_next >= 0)
+			strbuf_addstr(&s->buf, ",j");
+		if (hunk_index + 1 < s->hunk_nr)
+			strbuf_addstr(&s->buf, ",J");
+		printf("(%"PRIuMAX"/%"PRIuMAX") ",
+		       (uintmax_t)hunk_index + 1, (uintmax_t)s->hunk_nr);
+		printf(_("Stage this hunk [y,n,a,d%s,?]? "), s->buf.buf);
+		fflush(stdout);
+		if (strbuf_getline(&s->answer, stdin) == EOF)
+			break;
+		strbuf_trim_trailing_newline(&s->answer);
+
+		if (!s->answer.len)
+			continue;
+		ch = tolower(s->answer.buf[0]);
+		if (ch == 'y') {
+			hunk->use = USE_HUNK;
+soft_increment:
+			hunk_index = undecided_next < 0 ?
+				s->hunk_nr : undecided_next;
+		} else if (ch == 'n') {
+			hunk->use = SKIP_HUNK;
+			goto soft_increment;
+		} else if (ch == 'a') {
+			for (; hunk_index < s->hunk_nr; hunk_index++) {
+				hunk = s->hunk + hunk_index;
+				if (hunk->use == UNDECIDED_HUNK)
+					hunk->use = USE_HUNK;
+			}
+		} else if (ch == 'd') {
+			for (; hunk_index < s->hunk_nr; hunk_index++) {
+				hunk = s->hunk + hunk_index;
+				if (hunk->use == UNDECIDED_HUNK)
+					hunk->use = SKIP_HUNK;
+			}
+		} else if (hunk_index && s->answer.buf[0] == 'K')
+			hunk_index--;
+		else if (hunk_index + 1 < s->hunk_nr &&
+			 s->answer.buf[0] == 'J')
+			hunk_index++;
+		else if (undecided_previous >= 0 &&
+			 s->answer.buf[0] == 'k')
+			hunk_index = undecided_previous;
+		else if (undecided_next >= 0 && s->answer.buf[0] == 'j')
+			hunk_index = undecided_next;
+		else
+			puts(_(help_patch_text));
+	}
+
+	/* Any hunk to be used? */
+	for (i = 0; i < s->hunk_nr; i++)
+		if (s->hunk[i].use == USE_HUNK)
+			break;
+
+	if (i < s->hunk_nr) {
+		/* At least one hunk selected: apply */
+		strbuf_reset(&s->buf);
+		reassemble_patch(s, &s->buf);
+
+		discard_index(s->r->index);
+		setup_child_process(s, &cp, "apply", "--cached", NULL);
+		if (pipe_command(&cp, s->buf.buf, s->buf.len,
+				 NULL, 0, NULL, 0))
+			error(_("'git apply --cached' failed"));
+		if (!repo_read_index(s->r))
+			repo_refresh_and_write_index(s->r, REFRESH_QUIET, 0,
+						     1, NULL, NULL, NULL);
+	}
+
+	putchar('\n');
+	return 0;
+}
+
+int run_add_p(struct repository *r, const struct pathspec *ps)
+{
+	struct add_p_state s = { r, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT };
+
+	if (discard_index(r->index) < 0 || repo_read_index(r) < 0 ||
+	    repo_refresh_and_write_index(r, REFRESH_QUIET, 0, 1,
+					 NULL, NULL, NULL) < 0 ||
+	    parse_diff(&s, ps) < 0) {
+		strbuf_release(&s.plain);
+		return -1;
+	}
+
+	if (s.hunk_nr)
+		patch_update_file(&s);
+
+	strbuf_release(&s.answer);
+	strbuf_release(&s.buf);
+	strbuf_release(&s.plain);
+	return 0;
+}
diff --git a/builtin/add.c b/builtin/add.c
index d4686d5218..1deb59a642 100644
--- a/builtin/add.c
+++ b/builtin/add.c
@@ -189,12 +189,17 @@ int run_add_interactive(const char *revision, const char *patch_mode,
 	int use_builtin_add_i =
 		git_env_bool("GIT_TEST_ADD_I_USE_BUILTIN", -1);
 
-	if (!patch_mode) {
-		if (use_builtin_add_i < 0)
-			git_config_get_bool("add.interactive.usebuiltin",
-					    &use_builtin_add_i);
-		if (use_builtin_add_i == 1)
+	if (use_builtin_add_i < 0)
+		git_config_get_bool("add.interactive.usebuiltin",
+				    &use_builtin_add_i);
+
+	if (use_builtin_add_i == 1) {
+		if (!patch_mode)
 			return !!run_add_i(the_repository, pathspec);
+		if (strcmp(patch_mode, "--patch"))
+			die("'%s' not yet supported in the built-in add -p",
+			    patch_mode);
+		return !!run_add_p(the_repository, pathspec);
 	}
 
 	argv_array_push(&argv, "add--interactive");
-- 
gitgitgadget

[PATCH 02/19] built-in add -i: wire up the new C code for the `patch` command

[Johannes Schindelin via GitGitGadget]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

The code in `git-add--interactive.perl` that takes care of the `patch`
command can look quite intimidating. There are so many modes in which it
can be called, for example.

But for the `patch` command in `git add -i`, only one mode is relevant:
the `stage` mode. And we just implemented the beginnings of that mode in
C so far. So let's use it when `add.interactive.useBuiltin=true`.

Now, while the code in `add-patch.c` is far from reaching feature parity
with the code in `git-add--interactive.perl` (color is not implemented,
the diff algorithm cannot be configured, the colored diff cannot be
post-processed via `interactive.diffFilter`, many commands are
unimplemented yet, etc), hooking it all up with the part of `git add -i`
that is already converted to C makes it easier to test and develop it.

Note: at this stage, both the `add.interactive.useBuiltin` config
setting is still safely opt-in, and will probably be fore quite some
time, to allow for thorough testing "in the wild" without adversely
affecting existing users.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 add-interactive.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/add-interactive.c b/add-interactive.c
index f395d54c08..034c1dc02f 100644
--- a/add-interactive.c
+++ b/add-interactive.c
@@ -917,15 +917,18 @@ static int run_patch(struct add_i_state *s, const struct pathspec *ps,
 	count = list_and_choose(s, files, opts);
 	if (count >= 0) {
 		struct argv_array args = ARGV_ARRAY_INIT;
+		struct pathspec ps_selected = { 0 };
 
-		argv_array_pushl(&args, "git", "add--interactive", "--patch",
-				 "--", NULL);
 		for (i = 0; i < files->items.nr; i++)
 			if (files->selected[i])
 				argv_array_push(&args,
 						files->items.items[i].string);
-		res = run_command_v_opt(args.argv, 0);
+		parse_pathspec(&ps_selected,
+			       PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
+			       PATHSPEC_LITERAL_PATH, "", args.argv);
+		res = run_add_p(s->r, &ps_selected);
 		argv_array_clear(&args);
+		clear_pathspec(&ps_selected);
 	}
 
 	return res;
-- 
gitgitgadget

[PATCH 03/19] built-in add -p: show colored hunks by default

[Johannes Schindelin via GitGitGadget]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

Just like the Perl version, we now generate two diffs if `color.diff` is
set: one with and one without color. Then we parse them in parallel and
record which hunks start at which offsets in both.

Note that this is a (slight) deviation from the way the Perl version did
it: we are no longer reading the output of `diff-files` line by line
(which is more natural for Perl than for C), but in one go, and parse
everything later, so we might just as well do it in synchrony.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 add-patch.c | 79 +++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 62 insertions(+), 17 deletions(-)

diff --git a/add-patch.c b/add-patch.c
index d1b1a080e4..79eefa9505 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -4,9 +4,10 @@
 #include "run-command.h"
 #include "argv-array.h"
 #include "pathspec.h"
+#include "color.h"
 
 struct hunk {
-	size_t start, end;
+	size_t start, end, colored_start, colored_end;
 	enum { UNDECIDED_HUNK = 0, SKIP_HUNK, USE_HUNK } use;
 };
 
@@ -15,7 +16,7 @@ struct add_p_state {
 	struct strbuf answer, buf;
 
 	/* parsed diff */
-	struct strbuf plain;
+	struct strbuf plain, colored;
 	struct hunk head;
 	struct hunk *hunk;
 	size_t hunk_nr, hunk_alloc;
@@ -39,26 +40,50 @@ static void setup_child_process(struct add_p_state *s,
 
 static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 {
-	struct strbuf *plain = &s->plain;
+	struct argv_array args = ARGV_ARRAY_INIT;
+	struct strbuf *plain = &s->plain, *colored = NULL;
 	struct child_process cp = CHILD_PROCESS_INIT;
-	char *p, *pend;
-	size_t i;
+	char *p, *pend, *colored_p = NULL, *colored_pend = NULL;
+	size_t i, color_arg_index;
 	struct hunk *hunk = NULL;
 	int res;
 
 	/* Use `--no-color` explicitly, just in case `diff.color = always`. */
-	setup_child_process(s, &cp,
-			 "diff-files", "-p", "--no-color", "--", NULL);
+	argv_array_pushl(&args, "diff-files", "-p", "--no-color", "--", NULL);
+	color_arg_index = args.argc - 2;
 	for (i = 0; i < ps->nr; i++)
-		argv_array_push(&cp.args, ps->items[i].original);
+		argv_array_push(&args, ps->items[i].original);
 
+	setup_child_process(s, &cp, NULL);
+	cp.argv = args.argv;
 	res = capture_command(&cp, plain, 0);
-	if (res)
+	if (res) {
+		argv_array_clear(&args);
 		return error(_("could not parse diff"));
-	if (!plain->len)
+	}
+	if (!plain->len) {
+		argv_array_clear(&args);
 		return 0;
+	}
 	strbuf_complete_line(plain);
 
+	if (want_color_fd(1, -1)) {
+		struct child_process colored_cp = CHILD_PROCESS_INIT;
+
+		setup_child_process(s, &colored_cp, NULL);
+		xsnprintf((char *)args.argv[color_arg_index], 8, "--color");
+		colored_cp.argv = args.argv;
+		colored = &s->colored;
+		res = capture_command(&colored_cp, colored, 0);
+		argv_array_clear(&args);
+		if (res)
+			return error(_("could not parse colored diff"));
+		strbuf_complete_line(colored);
+		colored_p = colored->buf;
+		colored_pend = colored_p + colored->len;
+	}
+	argv_array_clear(&args);
+
 	/* parse hunks */
 	p = plain->buf;
 	pend = p + plain->len;
@@ -82,20 +107,37 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 			memset(hunk, 0, sizeof(*hunk));
 
 			hunk->start = p - plain->buf;
+			if (colored)
+				hunk->colored_start = colored_p - colored->buf;
 		}
 
 		p = eol == pend ? pend : eol + 1;
 		hunk->end = p - plain->buf;
+
+		if (colored) {
+			char *colored_eol = memchr(colored_p, '\n',
+						   colored_pend - colored_p);
+			if (colored_eol)
+				colored_p = colored_eol + 1;
+			else
+				colored_p = colored_pend;
+
+			hunk->colored_end = colored_p - colored->buf;
+		}
 	}
 
 	return 0;
 }
 
 static void render_hunk(struct add_p_state *s, struct hunk *hunk,
-			struct strbuf *out)
+			int colored, struct strbuf *out)
 {
-	strbuf_add(out, s->plain.buf + hunk->start,
-		   hunk->end - hunk->start);
+	if (colored)
+		strbuf_add(out, s->colored.buf + hunk->colored_start,
+			   hunk->colored_end - hunk->colored_start);
+	else
+		strbuf_add(out, s->plain.buf + hunk->start,
+			   hunk->end - hunk->start);
 }
 
 static void reassemble_patch(struct add_p_state *s, struct strbuf *out)
@@ -103,12 +145,12 @@ static void reassemble_patch(struct add_p_state *s, struct strbuf *out)
 	struct hunk *hunk;
 	size_t i;
 
-	render_hunk(s, &s->head, out);
+	render_hunk(s, &s->head, 0, out);
 
 	for (i = 0; i < s->hunk_nr; i++) {
 		hunk = s->hunk + i;
 		if (hunk->use == USE_HUNK)
-			render_hunk(s, hunk, out);
+			render_hunk(s, hunk, 0, out);
 	}
 }
 
@@ -130,12 +172,13 @@ static int patch_update_file(struct add_p_state *s)
 	struct hunk *hunk;
 	char ch;
 	struct child_process cp = CHILD_PROCESS_INIT;
+	int colored = !!s->colored.len;
 
 	if (!s->hunk_nr)
 		return 0;
 
 	strbuf_reset(&s->buf);
-	render_hunk(s, &s->head, &s->buf);
+	render_hunk(s, &s->head, colored, &s->buf);
 	fputs(s->buf.buf, stdout);
 	for (;;) {
 		if (hunk_index >= s->hunk_nr)
@@ -162,7 +205,7 @@ static int patch_update_file(struct add_p_state *s)
 			break;
 
 		strbuf_reset(&s->buf);
-		render_hunk(s, hunk, &s->buf);
+		render_hunk(s, hunk, colored, &s->buf);
 		fputs(s->buf.buf, stdout);
 
 		strbuf_reset(&s->buf);
@@ -252,6 +295,7 @@ int run_add_p(struct repository *r, const struct pathspec *ps)
 					 NULL, NULL, NULL) < 0 ||
 	    parse_diff(&s, ps) < 0) {
 		strbuf_release(&s.plain);
+		strbuf_release(&s.colored);
 		return -1;
 	}
 
@@ -261,5 +305,6 @@ int run_add_p(struct repository *r, const struct pathspec *ps)
 	strbuf_release(&s.answer);
 	strbuf_release(&s.buf);
 	strbuf_release(&s.plain);
+	strbuf_release(&s.colored);
 	return 0;
 }
-- 
gitgitgadget

[PATCH 04/19] built-in add -p: adjust hunk headers as needed

[Johannes Schindelin via GitGitGadget]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

When skipping a hunk that adds a different number of lines than it
removes, we need to adjust the subsequent hunk headers of non-skipped
hunks: in pathological cases, the context is not enough to determine
precisely where the patch should be applied.

This problem was identified in 23fea4c240 (t3701: add failing test for
pathological context lines, 2018-03-01) and fixed in the Perl version in
fecc6f3a68 (add -p: adjust offsets of subsequent hunks when one is
skipped, 2018-03-01).

And this patch fixes it in the C version of `git add -p`.

In contrast to the Perl version, we try to keep the extra text on the
hunk header (which typically contains the signature of the function
whose code is changed in the hunk) intact.

Note: while the C version does not support staging mode changes at this
stage, we already prepare for this by simply skipping the hunk header if
both old and new offset is 0 (this cannot happen for regular hunks, and
we will use this as an indicator that we are looking at a special hunk).

Likewise, we already prepare for hunk splitting by handling the absence
of extra text in the hunk header gracefully: only the first split hunk
will have that text, the others will not (indicated by an empty extra
text start/end range). Preparing for hunk splitting already at this
stage avoids an indentation change of the entire hunk header-printing
block later, and is almost as easy to review as without that handling.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 add-interactive.c |  14 +----
 add-interactive.h |  15 +++++
 add-patch.c       | 145 ++++++++++++++++++++++++++++++++++++++++++----
 3 files changed, 151 insertions(+), 23 deletions(-)

diff --git a/add-interactive.c b/add-interactive.c
index 034c1dc02f..29356c5aa2 100644
--- a/add-interactive.c
+++ b/add-interactive.c
@@ -10,16 +10,6 @@
 #include "dir.h"
 #include "run-command.h"
 
-struct add_i_state {
-	struct repository *r;
-	int use_color;
-	char header_color[COLOR_MAXLEN];
-	char help_color[COLOR_MAXLEN];
-	char prompt_color[COLOR_MAXLEN];
-	char error_color[COLOR_MAXLEN];
-	char reset_color[COLOR_MAXLEN];
-};
-
 static void init_color(struct repository *r, struct add_i_state *s,
 		       const char *slot_name, char *dst,
 		       const char *default_color)
@@ -36,7 +26,7 @@ static void init_color(struct repository *r, struct add_i_state *s,
 	free(key);
 }
 
-static void init_add_i_state(struct add_i_state *s, struct repository *r)
+void init_add_i_state(struct add_i_state *s, struct repository *r)
 {
 	const char *value;
 
@@ -54,6 +44,8 @@ static void init_add_i_state(struct add_i_state *s, struct repository *r)
 	init_color(r, s, "prompt", s->prompt_color, GIT_COLOR_BOLD_BLUE);
 	init_color(r, s, "error", s->error_color, GIT_COLOR_BOLD_RED);
 	init_color(r, s, "reset", s->reset_color, GIT_COLOR_RESET);
+	init_color(r, s, "fraginfo", s->fraginfo_color,
+		   diff_get_color(s->use_color, DIFF_FRAGINFO));
 }
 
 /*
diff --git a/add-interactive.h b/add-interactive.h
index 0e3d93acc9..584f304a9a 100644
--- a/add-interactive.h
+++ b/add-interactive.h
@@ -1,6 +1,21 @@
 #ifndef ADD_INTERACTIVE_H
 #define ADD_INTERACTIVE_H
 
+#include "color.h"
+
+struct add_i_state {
+	struct repository *r;
+	int use_color;
+	char header_color[COLOR_MAXLEN];
+	char help_color[COLOR_MAXLEN];
+	char prompt_color[COLOR_MAXLEN];
+	char error_color[COLOR_MAXLEN];
+	char reset_color[COLOR_MAXLEN];
+	char fraginfo_color[COLOR_MAXLEN];
+};
+
+void init_add_i_state(struct add_i_state *s, struct repository *r);
+
 struct repository;
 struct pathspec;
 int run_add_i(struct repository *r, const struct pathspec *ps);
diff --git a/add-patch.c b/add-patch.c
index 79eefa9505..e266a96ca7 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -5,14 +5,26 @@
 #include "argv-array.h"
 #include "pathspec.h"
 #include "color.h"
+#include "diff.h"
+
+struct hunk_header {
+	unsigned long old_offset, old_count, new_offset, new_count;
+	/*
+	 * Start/end offsets to the extra text after the second `@@` in the
+	 * hunk header, e.g. the function signature. This is expected to
+	 * include the newline.
+	 */
+	size_t extra_start, extra_end, colored_extra_start, colored_extra_end;
+};
 
 struct hunk {
 	size_t start, end, colored_start, colored_end;
 	enum { UNDECIDED_HUNK = 0, SKIP_HUNK, USE_HUNK } use;
+	struct hunk_header header;
 };
 
 struct add_p_state {
-	struct repository *r;
+	struct add_i_state s;
 	struct strbuf answer, buf;
 
 	/* parsed diff */
@@ -35,7 +47,70 @@ static void setup_child_process(struct add_p_state *s,
 
 	cp->git_cmd = 1;
 	argv_array_pushf(&cp->env_array,
-			 INDEX_ENVIRONMENT "=%s", s->r->index_file);
+			 INDEX_ENVIRONMENT "=%s", s->s.r->index_file);
+}
+
+static int parse_range(const char **p,
+		       unsigned long *offset, unsigned long *count)
+{
+	char *pend;
+
+	*offset = strtoul(*p, &pend, 10);
+	if (pend == *p)
+		return -1;
+	if (*pend != ',') {
+		*count = 1;
+		*p = pend;
+		return 0;
+	}
+	*count = strtoul(pend + 1, (char **)p, 10);
+	return *p == pend + 1 ? -1 : 0;
+}
+
+static int parse_hunk_header(struct add_p_state *s, struct hunk *hunk)
+{
+	struct hunk_header *header = &hunk->header;
+	const char *line = s->plain.buf + hunk->start, *p = line;
+	char *eol = memchr(p, '\n', s->plain.len - hunk->start);
+
+	if (!eol)
+		eol = s->plain.buf + s->plain.len;
+
+	if (!skip_prefix(p, "@@ -", &p) ||
+	    parse_range(&p, &header->old_offset, &header->old_count) < 0 ||
+	    !skip_prefix(p, " +", &p) ||
+	    parse_range(&p, &header->new_offset, &header->new_count) < 0 ||
+	    !skip_prefix(p, " @@", &p))
+		return error(_("could not parse hunk header '%.*s'"),
+			     (int)(eol - line), line);
+
+	hunk->start = eol - s->plain.buf + (*eol == '\n');
+	header->extra_start = p - s->plain.buf;
+	header->extra_end = hunk->start;
+
+	if (!s->colored.len) {
+		header->colored_extra_start = header->colored_extra_end = 0;
+		return 0;
+	}
+
+	/* Now find the extra text in the colored diff */
+	line = s->colored.buf + hunk->colored_start;
+	eol = memchr(line, '\n', s->colored.len - hunk->colored_start);
+	if (!eol)
+		eol = s->colored.buf + s->colored.len;
+	p = memmem(line, eol - line, "@@ -", 4);
+	if (!p)
+		return error(_("could not parse colored hunk header '%.*s'"),
+			     (int)(eol - line), line);
+	p = memmem(p + 4, eol - p - 4, " @@", 3);
+	if (!p)
+		return error(_("could not parse colored hunk header '%.*s'"),
+			     (int)(eol - line), line);
+	hunk->colored_start = eol - s->colored.buf + (*eol == '\n');
+	header->colored_extra_start = p + 3 - s->colored.buf;
+	header->colored_extra_end = hunk->colored_start;
+
+	return 0;
 }
 
 static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
@@ -109,6 +184,9 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 			hunk->start = p - plain->buf;
 			if (colored)
 				hunk->colored_start = colored_p - colored->buf;
+
+			if (parse_hunk_header(s, hunk) < 0)
+				return -1;
 		}
 
 		p = eol == pend ? pend : eol + 1;
@@ -130,8 +208,43 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 }
 
 static void render_hunk(struct add_p_state *s, struct hunk *hunk,
-			int colored, struct strbuf *out)
+			ssize_t delta, int colored, struct strbuf *out)
 {
+	struct hunk_header *header = &hunk->header;
+
+	if (hunk->header.old_offset != 0 || hunk->header.new_offset != 0) {
+		/*
+		 * Generate the hunk header dynamically, except for special
+		 * hunks (such as the diff header).
+		 */
+		const char *p;
+		size_t len;
+		unsigned long old_offset = header->old_offset;
+		unsigned long new_offset = header->new_offset;
+
+		if (!colored) {
+			p = s->plain.buf + header->extra_start;
+			len = header->extra_end - header->extra_start;
+		} else {
+			strbuf_addstr(out, s->s.fraginfo_color);
+			p = s->colored.buf + header->colored_extra_start;
+			len = header->colored_extra_end
+				- header->colored_extra_start;
+		}
+
+		new_offset += delta;
+
+		strbuf_addf(out, "@@ -%lu,%lu +%lu,%lu @@",
+			    old_offset, header->old_count,
+			    new_offset, header->new_count);
+		if (len)
+			strbuf_add(out, p, len);
+		else if (colored)
+			strbuf_addf(out, "%s\n", GIT_COLOR_RESET);
+		else
+			strbuf_addch(out, '\n');
+	}
+
 	if (colored)
 		strbuf_add(out, s->colored.buf + hunk->colored_start,
 			   hunk->colored_end - hunk->colored_start);
@@ -144,13 +257,17 @@ static void reassemble_patch(struct add_p_state *s, struct strbuf *out)
 {
 	struct hunk *hunk;
 	size_t i;
+	ssize_t delta = 0;
 
-	render_hunk(s, &s->head, 0, out);
+	render_hunk(s, &s->head, 0, 0, out);
 
 	for (i = 0; i < s->hunk_nr; i++) {
 		hunk = s->hunk + i;
-		if (hunk->use == USE_HUNK)
-			render_hunk(s, hunk, 0, out);
+		if (hunk->use != USE_HUNK)
+			delta += hunk->header.old_count
+				- hunk->header.new_count;
+		else
+			render_hunk(s, hunk, delta, 0, out);
 	}
 }
 
@@ -178,7 +295,7 @@ static int patch_update_file(struct add_p_state *s)
 		return 0;
 
 	strbuf_reset(&s->buf);
-	render_hunk(s, &s->head, colored, &s->buf);
+	render_hunk(s, &s->head, 0, colored, &s->buf);
 	fputs(s->buf.buf, stdout);
 	for (;;) {
 		if (hunk_index >= s->hunk_nr)
@@ -205,7 +322,7 @@ static int patch_update_file(struct add_p_state *s)
 			break;
 
 		strbuf_reset(&s->buf);
-		render_hunk(s, hunk, colored, &s->buf);
+		render_hunk(s, hunk, 0, colored, &s->buf);
 		fputs(s->buf.buf, stdout);
 
 		strbuf_reset(&s->buf);
@@ -272,13 +389,13 @@ static int patch_update_file(struct add_p_state *s)
 		strbuf_reset(&s->buf);
 		reassemble_patch(s, &s->buf);
 
-		discard_index(s->r->index);
+		discard_index(s->s.r->index);
 		setup_child_process(s, &cp, "apply", "--cached", NULL);
 		if (pipe_command(&cp, s->buf.buf, s->buf.len,
 				 NULL, 0, NULL, 0))
 			error(_("'git apply --cached' failed"));
-		if (!repo_read_index(s->r))
-			repo_refresh_and_write_index(s->r, REFRESH_QUIET, 0,
+		if (!repo_read_index(s->s.r))
+			repo_refresh_and_write_index(s->s.r, REFRESH_QUIET, 0,
 						     1, NULL, NULL, NULL);
 	}
 
@@ -288,7 +405,11 @@ static int patch_update_file(struct add_p_state *s)
 
 int run_add_p(struct repository *r, const struct pathspec *ps)
 {
-	struct add_p_state s = { r, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT };
+	struct add_p_state s = {
+		{ r }, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT
+	};
+
+	init_add_i_state(&s.s, r);
 
 	if (discard_index(r->index) < 0 || repo_read_index(r) < 0 ||
 	    repo_refresh_and_write_index(r, REFRESH_QUIET, 0, 1,
-- 
gitgitgadget

[PATCH 05/19] built-in add -p: color the prompt and the help text

[Johannes Schindelin via GitGitGadget]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

... just like the Perl version ;-)

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 add-patch.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/add-patch.c b/add-patch.c
index e266a96ca7..dab2ff2381 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -334,9 +334,12 @@ static int patch_update_file(struct add_p_state *s)
 			strbuf_addstr(&s->buf, ",j");
 		if (hunk_index + 1 < s->hunk_nr)
 			strbuf_addstr(&s->buf, ",J");
-		printf("(%"PRIuMAX"/%"PRIuMAX") ",
-		       (uintmax_t)hunk_index + 1, (uintmax_t)s->hunk_nr);
-		printf(_("Stage this hunk [y,n,a,d%s,?]? "), s->buf.buf);
+		color_fprintf(stdout, s->s.prompt_color,
+			      "(%"PRIuMAX"/%"PRIuMAX") ",
+			      (uintmax_t)hunk_index + 1, (uintmax_t)s->hunk_nr);
+		color_fprintf(stdout, s->s.prompt_color,
+			      _("Stage this hunk [y,n,a,d%s,?]? "),
+			      s->buf.buf);
 		fflush(stdout);
 		if (strbuf_getline(&s->answer, stdin) == EOF)
 			break;
@@ -376,7 +379,8 @@ static int patch_update_file(struct add_p_state *s)
 		else if (undecided_next >= 0 && s->answer.buf[0] == 'j')
 			hunk_index = undecided_next;
 		else
-			puts(_(help_patch_text));
+			color_fprintf(stdout, s->s.help_color,
+				      _(help_patch_text));
 	}
 
 	/* Any hunk to be used? */
-- 
gitgitgadget

[PATCH 06/19] built-in add -p: offer a helpful error message when hunk navigation failed

[Johannes Schindelin via GitGitGadget]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

... just like the Perl version currently does...

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 add-patch.c | 44 +++++++++++++++++++++++++++++++++-----------
 1 file changed, 33 insertions(+), 11 deletions(-)

diff --git a/add-patch.c b/add-patch.c
index dab2ff2381..f59471cdf2 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -34,6 +34,18 @@ struct add_p_state {
 	size_t hunk_nr, hunk_alloc;
 };
 
+static void err(struct add_p_state *s, const char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	fputs(s->s.error_color, stderr);
+	vfprintf(stderr, fmt, args);
+	fputs(s->s.reset_color, stderr);
+	fputc('\n', stderr);
+	va_end(args);
+}
+
 static void setup_child_process(struct add_p_state *s,
 				struct child_process *cp, ...)
 {
@@ -368,17 +380,27 @@ static int patch_update_file(struct add_p_state *s)
 				if (hunk->use == UNDECIDED_HUNK)
 					hunk->use = SKIP_HUNK;
 			}
-		} else if (hunk_index && s->answer.buf[0] == 'K')
-			hunk_index--;
-		else if (hunk_index + 1 < s->hunk_nr &&
-			 s->answer.buf[0] == 'J')
-			hunk_index++;
-		else if (undecided_previous >= 0 &&
-			 s->answer.buf[0] == 'k')
-			hunk_index = undecided_previous;
-		else if (undecided_next >= 0 && s->answer.buf[0] == 'j')
-			hunk_index = undecided_next;
-		else
+		} else if (s->answer.buf[0] == 'K') {
+			if (hunk_index)
+				hunk_index--;
+			else
+				err(s, _("No previous hunk"));
+		} else if (s->answer.buf[0] == 'J') {
+			if (hunk_index + 1 < s->hunk_nr)
+				hunk_index++;
+			else
+				err(s, _("No next hunk"));
+		} else if (s->answer.buf[0] == 'k') {
+			if (undecided_previous >= 0)
+				hunk_index = undecided_previous;
+			else
+				err(s, _("No previous hunk"));
+		} else if (s->answer.buf[0] == 'j') {
+			if (undecided_next >= 0)
+				hunk_index = undecided_next;
+			else
+				err(s, _("No next hunk"));
+		} else
 			color_fprintf(stdout, s->s.help_color,
 				      _(help_patch_text));
 	}
-- 
gitgitgadget

[PATCH 07/19] built-in add -p: support multi-file diffs

[Johannes Schindelin via GitGitGadget]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

For simplicity, the initial implementation in C handled only a single
modified file. Now it handles an arbitrary number of files.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 add-patch.c | 91 +++++++++++++++++++++++++++++++----------------------
 1 file changed, 53 insertions(+), 38 deletions(-)

diff --git a/add-patch.c b/add-patch.c
index f59471cdf2..7c1b3b3935 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -29,9 +29,12 @@ struct add_p_state {
 
 	/* parsed diff */
 	struct strbuf plain, colored;
-	struct hunk head;
-	struct hunk *hunk;
-	size_t hunk_nr, hunk_alloc;
+	struct file_diff {
+		struct hunk head;
+		struct hunk *hunk;
+		size_t hunk_nr, hunk_alloc;
+	} *file_diff;
+	size_t file_diff_nr;
 };
 
 static void err(struct add_p_state *s, const char *fmt, ...)
@@ -131,7 +134,8 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 	struct strbuf *plain = &s->plain, *colored = NULL;
 	struct child_process cp = CHILD_PROCESS_INIT;
 	char *p, *pend, *colored_p = NULL, *colored_pend = NULL;
-	size_t i, color_arg_index;
+	size_t file_diff_alloc = 0, i, color_arg_index;
+	struct file_diff *file_diff = NULL;
 	struct hunk *hunk = NULL;
 	int res;
 
@@ -171,7 +175,7 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 	}
 	argv_array_clear(&args);
 
-	/* parse hunks */
+	/* parse files and hunks */
 	p = plain->buf;
 	pend = p + plain->len;
 	while (p != pend) {
@@ -180,17 +184,23 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 			eol = pend;
 
 		if (starts_with(p, "diff ")) {
-			if (p != plain->buf)
-				BUG("multi-file diff not yet handled");
-			hunk = &s->head;
+			s->file_diff_nr++;
+			ALLOC_GROW(s->file_diff, s->file_diff_nr,
+				   file_diff_alloc);
+			file_diff = s->file_diff + s->file_diff_nr - 1;
+			memset(file_diff, 0, sizeof(*file_diff));
+			hunk = &file_diff->head;
+			hunk->start = p - plain->buf;
+			if (colored_p)
+				hunk->colored_start = colored_p - colored->buf;
 		} else if (p == plain->buf)
 			BUG("diff starts with unexpected line:\n"
 			    "%.*s\n", (int)(eol - p), p);
 		else if (starts_with(p, "@@ ")) {
-			s->hunk_nr++;
-			ALLOC_GROW(s->hunk, s->hunk_nr,
-				   s->hunk_alloc);
-			hunk = s->hunk + s->hunk_nr - 1;
+			file_diff->hunk_nr++;
+			ALLOC_GROW(file_diff->hunk, file_diff->hunk_nr,
+				   file_diff->hunk_alloc);
+			hunk = file_diff->hunk + file_diff->hunk_nr - 1;
 			memset(hunk, 0, sizeof(*hunk));
 
 			hunk->start = p - plain->buf;
@@ -265,16 +275,17 @@ static void render_hunk(struct add_p_state *s, struct hunk *hunk,
 			   hunk->end - hunk->start);
 }
 
-static void reassemble_patch(struct add_p_state *s, struct strbuf *out)
+static void reassemble_patch(struct add_p_state *s,
+			     struct file_diff *file_diff, struct strbuf *out)
 {
 	struct hunk *hunk;
 	size_t i;
 	ssize_t delta = 0;
 
-	render_hunk(s, &s->head, 0, 0, out);
+	render_hunk(s, &file_diff->head, 0, 0, out);
 
-	for (i = 0; i < s->hunk_nr; i++) {
-		hunk = s->hunk + i;
+	for (i = 0; i < file_diff->hunk_nr; i++) {
+		hunk = file_diff->hunk + i;
 		if (hunk->use != USE_HUNK)
 			delta += hunk->header.old_count
 				- hunk->header.new_count;
@@ -294,7 +305,8 @@ N_("y - stage this hunk\n"
    "K - leave this hunk undecided, see previous hunk\n"
    "? - print help\n");
 
-static int patch_update_file(struct add_p_state *s)
+static int patch_update_file(struct add_p_state *s,
+			     struct file_diff *file_diff)
 {
 	size_t hunk_index = 0;
 	ssize_t i, undecided_previous, undecided_next;
@@ -303,27 +315,27 @@ static int patch_update_file(struct add_p_state *s)
 	struct child_process cp = CHILD_PROCESS_INIT;
 	int colored = !!s->colored.len;
 
-	if (!s->hunk_nr)
+	if (!file_diff->hunk_nr)
 		return 0;
 
 	strbuf_reset(&s->buf);
-	render_hunk(s, &s->head, 0, colored, &s->buf);
+	render_hunk(s, &file_diff->head, 0, colored, &s->buf);
 	fputs(s->buf.buf, stdout);
 	for (;;) {
-		if (hunk_index >= s->hunk_nr)
+		if (hunk_index >= file_diff->hunk_nr)
 			hunk_index = 0;
-		hunk = s->hunk + hunk_index;
+		hunk = file_diff->hunk + hunk_index;
 
 		undecided_previous = -1;
 		for (i = hunk_index - 1; i >= 0; i--)
-			if (s->hunk[i].use == UNDECIDED_HUNK) {
+			if (file_diff->hunk[i].use == UNDECIDED_HUNK) {
 				undecided_previous = i;
 				break;
 			}
 
 		undecided_next = -1;
-		for (i = hunk_index + 1; i < s->hunk_nr; i++)
-			if (s->hunk[i].use == UNDECIDED_HUNK) {
+		for (i = hunk_index + 1; i < file_diff->hunk_nr; i++)
+			if (file_diff->hunk[i].use == UNDECIDED_HUNK) {
 				undecided_next = i;
 				break;
 			}
@@ -344,11 +356,12 @@ static int patch_update_file(struct add_p_state *s)
 			strbuf_addstr(&s->buf, ",K");
 		if (undecided_next >= 0)
 			strbuf_addstr(&s->buf, ",j");
-		if (hunk_index + 1 < s->hunk_nr)
+		if (hunk_index + 1 < file_diff->hunk_nr)
 			strbuf_addstr(&s->buf, ",J");
 		color_fprintf(stdout, s->s.prompt_color,
 			      "(%"PRIuMAX"/%"PRIuMAX") ",
-			      (uintmax_t)hunk_index + 1, (uintmax_t)s->hunk_nr);
+			      (uintmax_t)hunk_index + 1,
+			      (uintmax_t)file_diff->hunk_nr);
 		color_fprintf(stdout, s->s.prompt_color,
 			      _("Stage this hunk [y,n,a,d%s,?]? "),
 			      s->buf.buf);
@@ -364,19 +377,19 @@ static int patch_update_file(struct add_p_state *s)
 			hunk->use = USE_HUNK;
 soft_increment:
 			hunk_index = undecided_next < 0 ?
-				s->hunk_nr : undecided_next;
+				file_diff->hunk_nr : undecided_next;
 		} else if (ch == 'n') {
 			hunk->use = SKIP_HUNK;
 			goto soft_increment;
 		} else if (ch == 'a') {
-			for (; hunk_index < s->hunk_nr; hunk_index++) {
-				hunk = s->hunk + hunk_index;
+			for (; hunk_index < file_diff->hunk_nr; hunk_index++) {
+				hunk = file_diff->hunk + hunk_index;
 				if (hunk->use == UNDECIDED_HUNK)
 					hunk->use = USE_HUNK;
 			}
 		} else if (ch == 'd') {
-			for (; hunk_index < s->hunk_nr; hunk_index++) {
-				hunk = s->hunk + hunk_index;
+			for (; hunk_index < file_diff->hunk_nr; hunk_index++) {
+				hunk = file_diff->hunk + hunk_index;
 				if (hunk->use == UNDECIDED_HUNK)
 					hunk->use = SKIP_HUNK;
 			}
@@ -386,7 +399,7 @@ static int patch_update_file(struct add_p_state *s)
 			else
 				err(s, _("No previous hunk"));
 		} else if (s->answer.buf[0] == 'J') {
-			if (hunk_index + 1 < s->hunk_nr)
+			if (hunk_index + 1 < file_diff->hunk_nr)
 				hunk_index++;
 			else
 				err(s, _("No next hunk"));
@@ -406,14 +419,14 @@ static int patch_update_file(struct add_p_state *s)
 	}
 
 	/* Any hunk to be used? */
-	for (i = 0; i < s->hunk_nr; i++)
-		if (s->hunk[i].use == USE_HUNK)
+	for (i = 0; i < file_diff->hunk_nr; i++)
+		if (file_diff->hunk[i].use == USE_HUNK)
 			break;
 
-	if (i < s->hunk_nr) {
+	if (i < file_diff->hunk_nr) {
 		/* At least one hunk selected: apply */
 		strbuf_reset(&s->buf);
-		reassemble_patch(s, &s->buf);
+		reassemble_patch(s, file_diff, &s->buf);
 
 		discard_index(s->s.r->index);
 		setup_child_process(s, &cp, "apply", "--cached", NULL);
@@ -434,6 +447,7 @@ int run_add_p(struct repository *r, const struct pathspec *ps)
 	struct add_p_state s = {
 		{ r }, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT
 	};
+	size_t i;
 
 	init_add_i_state(&s.s, r);
 
@@ -446,8 +460,9 @@ int run_add_p(struct repository *r, const struct pathspec *ps)
 		return -1;
 	}
 
-	if (s.hunk_nr)
-		patch_update_file(&s);
+	for (i = 0; i < s.file_diff_nr; i++)
+		if (patch_update_file(&s, s.file_diff + i))
+			break;
 
 	strbuf_release(&s.answer);
 	strbuf_release(&s.buf);
-- 
gitgitgadget

[PATCH 08/19] built-in add -p: handle deleted empty files

[Johannes Schindelin via GitGitGadget]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

This addresses the same problem as 24ab81ae4d (add-interactive: handle
deletion of empty files, 2009-10-27), although in a different way: we
not only stick the "deleted file" line into its own pseudo hunk, but
also the entire remainder (if any) of the same diff.

That way, we do not have to play any funny games with regards to
coalescing the diff after the user selected what (possibly pseudo-)hunks
to stage.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 add-patch.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/add-patch.c b/add-patch.c
index 7c1b3b3935..c32541f46d 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -33,6 +33,7 @@ struct add_p_state {
 		struct hunk head;
 		struct hunk *hunk;
 		size_t hunk_nr, hunk_alloc;
+		unsigned deleted:1;
 	} *file_diff;
 	size_t file_diff_nr;
 };
@@ -180,6 +181,8 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 	pend = p + plain->len;
 	while (p != pend) {
 		char *eol = memchr(p, '\n', pend - p);
+		const char *deleted = NULL;
+
 		if (!eol)
 			eol = pend;
 
@@ -196,7 +199,11 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 		} else if (p == plain->buf)
 			BUG("diff starts with unexpected line:\n"
 			    "%.*s\n", (int)(eol - p), p);
-		else if (starts_with(p, "@@ ")) {
+		else if (file_diff->deleted)
+			; /* keep the rest of the file in a single "hunk" */
+		else if (starts_with(p, "@@ ") ||
+			 (hunk == &file_diff->head &&
+			  skip_prefix(p, "deleted file", &deleted))) {
 			file_diff->hunk_nr++;
 			ALLOC_GROW(file_diff->hunk, file_diff->hunk_nr,
 				   file_diff->hunk_alloc);
@@ -207,7 +214,9 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 			if (colored)
 				hunk->colored_start = colored_p - colored->buf;
 
-			if (parse_hunk_header(s, hunk) < 0)
+			if (deleted)
+				file_diff->deleted = 1;
+			else if (parse_hunk_header(s, hunk) < 0)
 				return -1;
 		}
 
-- 
gitgitgadget

[PATCH 09/19] built-in app -p: allow selecting a mode change as a "hunk"

[Johannes Schindelin via GitGitGadget]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

This imitates the way the Perl version treats mode changes: it offers
the mode change up for the user to decide, as if it was a diff hunk.

In contrast to the Perl version, we make use of the fact that the mode
line is the first hunk, and explicitly strip out that line from the diff
header if that "hunk" was not selected to be applied, and skipping that
hunk while coalescing the diff. The Perl version plays some kind of diff
line lego instead.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 add-patch.c | 109 +++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 104 insertions(+), 5 deletions(-)

diff --git a/add-patch.c b/add-patch.c
index c32541f46d..2007f55e04 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -33,7 +33,7 @@ struct add_p_state {
 		struct hunk head;
 		struct hunk *hunk;
 		size_t hunk_nr, hunk_alloc;
-		unsigned deleted:1;
+		unsigned deleted:1, mode_change:1;
 	} *file_diff;
 	size_t file_diff_nr;
 };
@@ -129,6 +129,17 @@ static int parse_hunk_header(struct add_p_state *s, struct hunk *hunk)
 	return 0;
 }
 
+static int is_octal(const char *p, size_t len)
+{
+	if (!len)
+		return 0;
+
+	while (len--)
+		if (*p < '0' || *(p++) > '7')
+			return 0;
+	return 1;
+}
+
 static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 {
 	struct argv_array args = ARGV_ARRAY_INIT;
@@ -181,7 +192,7 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 	pend = p + plain->len;
 	while (p != pend) {
 		char *eol = memchr(p, '\n', pend - p);
-		const char *deleted = NULL;
+		const char *deleted = NULL, *mode_change = NULL;
 
 		if (!eol)
 			eol = pend;
@@ -218,8 +229,53 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 				file_diff->deleted = 1;
 			else if (parse_hunk_header(s, hunk) < 0)
 				return -1;
+		} else if (hunk == &file_diff->head &&
+			   skip_prefix(p, "old mode ", &mode_change) &&
+			   is_octal(mode_change, eol - mode_change)) {
+			if (file_diff->mode_change)
+				BUG("double mode change?\n\n%.*s",
+				    (int)(eol - plain->buf), plain->buf);
+			if (file_diff->hunk_nr++)
+				BUG("mode change in the middle?\n\n%.*s",
+				    (int)(eol - plain->buf), plain->buf);
+
+			/*
+			 * Do *not* change `hunk`: the mode change pseudo-hunk
+			 * is _part of_ the header "hunk".
+			 */
+			file_diff->mode_change = 1;
+			ALLOC_GROW(file_diff->hunk, file_diff->hunk_nr,
+				   file_diff->hunk_alloc);
+			memset(file_diff->hunk, 0, sizeof(struct hunk));
+			file_diff->hunk->start = p - plain->buf;
+			if (colored_p)
+				file_diff->hunk->colored_start =
+					colored_p - colored->buf;
+		} else if (hunk == &file_diff->head &&
+			   skip_prefix(p, "new mode ", &mode_change) &&
+			   is_octal(mode_change, eol - mode_change)) {
+
+			/*
+			 * Extend the "mode change" pseudo-hunk to include also
+			 * the "new mode" line.
+			 */
+			if (!file_diff->mode_change)
+				BUG("'new mode' without 'old mode'?\n\n%.*s",
+				    (int)(eol - plain->buf), plain->buf);
+			if (file_diff->hunk_nr != 1)
+				BUG("mode change in the middle?\n\n%.*s",
+				    (int)(eol - plain->buf), plain->buf);
+			if (p - plain->buf != file_diff->hunk->end)
+				BUG("'new mode' does not immediately follow "
+				    "'old mode'?\n\n%.*s",
+				    (int)(eol - plain->buf), plain->buf);
 		}
 
+		if (file_diff->deleted && file_diff->mode_change)
+			BUG("diff contains delete *and* a mode change?!?\n%.*s",
+			    (int)(eol - (plain->buf + file_diff->head.start)),
+			    plain->buf + file_diff->head.start);
+
 		p = eol == pend ? pend : eol + 1;
 		hunk->end = p - plain->buf;
 
@@ -233,6 +289,16 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 
 			hunk->colored_end = colored_p - colored->buf;
 		}
+
+		if (mode_change) {
+			if (file_diff->hunk_nr != 1)
+				BUG("mode change in hunk #%d???",
+				    (int)file_diff->hunk_nr);
+			/* Adjust the end of the "mode change" pseudo-hunk */
+			file_diff->hunk->end = hunk->end;
+			if (colored)
+				file_diff->hunk->colored_end = hunk->colored_end;
+		}
 	}
 
 	return 0;
@@ -284,6 +350,39 @@ static void render_hunk(struct add_p_state *s, struct hunk *hunk,
 			   hunk->end - hunk->start);
 }
 
+static void render_diff_header(struct add_p_state *s,
+			       struct file_diff *file_diff, int colored,
+			       struct strbuf *out)
+{
+	/*
+	 * If there was a mode change, the first hunk is a pseudo hunk that
+	 * corresponds to the mode line in the header. If the user did not want
+	 * to stage that "hunk", we actually have to cut it out from the header.
+	 */
+	int skip_mode_change =
+		file_diff->mode_change && file_diff->hunk->use != USE_HUNK;
+	struct hunk *head = &file_diff->head, *first = file_diff->hunk;
+
+	if (!skip_mode_change) {
+		render_hunk(s, head, 0, colored, out);
+		return;
+	}
+
+	if (colored) {
+		const char *p = s->colored.buf;
+
+		strbuf_add(out, p + head->colored_start,
+			    first->colored_start - head->colored_start);
+		strbuf_add(out, p + first->colored_end,
+			    head->colored_end - first->colored_end);
+	} else {
+		const char *p = s->plain.buf;
+
+		strbuf_add(out, p + head->start, first->start - head->start);
+		strbuf_add(out, p + first->end, head->end - first->end);
+	}
+}
+
 static void reassemble_patch(struct add_p_state *s,
 			     struct file_diff *file_diff, struct strbuf *out)
 {
@@ -291,9 +390,9 @@ static void reassemble_patch(struct add_p_state *s,
 	size_t i;
 	ssize_t delta = 0;
 
-	render_hunk(s, &file_diff->head, 0, 0, out);
+	render_diff_header(s, file_diff, 0, out);
 
-	for (i = 0; i < file_diff->hunk_nr; i++) {
+	for (i = file_diff->mode_change; i < file_diff->hunk_nr; i++) {
 		hunk = file_diff->hunk + i;
 		if (hunk->use != USE_HUNK)
 			delta += hunk->header.old_count
@@ -328,7 +427,7 @@ static int patch_update_file(struct add_p_state *s,
 		return 0;
 
 	strbuf_reset(&s->buf);
-	render_hunk(s, &file_diff->head, 0, colored, &s->buf);
+	render_diff_header(s, file_diff, colored, &s->buf);
 	fputs(s->buf.buf, stdout);
 	for (;;) {
 		if (hunk_index >= file_diff->hunk_nr)
-- 
gitgitgadget

[PATCH 10/19] built-in add -p: show different prompts for mode changes and deletions

[Johannes Schindelin via GitGitGadget]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

Just like the Perl version, we now helpfully ask the user whether they
want to stage a mode change, or a deletion.

Note that we define the prompts in an array, in preparation for a later
patch that changes those prompts to yet different versions for `git
reset -p`, `git stash -p` and `git checkout -p` (which all call the `git
add -p` machinery to do the actual work).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 add-patch.c | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/add-patch.c b/add-patch.c
index 2007f55e04..171025b08d 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -7,6 +7,16 @@
 #include "color.h"
 #include "diff.h"
 
+enum prompt_mode_type {
+	PROMPT_MODE_CHANGE = 0, PROMPT_DELETION, PROMPT_HUNK
+};
+
+static const char *prompt_mode[] = {
+	N_("Stage mode change [y,n,a,d%s,?]? "),
+	N_("Stage deletion [y,n,a,d%s,?]? "),
+	N_("Stage this hunk [y,n,a,d%s,?]? ")
+};
+
 struct hunk_header {
 	unsigned long old_offset, old_count, new_offset, new_count;
 	/*
@@ -422,6 +432,7 @@ static int patch_update_file(struct add_p_state *s,
 	char ch;
 	struct child_process cp = CHILD_PROCESS_INIT;
 	int colored = !!s->colored.len;
+	enum prompt_mode_type prompt_mode_type;
 
 	if (!file_diff->hunk_nr)
 		return 0;
@@ -466,13 +477,20 @@ static int patch_update_file(struct add_p_state *s,
 			strbuf_addstr(&s->buf, ",j");
 		if (hunk_index + 1 < file_diff->hunk_nr)
 			strbuf_addstr(&s->buf, ",J");
+
+		if (file_diff->deleted)
+			prompt_mode_type = PROMPT_DELETION;
+		else if (file_diff->mode_change && !hunk_index)
+			prompt_mode_type = PROMPT_MODE_CHANGE;
+		else
+			prompt_mode_type = PROMPT_HUNK;
+
 		color_fprintf(stdout, s->s.prompt_color,
 			      "(%"PRIuMAX"/%"PRIuMAX") ",
 			      (uintmax_t)hunk_index + 1,
 			      (uintmax_t)file_diff->hunk_nr);
 		color_fprintf(stdout, s->s.prompt_color,
-			      _("Stage this hunk [y,n,a,d%s,?]? "),
-			      s->buf.buf);
+			      _(prompt_mode[prompt_mode_type]), s->buf.buf);
 		fflush(stdout);
 		if (strbuf_getline(&s->answer, stdin) == EOF)
 			break;
-- 
gitgitgadget

[PATCH 11/19] built-in add -p: implement the hunk splitting feature

[Johannes Schindelin via GitGitGadget]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

If this developer's workflow is any indication, then this is *the* most
useful feature of Git's interactive `add `command.

Note: once again, this is not a verbatim conversion from the Perl code
to C: the `hunk_splittable()` function, for example, essentially did all
the work of splitting the hunk, just to find out whether more than one
hunk would have been the result (and then tossed that result into the
trash). In C we instead count the number of resulting hunks (without
actually doing the work of splitting, but just counting the transitions
from non-context lines to context lines), and store that information
with the hunk, and we do that *while* parsing the diff in the first
place.

Another deviation: the built-in `git add -p` was designed with a single
strbuf holding the diff (and another one holding the colored diff, if
that one was asked for) in mind, and hunks essentially store just the
start and end offsets pointing into that strbuf. As a consequence, when
we split hunks, we now use a special mode where the hunk header is
generated dynamically, and only the rest of the hunk is stored using
such start/end offsets. This way, we also avoid the frequent
formatting/re-parsing of the hunk header of the Perl version.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 add-patch.c                | 215 ++++++++++++++++++++++++++++++++++++-
 t/t3701-add-interactive.sh |  12 +++
 2 files changed, 225 insertions(+), 2 deletions(-)

diff --git a/add-patch.c b/add-patch.c
index 171025b08d..2d34ddd7f4 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -28,7 +28,7 @@ struct hunk_header {
 };
 
 struct hunk {
-	size_t start, end, colored_start, colored_end;
+	size_t start, end, colored_start, colored_end, splittable_into;
 	enum { UNDECIDED_HUNK = 0, SKIP_HUNK, USE_HUNK } use;
 	struct hunk_header header;
 };
@@ -155,7 +155,7 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 	struct argv_array args = ARGV_ARRAY_INIT;
 	struct strbuf *plain = &s->plain, *colored = NULL;
 	struct child_process cp = CHILD_PROCESS_INIT;
-	char *p, *pend, *colored_p = NULL, *colored_pend = NULL;
+	char *p, *pend, *colored_p = NULL, *colored_pend = NULL, marker = '\0';
 	size_t file_diff_alloc = 0, i, color_arg_index;
 	struct file_diff *file_diff = NULL;
 	struct hunk *hunk = NULL;
@@ -217,6 +217,7 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 			hunk->start = p - plain->buf;
 			if (colored_p)
 				hunk->colored_start = colored_p - colored->buf;
+			marker = '\0';
 		} else if (p == plain->buf)
 			BUG("diff starts with unexpected line:\n"
 			    "%.*s\n", (int)(eol - p), p);
@@ -225,6 +226,13 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 		else if (starts_with(p, "@@ ") ||
 			 (hunk == &file_diff->head &&
 			  skip_prefix(p, "deleted file", &deleted))) {
+			if (marker == '-' || marker == '+')
+				/*
+				 * Should not happen; previous hunk did not end
+				 * in a context line? Handle it anyway.
+				 */
+				hunk->splittable_into++;
+
 			file_diff->hunk_nr++;
 			ALLOC_GROW(file_diff->hunk, file_diff->hunk_nr,
 				   file_diff->hunk_alloc);
@@ -239,6 +247,12 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 				file_diff->deleted = 1;
 			else if (parse_hunk_header(s, hunk) < 0)
 				return -1;
+
+			/*
+			 * Start counting into how many hunks this one can be
+			 * split
+			 */
+			marker = *p;
 		} else if (hunk == &file_diff->head &&
 			   skip_prefix(p, "old mode ", &mode_change) &&
 			   is_octal(mode_change, eol - mode_change)) {
@@ -286,6 +300,11 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 			    (int)(eol - (plain->buf + file_diff->head.start)),
 			    plain->buf + file_diff->head.start);
 
+		if ((marker == '-' || marker == '+') && *p == ' ')
+			hunk->splittable_into++;
+		if (marker && *p != '\\')
+			marker = *p;
+
 		p = eol == pend ? pend : eol + 1;
 		hunk->end = p - plain->buf;
 
@@ -311,9 +330,30 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 		}
 	}
 
+	if (marker == '-' || marker == '+')
+		/*
+		 * Last hunk ended in non-context line (i.e. it appended lines
+		 * to the file, so there are no trailing context lines).
+		 */
+		hunk->splittable_into++;
+
 	return 0;
 }
 
+static size_t find_next_line(struct strbuf *sb, size_t offset)
+{
+	char *eol;
+
+	if (offset >= sb->len)
+		BUG("looking for next line beyond buffer (%d >= %d)\n%s",
+		    (int)offset, (int)sb->len, sb->buf);
+
+	eol = memchr(sb->buf + offset, '\n', sb->len - offset);
+	if (!eol)
+		return sb->len;
+	return eol - sb->buf + 1;
+}
+
 static void render_hunk(struct add_p_state *s, struct hunk *hunk,
 			ssize_t delta, int colored, struct strbuf *out)
 {
@@ -412,6 +452,165 @@ static void reassemble_patch(struct add_p_state *s,
 	}
 }
 
+static int split_hunk(struct add_p_state *s, struct file_diff *file_diff,
+		       size_t hunk_index)
+{
+	int colored = !!s->colored.len, first = 1;
+	struct hunk *hunk = file_diff->hunk + hunk_index;
+	size_t splittable_into;
+	size_t end, colored_end, current, colored_current = 0, context_line_count;
+	struct hunk_header remaining, *header;
+	char marker, ch;
+
+	if (hunk_index >= file_diff->hunk_nr)
+		BUG("invalid hunk index: %d (must be >= 0 and < %d)",
+		    (int)hunk_index, (int)file_diff->hunk_nr);
+
+	if (hunk->splittable_into < 2)
+		return 0;
+	splittable_into = hunk->splittable_into;
+
+	end = hunk->end;
+	colored_end = hunk->colored_end;
+
+	remaining = hunk->header;
+
+	file_diff->hunk_nr += splittable_into - 1;
+	ALLOC_GROW(file_diff->hunk, file_diff->hunk_nr, file_diff->hunk_alloc);
+	if (hunk_index + splittable_into < file_diff->hunk_nr)
+		memmove(file_diff->hunk + hunk_index + splittable_into,
+			file_diff->hunk + hunk_index + 1,
+			(file_diff->hunk_nr - hunk_index - splittable_into)
+			* sizeof(*hunk));
+	hunk = file_diff->hunk + hunk_index;
+	hunk->splittable_into = 1;
+	memset(hunk + 1, 0, (splittable_into - 1) * sizeof(*hunk));
+
+	header = &hunk->header;
+	header->old_count = header->new_count = 0;
+
+	current = hunk->start;
+	if (colored)
+		colored_current = hunk->colored_start;
+	marker = '\0';
+	context_line_count = 0;
+
+	while (splittable_into > 1) {
+		ch = s->plain.buf[current];
+
+		if (!ch)
+			BUG("buffer overrun while splitting hunks");
+
+		/*
+		 * Is this the first context line after a chain of +/- lines?
+		 * Then record the start of the next split hunk.
+		 */
+		if ((marker == '-' || marker == '+') && ch == ' ') {
+			first = 0;
+			hunk[1].start = current;
+			if (colored)
+				hunk[1].colored_start = colored_current;
+			context_line_count = 0;
+		}
+
+		/*
+		 * Was the previous line a +/- one? Alternatively, is this the
+		 * first line (and not a +/- one)?
+		 *
+		 * Then just increment the appropriate counter and continue
+		 * with the next line.
+		 */
+		if (marker != ' ' || (ch != '-' && ch != '+')) {
+next_hunk_line:
+			/* Comment lines are attached to the previous line */
+			if (ch == '\\')
+				ch = marker ? marker : ' ';
+
+			/* current hunk not done yet */
+			if (ch == ' ')
+				context_line_count++;
+			else if (ch == '-')
+				header->old_count++;
+			else if (ch == '+')
+				header->new_count++;
+			else
+				BUG("unhandled diff marker: '%c'", ch);
+			marker = ch;
+			current = find_next_line(&s->plain, current);
+			if (colored)
+				colored_current =
+					find_next_line(&s->colored,
+						       colored_current);
+			continue;
+		}
+
+		/*
+		 * We got us the start of a new hunk!
+		 *
+		 * This is a context line, so it is shared with the previous
+		 * hunk, if any.
+		 */
+
+		if (first) {
+			if (header->old_count || header->new_count)
+				BUG("counts are off: %d/%d",
+				    (int)header->old_count,
+				    (int)header->new_count);
+
+			header->old_count = context_line_count;
+			header->new_count = context_line_count;
+			context_line_count = 0;
+			first = 0;
+			goto next_hunk_line;
+		}
+
+		remaining.old_offset += header->old_count;
+		remaining.old_count -= header->old_count;
+		remaining.new_offset += header->new_count;
+		remaining.new_count -= header->new_count;
+
+		/* initialize next hunk header's offsets */
+		hunk[1].header.old_offset =
+			header->old_offset + header->old_count;
+		hunk[1].header.new_offset =
+			header->new_offset + header->new_count;
+
+		/* add one split hunk */
+		header->old_count += context_line_count;
+		header->new_count += context_line_count;
+
+		hunk->end = current;
+		if (colored)
+			hunk->colored_end = colored_current;
+
+		hunk++;
+		hunk->splittable_into = 1;
+		hunk->use = hunk[-1].use;
+		header = &hunk->header;
+
+		header->old_count = header->new_count = context_line_count;
+		context_line_count = 0;
+
+		splittable_into--;
+		marker = ch;
+	}
+
+	/* last hunk simply gets the rest */
+	if (header->old_offset != remaining.old_offset)
+		BUG("miscounted old_offset: %lu != %lu",
+		    header->old_offset, remaining.old_offset);
+	if (header->new_offset != remaining.new_offset)
+		BUG("miscounted new_offset: %lu != %lu",
+		    header->new_offset, remaining.new_offset);
+	header->old_count = remaining.old_count;
+	header->new_count = remaining.new_count;
+	hunk->end = end;
+	if (colored)
+		hunk->colored_end = colored_end;
+
+	return 0;
+}
+
 static const char help_patch_text[] =
 N_("y - stage this hunk\n"
    "n - do not stage this hunk\n"
@@ -421,6 +620,7 @@ N_("y - stage this hunk\n"
    "J - leave this hunk undecided, see next hunk\n"
    "k - leave this hunk undecided, see previous undecided hunk\n"
    "K - leave this hunk undecided, see previous hunk\n"
+   "s - split the current hunk into smaller hunks\n"
    "? - print help\n");
 
 static int patch_update_file(struct add_p_state *s,
@@ -477,6 +677,8 @@ static int patch_update_file(struct add_p_state *s,
 			strbuf_addstr(&s->buf, ",j");
 		if (hunk_index + 1 < file_diff->hunk_nr)
 			strbuf_addstr(&s->buf, ",J");
+		if (hunk->splittable_into > 1)
+			strbuf_addstr(&s->buf, ",s");
 
 		if (file_diff->deleted)
 			prompt_mode_type = PROMPT_DELETION;
@@ -539,6 +741,15 @@ static int patch_update_file(struct add_p_state *s,
 				hunk_index = undecided_next;
 			else
 				err(s, _("No next hunk"));
+		} else if (s->answer.buf[0] == 's') {
+			size_t splittable_into = hunk->splittable_into;
+			if (splittable_into < 2)
+				err(s, _("Sorry, cannot split this hunk"));
+			else if (!split_hunk(s, file_diff,
+					     hunk - file_diff->hunk))
+				color_fprintf_ln(stdout, s->s.header_color,
+						 _("Split into %d hunks."),
+						 (int)splittable_into);
 		} else
 			color_fprintf(stdout, s->s.help_color,
 				      _(help_patch_text));
diff --git a/t/t3701-add-interactive.sh b/t/t3701-add-interactive.sh
index 5db6432e33..fe383be50e 100755
--- a/t/t3701-add-interactive.sh
+++ b/t/t3701-add-interactive.sh
@@ -442,6 +442,18 @@ test_expect_failure 'split hunk "add -p (no, yes, edit)"' '
 	! grep "^+31" actual
 '
 
+test_expect_success 'split hunk with incomplete line at end' '
+	git reset --hard &&
+	printf "missing LF" >>test &&
+	git add test &&
+	test_write_lines before 10 20 30 40 50 60 70 >test &&
+	git grep --cached missing &&
+	test_write_lines s n y q | git add -p &&
+	test_must_fail git grep --cached missing &&
+	git grep before &&
+	test_must_fail git grep --cached before
+'
+
 test_expect_failure 'edit, adding lines to the first hunk' '
 	test_write_lines 10 11 20 30 40 50 51 60 >test &&
 	git reset &&
-- 
gitgitgadget

[PATCH 12/19] built-in add -p: coalesce hunks after splitting them

[Johannes Schindelin via GitGitGadget]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

This is considered "the right thing to do", according to 933e44d3a0
("add -p": work-around an old laziness that does not coalesce hunks,
2011-04-06).

Note: we cannot simply modify the hunks while merging them; Once we
implement hunk editing, we will call `reassemble_patch()` whenever a
hunk is edited, therefore we must not modify the hunks (because the user
might e.g. hit `K` and change their mind whether to stage the previous
hunk).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 add-patch.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 57 insertions(+), 1 deletion(-)

diff --git a/add-patch.c b/add-patch.c
index 2d34ddd7f4..c8d84aec68 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -433,6 +433,55 @@ static void render_diff_header(struct add_p_state *s,
 	}
 }
 
+/* Coalesce hunks again that were split */
+static int merge_hunks(struct add_p_state *s, struct file_diff *file_diff,
+		       size_t *hunk_index, struct hunk *merged)
+{
+	size_t i = *hunk_index;
+	struct hunk *hunk = file_diff->hunk + i;
+	/* `header` corresponds to the merged hunk */
+	struct hunk_header *header = &merged->header, *next;
+
+	if (hunk->use != USE_HUNK)
+		return 0;
+
+	*merged = *hunk;
+	/* We simply skip the colored part (if any) when merging hunks */
+	merged->colored_start = merged->colored_end = 0;
+
+	for (; i + 1 < file_diff->hunk_nr; i++) {
+		hunk++;
+		next = &hunk->header;
+
+		/*
+		 * Stop merging hunks when:
+		 *
+		 * - the hunk is not selected for use, or
+		 * - the hunk does not overlap with the already-merged hunk(s)
+		 */
+		if (hunk->use != USE_HUNK ||
+		    header->new_offset >= next->new_offset ||
+		    header->new_offset + header->new_count < next->new_offset ||
+		    merged->start >= hunk->start ||
+		    merged->end < hunk->start)
+			break;
+
+		merged->end = hunk->end;
+		merged->colored_end = hunk->colored_end;
+
+		header->old_count = next->old_offset + next->old_count
+			- header->old_offset;
+		header->new_count = next->new_offset + next->new_count
+			- header->new_offset;
+	}
+
+	if (i == *hunk_index)
+		return 0;
+
+	*hunk_index = i;
+	return 1;
+}
+
 static void reassemble_patch(struct add_p_state *s,
 			     struct file_diff *file_diff, struct strbuf *out)
 {
@@ -443,12 +492,19 @@ static void reassemble_patch(struct add_p_state *s,
 	render_diff_header(s, file_diff, 0, out);
 
 	for (i = file_diff->mode_change; i < file_diff->hunk_nr; i++) {
+		struct hunk merged = { 0 };
+
 		hunk = file_diff->hunk + i;
 		if (hunk->use != USE_HUNK)
 			delta += hunk->header.old_count
 				- hunk->header.new_count;
-		else
+		else {
+			/* merge overlapping hunks into a temporary hunk */
+			if (merge_hunks(s, file_diff, &i, &merged))
+				hunk = &merged;
+
 			render_hunk(s, hunk, delta, 0, out);
+		}
 	}
 }
 
-- 
gitgitgadget

[PATCH 13/19] strbuf: add a helper function to call the editor "on an strbuf"

[Johannes Schindelin via GitGitGadget]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

This helper supports the scenario where Git has a populated `strbuf` and
wants to let the user edit it interactively.

In `git add -p`, we will use this to allow interactive hunk editing: the
diff hunks are already in memory, but we need to write them out to a
file so that an editor can be launched, then read everything back once
the user is done editing.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 strbuf.c | 28 ++++++++++++++++++++++++++++
 strbuf.h | 11 +++++++++++
 2 files changed, 39 insertions(+)

diff --git a/strbuf.c b/strbuf.c
index aa48d179a9..f19da55b07 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -1125,3 +1125,31 @@ int strbuf_normalize_path(struct strbuf *src)
 	strbuf_release(&dst);
 	return 0;
 }
+
+int strbuf_edit_interactively(struct strbuf *buffer, const char *path,
+			      const char *const *env)
+{
+	char *path2 = NULL;
+	int fd, res = 0;
+
+	if (!is_absolute_path(path))
+		path = path2 = xstrdup(git_path("%s", path));
+
+	fd = open(path, O_WRONLY | O_CREAT | O_TRUNC, 0666);
+	if (fd < 0)
+		res = error_errno(_("could not open '%s' for writing"), path);
+	else if (write_in_full(fd, buffer->buf, buffer->len) < 0) {
+		res = error_errno(_("could not write to '%s'"), path);
+		close(fd);
+	} else if (close(fd) < 0)
+		res = error_errno(_("could not close '%s'"), path);
+	else {
+		strbuf_reset(buffer);
+		if (launch_editor(path, buffer, env) < 0)
+			res = error_errno(_("could not edit '%s'"), path);
+		unlink(path);
+	}
+
+	free(path2);
+	return res;
+}
diff --git a/strbuf.h b/strbuf.h
index 84cf969721..bfa66569a4 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -621,6 +621,17 @@ int launch_editor(const char *path, struct strbuf *buffer,
 int launch_sequence_editor(const char *path, struct strbuf *buffer,
 			   const char *const *env);
 
+/*
+ * In contrast to `launch_editor()`, this function writes out the contents
+ * of the specified file first, then clears the `buffer`, then launches
+ * the editor and reads back in the file contents into the `buffer`.
+ * Finally, it deletes the temporary file.
+ *
+ * If `path` is relative, it refers to a file in the `.git` directory.
+ */
+int strbuf_edit_interactively(struct strbuf *buffer, const char *path,
+			      const char *const *env);
+
 void strbuf_add_lines(struct strbuf *sb,
 		      const char *prefix,
 		      const char *buf,
-- 
gitgitgadget

[PATCH 14/19] built-in add -p: implement hunk editing

[Johannes Schindelin via GitGitGadget]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

Just like `git add --edit` allows the user to edit the diff before it is
being applied to the index, this feature allows the user to edit the
diff *hunk*.

Naturally, it gets a bit more complicated here because the result has
to play well with the remaining hunks of the overall diff. Therefore,
we have to do a loop in which we let the user edit the hunk, then test
whether the result would work, and if not, drop the edits and let the
user decide whether to try editing the hunk again.

Note: in contrast to the Perl version, we use the same diff
"coalescing" (i.e. merging overlapping hunks into a single one) also for
the check after editing, and we introduce a new flag for that purpose
that asks the `reassemble_patch()` function to pretend that all hunks
were selected for use.

This allows us to continue to run `git apply` *without* the
`--allow-overlap` option (unlike the Perl version), and it also fixes
two known breakages in `t3701-add-interactive.sh` (which we cannot mark
as resolved so far because the Perl script version is still the default
and continues to have those breakages).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 add-interactive.c |   6 +
 add-interactive.h |   3 +
 add-patch.c       | 333 +++++++++++++++++++++++++++++++++++++++++++---
 3 files changed, 325 insertions(+), 17 deletions(-)

diff --git a/add-interactive.c b/add-interactive.c
index 29356c5aa2..6a5048c83e 100644
--- a/add-interactive.c
+++ b/add-interactive.c
@@ -46,6 +46,12 @@ void init_add_i_state(struct add_i_state *s, struct repository *r)
 	init_color(r, s, "reset", s->reset_color, GIT_COLOR_RESET);
 	init_color(r, s, "fraginfo", s->fraginfo_color,
 		   diff_get_color(s->use_color, DIFF_FRAGINFO));
+	init_color(r, s, "context", s->context_color,
+		diff_get_color(s->use_color, DIFF_CONTEXT));
+	init_color(r, s, "old", s->file_old_color,
+		diff_get_color(s->use_color, DIFF_FILE_OLD));
+	init_color(r, s, "new", s->file_new_color,
+		diff_get_color(s->use_color, DIFF_FILE_NEW));
 }
 
 /*
diff --git a/add-interactive.h b/add-interactive.h
index 584f304a9a..062dc3646c 100644
--- a/add-interactive.h
+++ b/add-interactive.h
@@ -12,6 +12,9 @@ struct add_i_state {
 	char error_color[COLOR_MAXLEN];
 	char reset_color[COLOR_MAXLEN];
 	char fraginfo_color[COLOR_MAXLEN];
+	char context_color[COLOR_MAXLEN];
+	char file_old_color[COLOR_MAXLEN];
+	char file_new_color[COLOR_MAXLEN];
 };
 
 void init_add_i_state(struct add_i_state *s, struct repository *r);
diff --git a/add-patch.c b/add-patch.c
index c8d84aec68..ea863ca09d 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -29,6 +29,7 @@ struct hunk_header {
 
 struct hunk {
 	size_t start, end, colored_start, colored_end, splittable_into;
+	ssize_t delta;
 	enum { UNDECIDED_HUNK = 0, SKIP_HUNK, USE_HUNK } use;
 	struct hunk_header header;
 };
@@ -435,14 +436,14 @@ static void render_diff_header(struct add_p_state *s,
 
 /* Coalesce hunks again that were split */
 static int merge_hunks(struct add_p_state *s, struct file_diff *file_diff,
-		       size_t *hunk_index, struct hunk *merged)
+		       size_t *hunk_index, int use_all, struct hunk *merged)
 {
-	size_t i = *hunk_index;
+	size_t i = *hunk_index, delta;
 	struct hunk *hunk = file_diff->hunk + i;
 	/* `header` corresponds to the merged hunk */
 	struct hunk_header *header = &merged->header, *next;
 
-	if (hunk->use != USE_HUNK)
+	if (!use_all && hunk->use != USE_HUNK)
 		return 0;
 
 	*merged = *hunk;
@@ -459,20 +460,99 @@ static int merge_hunks(struct add_p_state *s, struct file_diff *file_diff,
 		 * - the hunk is not selected for use, or
 		 * - the hunk does not overlap with the already-merged hunk(s)
 		 */
-		if (hunk->use != USE_HUNK ||
-		    header->new_offset >= next->new_offset ||
-		    header->new_offset + header->new_count < next->new_offset ||
-		    merged->start >= hunk->start ||
-		    merged->end < hunk->start)
+		if ((!use_all && hunk->use != USE_HUNK) ||
+		    header->new_offset >= next->new_offset + merged->delta ||
+		    header->new_offset + header->new_count
+		    < next->new_offset + merged->delta)
 			break;
 
-		merged->end = hunk->end;
-		merged->colored_end = hunk->colored_end;
+		/*
+		 * If the hunks were not edited, and overlap, we can simply
+		 * extend the line range.
+		 */
+		if (merged->start < hunk->start && merged->end > hunk->start) {
+			merged->end = hunk->end;
+			merged->colored_end = hunk->colored_end;
+			delta = 0;
+		} else {
+			const char *plain = s->plain.buf;
+			size_t  overlapping_line_count = header->new_offset
+				+ header->new_count - merged->delta
+				- next->new_offset;
+			size_t overlap_end = hunk->start;
+			size_t overlap_start = overlap_end;
+			size_t overlap_next, len, j;
+
+			/*
+			 * One of the hunks was edited: the modified hunk was
+			 * appended to the strbuf `s->plain`.
+			 *
+			 * Let's ensure that at least the last context line of
+			 * the first hunk overlaps with the corresponding line
+			 * of the second hunk, and then merge.
+			 */
+			for (j = 0; j < overlapping_line_count; j++) {
+				overlap_next = find_next_line(&s->plain,
+							      overlap_end);
+
+				if (overlap_next > hunk->end)
+					BUG("failed to find %d context lines "
+					    "in:\n%.*s",
+					    (int)overlapping_line_count,
+					    (int)(hunk->end - hunk->start),
+					    plain + hunk->start);
+
+				if (plain[overlap_end] != ' ')
+					return error(_("expected context line "
+						       "#%d in\n%.*s"),
+						     (int)(j + 1),
+						     (int)(hunk->end
+							   - hunk->start),
+						     plain + hunk->start);
+
+				overlap_start = overlap_end;
+				overlap_end = overlap_next;
+			}
+			len = overlap_end - overlap_start;
+
+			if (len > merged->end - merged->start ||
+			    memcmp(plain + merged->end - len,
+				   plain + overlap_start, len))
+				return error(_("hunks do not overlap:\n%.*s\n"
+					       "\tdoes not end with:\n%.*s"),
+					     (int)(merged->end - merged->start),
+					     plain + merged->start,
+					     (int)len, plain + overlap_start);
+
+			/*
+			 * Since the start-end ranges are not adjacent, we
+			 * cannot simply take the union of the ranges. To
+			 * address that, we temporarily append the union of the
+			 * lines to the `plain` strbuf.
+			 */
+			if (merged->end != s->plain.len) {
+				size_t start = s->plain.len;
+
+				strbuf_add(&s->plain, plain + merged->start,
+					   merged->end - merged->start);
+				plain = s->plain.buf;
+				merged->start = start;
+				merged->end = s->plain.len;
+			}
+
+			strbuf_add(&s->plain,
+				   plain + overlap_end,
+				   hunk->end - overlap_end);
+			merged->end = s->plain.len;
+			merged->splittable_into += hunk->splittable_into;
+			delta = merged->delta;
+			merged->delta += hunk->delta;
+		}
 
 		header->old_count = next->old_offset + next->old_count
 			- header->old_offset;
-		header->new_count = next->new_offset + next->new_count
-			- header->new_offset;
+		header->new_count = next->new_offset + delta
+			+ next->new_count - header->new_offset;
 	}
 
 	if (i == *hunk_index)
@@ -483,10 +563,11 @@ static int merge_hunks(struct add_p_state *s, struct file_diff *file_diff,
 }
 
 static void reassemble_patch(struct add_p_state *s,
-			     struct file_diff *file_diff, struct strbuf *out)
+			     struct file_diff *file_diff, int use_all,
+			     struct strbuf *out)
 {
 	struct hunk *hunk;
-	size_t i;
+	size_t save_len = s->plain.len, i;
 	ssize_t delta = 0;
 
 	render_diff_header(s, file_diff, 0, out);
@@ -495,15 +576,24 @@ static void reassemble_patch(struct add_p_state *s,
 		struct hunk merged = { 0 };
 
 		hunk = file_diff->hunk + i;
-		if (hunk->use != USE_HUNK)
+		if (!use_all && hunk->use != USE_HUNK)
 			delta += hunk->header.old_count
 				- hunk->header.new_count;
 		else {
 			/* merge overlapping hunks into a temporary hunk */
-			if (merge_hunks(s, file_diff, &i, &merged))
+			if (merge_hunks(s, file_diff, &i, use_all, &merged))
 				hunk = &merged;
 
 			render_hunk(s, hunk, delta, 0, out);
+
+			/*
+			 * In case `merge_hunks()` used `plain` as a scratch
+			 * pad (this happens when an edited hunk had to be
+			 * coalesced with another hunk).
+			 */
+			strbuf_setlen(&s->plain, save_len);
+
+			delta += hunk->delta;
 		}
 	}
 }
@@ -667,6 +757,204 @@ static int split_hunk(struct add_p_state *s, struct file_diff *file_diff,
 	return 0;
 }
 
+static void recolor_hunk(struct add_p_state *s, struct hunk *hunk)
+{
+	const char *plain = s->plain.buf;
+	size_t current, eol, next;
+
+	if (!s->colored.len)
+		return;
+
+	hunk->colored_start = s->colored.len;
+	for (current = hunk->start; current < hunk->end; ) {
+		for (eol = current; eol < hunk->end; eol++)
+			if (plain[eol] == '\n')
+				break;
+		next = eol + (eol < hunk->end);
+		if (eol > current && plain[eol - 1] == '\r')
+			eol--;
+
+		strbuf_addstr(&s->colored,
+			      plain[current] == '-' ?
+			      s->s.file_old_color :
+			      plain[current] == '+' ?
+			      s->s.file_new_color :
+			      s->s.context_color);
+		strbuf_add(&s->colored, plain + current, eol - current);
+		strbuf_addstr(&s->colored, GIT_COLOR_RESET);
+		if (next > eol)
+			strbuf_add(&s->colored, plain + eol, next - eol);
+		current = next;
+	}
+	hunk->colored_end = s->colored.len;
+}
+
+static int edit_hunk_manually(struct add_p_state *s, struct hunk *hunk)
+{
+	size_t i;
+
+	strbuf_reset(&s->buf);
+	strbuf_commented_addf(&s->buf, _("Manual hunk edit mode -- see bottom for "
+				      "a quick guide.\n"));
+	render_hunk(s, hunk, 0, 0, &s->buf);
+	strbuf_commented_addf(&s->buf,
+			      _("---\n"
+				"To remove '%c' lines, make them ' ' lines "
+				"(context).\n"
+				"To remove '%c' lines, delete them.\n"
+				"Lines starting with %c will be removed.\n"),
+			      '-', '+', comment_line_char);
+	strbuf_commented_addf(&s->buf,
+			      _("If the patch applies cleanly, the edited hunk "
+				"will immediately be\n"
+				"marked for staging.\n"));
+	/*
+	 * TRANSLATORS: 'it' refers to the patch mentioned in the previous
+	 * messages.
+	 */
+	strbuf_commented_addf(&s->buf,
+			      _("If it does not apply cleanly, you will be "
+				"given an opportunity to\n"
+				"edit again.  If all lines of the hunk are "
+				"removed, then the edit is\n"
+				"aborted and the hunk is left unchanged.\n"));
+
+	if (strbuf_edit_interactively(&s->buf, "addp-hunk-edit.diff", NULL) < 0)
+		return -1;
+
+	/* strip out commented lines */
+	hunk->start = s->plain.len;
+	for (i = 0; i < s->buf.len; ) {
+		size_t next = find_next_line(&s->buf, i);
+
+		if (s->buf.buf[i] != comment_line_char)
+			strbuf_add(&s->plain, s->buf.buf + i, next - i);
+		i = next;
+	}
+
+	hunk->end = s->plain.len;
+	if (hunk->end == hunk->start)
+		/* The user aborted editing by deleting everything */
+		return 0;
+
+	recolor_hunk(s, hunk);
+
+	/*
+	 * If the hunk header is intact, parse it, otherwise simply use the
+	 * hunk header prior to editing (which will adjust `hunk->start` to
+	 * skip the hunk header).
+	 */
+	if (s->plain.buf[hunk->start] == '@' &&
+	    parse_hunk_header(s, hunk) < 0)
+		return error(_("could not parse hunk header"));
+
+	return 1;
+}
+
+static ssize_t recount_edited_hunk(struct add_p_state *s, struct hunk *hunk,
+				   size_t orig_old_count, size_t orig_new_count)
+{
+	struct hunk_header *header = &hunk->header;
+	size_t i;
+
+	header->old_count = header->new_count = 0;
+	for (i = hunk->start; i < hunk->end; ) {
+		switch (s->plain.buf[i]) {
+		case '-':
+			header->old_count++;
+			break;
+		case '+':
+			header->new_count++;
+			break;
+		case ' ': case '\r': case '\n':
+			header->old_count++;
+			header->new_count++;
+			break;
+		}
+
+		i = find_next_line(&s->plain, i);
+	}
+
+	return orig_old_count - orig_new_count
+		- header->old_count + header->new_count;
+}
+
+static int run_apply_check(struct add_p_state *s,
+			   struct file_diff *file_diff)
+{
+	struct child_process cp = CHILD_PROCESS_INIT;
+
+	strbuf_reset(&s->buf);
+	reassemble_patch(s, file_diff, 1, &s->buf);
+
+	setup_child_process(s, &cp,
+			    "apply", "--cached", "--check", NULL);
+	if (pipe_command(&cp, s->buf.buf, s->buf.len, NULL, 0, NULL, 0))
+		return error(_("'git apply --cached' failed"));
+
+	return 0;
+}
+
+static int prompt_yesno(struct add_p_state *s, const char *prompt)
+{
+	for (;;) {
+		color_fprintf(stdout, s->s.prompt_color, "%s", _(prompt));
+		fflush(stdout);
+		if (strbuf_getline(&s->answer, stdin) == EOF)
+			return -1;
+		strbuf_trim_trailing_newline(&s->answer);
+		switch (tolower(s->answer.buf[0])) {
+		case 'n': return 0;
+		case 'y': return 1;
+		}
+	}
+}
+
+static int edit_hunk_loop(struct add_p_state *s,
+			  struct file_diff *file_diff, struct hunk *hunk)
+{
+	size_t plain_len = s->plain.len, colored_len = s->colored.len;
+	struct hunk backup;
+
+	backup = *hunk;
+
+	for (;;) {
+		int res = edit_hunk_manually(s, hunk);
+		if (res == 0) {
+			/* abandonded */
+			*hunk = backup;
+			return -1;
+		}
+
+		if (res > 0) {
+			hunk->delta +=
+				recount_edited_hunk(s, hunk,
+						    backup.header.old_count,
+						    backup.header.new_count);
+			if (!run_apply_check(s, file_diff))
+				return 0;
+		}
+
+		/* Drop edits (they were appended to s->plain) */
+		strbuf_setlen(&s->plain, plain_len);
+		strbuf_setlen(&s->colored, colored_len);
+		*hunk = backup;
+
+		/*
+		 * TRANSLATORS: do not translate [y/n]
+		 * The program will only accept that input at this point.
+		 * Consider translating (saying "no" discards!) as
+		 * (saying "n" for "no" discards!) if the translation
+		 * of the word "no" does not start with n.
+		 */
+		res = prompt_yesno(s, _("Your edited hunk does not apply. "
+					"Edit again (saying \"no\" discards!) "
+					"[y/n]? "));
+		if (res < 1)
+			return -1;
+	}
+}
+
 static const char help_patch_text[] =
 N_("y - stage this hunk\n"
    "n - do not stage this hunk\n"
@@ -677,6 +965,7 @@ N_("y - stage this hunk\n"
    "k - leave this hunk undecided, see previous undecided hunk\n"
    "K - leave this hunk undecided, see previous hunk\n"
    "s - split the current hunk into smaller hunks\n"
+   "e - manually edit the current hunk\n"
    "? - print help\n");
 
 static int patch_update_file(struct add_p_state *s,
@@ -735,6 +1024,9 @@ static int patch_update_file(struct add_p_state *s,
 			strbuf_addstr(&s->buf, ",J");
 		if (hunk->splittable_into > 1)
 			strbuf_addstr(&s->buf, ",s");
+		if (hunk_index + 1 > file_diff->mode_change &&
+		    !file_diff->deleted)
+			strbuf_addstr(&s->buf, ",e");
 
 		if (file_diff->deleted)
 			prompt_mode_type = PROMPT_DELETION;
@@ -806,6 +1098,13 @@ static int patch_update_file(struct add_p_state *s,
 				color_fprintf_ln(stdout, s->s.header_color,
 						 _("Split into %d hunks."),
 						 (int)splittable_into);
+		} else if (s->answer.buf[0] == 'e') {
+			if (hunk_index + 1 == file_diff->mode_change)
+				err(s, _("Sorry, cannot edit this hunk"));
+			else if (edit_hunk_loop(s, file_diff, hunk) >= 0) {
+				hunk->use = USE_HUNK;
+				goto soft_increment;
+			}
 		} else
 			color_fprintf(stdout, s->s.help_color,
 				      _(help_patch_text));
@@ -819,7 +1118,7 @@ static int patch_update_file(struct add_p_state *s,
 	if (i < file_diff->hunk_nr) {
 		/* At least one hunk selected: apply */
 		strbuf_reset(&s->buf);
-		reassemble_patch(s, file_diff, &s->buf);
+		reassemble_patch(s, file_diff, 0, &s->buf);
 
 		discard_index(s->s.r->index);
 		setup_child_process(s, &cp, "apply", "--cached", NULL);
-- 
gitgitgadget

[PATCH 15/19] built-in add -p: implement the 'g' ("goto") command

[Johannes Schindelin via GitGitGadget]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

With this patch, it is now possible to see a summary of the available
hunks and to navigate between them (by number).

A test is added to verify that this behavior matches the one of the Perl
version of `git add -p`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 add-patch.c                | 88 ++++++++++++++++++++++++++++++++++++++
 t/t3701-add-interactive.sh | 16 +++++++
 2 files changed, 104 insertions(+)

diff --git a/add-patch.c b/add-patch.c
index ea863ca09d..fdbb1e3e22 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -955,6 +955,54 @@ static int edit_hunk_loop(struct add_p_state *s,
 	}
 }
 
+#define SUMMARY_HEADER_WIDTH 20
+#define SUMMARY_LINE_WIDTH 80
+static void summarize_hunk(struct add_p_state *s, struct hunk *hunk,
+			   struct strbuf *out)
+{
+	struct hunk_header *header = &hunk->header;
+	struct strbuf *plain = &s->plain;
+	size_t len = out->len, i;
+
+	strbuf_addf(out, " -%lu,%lu +%lu,%lu ",
+		    header->old_offset, header->old_count,
+		    header->new_offset, header->new_count);
+	if (out->len - len < SUMMARY_HEADER_WIDTH)
+		strbuf_addchars(out, ' ',
+				SUMMARY_HEADER_WIDTH + len - out->len);
+	for (i = hunk->start; i < hunk->end; i = find_next_line(plain, i))
+		if (plain->buf[i] != ' ')
+			break;
+	if (i < hunk->end)
+		strbuf_add(out, plain->buf + i, find_next_line(plain, i) - i);
+	if (out->len - len > SUMMARY_LINE_WIDTH)
+		strbuf_setlen(out, len + SUMMARY_LINE_WIDTH);
+	strbuf_complete_line(out);
+}
+
+#define DISPLAY_HUNKS_LINES 20
+static size_t display_hunks(struct add_p_state *s,
+			    struct file_diff *file_diff, size_t start_index)
+{
+	size_t end_index = start_index + DISPLAY_HUNKS_LINES;
+
+	if (end_index > file_diff->hunk_nr)
+		end_index = file_diff->hunk_nr;
+
+	while (start_index < end_index) {
+		struct hunk *hunk = file_diff->hunk + start_index++;
+
+		strbuf_reset(&s->buf);
+		strbuf_addf(&s->buf, "%c%2d: ", hunk->use == USE_HUNK ? '+'
+			    : hunk->use == SKIP_HUNK ? '-' : ' ',
+			    (int)start_index);
+		summarize_hunk(s, hunk, &s->buf);
+		fputs(s->buf.buf, stdout);
+	}
+
+	return end_index;
+}
+
 static const char help_patch_text[] =
 N_("y - stage this hunk\n"
    "n - do not stage this hunk\n"
@@ -964,6 +1012,7 @@ N_("y - stage this hunk\n"
    "J - leave this hunk undecided, see next hunk\n"
    "k - leave this hunk undecided, see previous undecided hunk\n"
    "K - leave this hunk undecided, see previous hunk\n"
+   "g - select a hunk to go to\n"
    "s - split the current hunk into smaller hunks\n"
    "e - manually edit the current hunk\n"
    "? - print help\n");
@@ -1022,6 +1071,8 @@ static int patch_update_file(struct add_p_state *s,
 			strbuf_addstr(&s->buf, ",j");
 		if (hunk_index + 1 < file_diff->hunk_nr)
 			strbuf_addstr(&s->buf, ",J");
+		if (file_diff->hunk_nr > 1)
+			strbuf_addstr(&s->buf, ",g");
 		if (hunk->splittable_into > 1)
 			strbuf_addstr(&s->buf, ",s");
 		if (hunk_index + 1 > file_diff->mode_change &&
@@ -1089,6 +1140,43 @@ static int patch_update_file(struct add_p_state *s,
 				hunk_index = undecided_next;
 			else
 				err(s, _("No next hunk"));
+		} else if (s->answer.buf[0] == 'g') {
+			char *pend;
+			unsigned long response;
+
+			if (file_diff->hunk_nr < 2) {
+				err(s, _("No other hunks to goto"));
+				continue;
+			}
+			strbuf_remove(&s->answer, 0, 1);
+			strbuf_trim(&s->answer);
+			i = hunk_index - DISPLAY_HUNKS_LINES / 2;
+			if (i < file_diff->mode_change)
+				i = file_diff->mode_change;
+			while (s->answer.len == 0) {
+				i = display_hunks(s, file_diff, i);
+				printf("%s", i < file_diff->hunk_nr ?
+				       _("go to which hunk (<ret> to see "
+					 "more)? ") : _("go to which hunk? "));
+				fflush(stdout);
+				if (strbuf_getline(&s->answer,
+						   stdin) == EOF)
+					break;
+				strbuf_trim_trailing_newline(&s->answer);
+			}
+
+			strbuf_trim(&s->answer);
+			response = strtoul(s->answer.buf, &pend, 10);
+			if (*pend || pend == s->answer.buf)
+				err(s, _("Invalid number: '%s'"),
+				    s->answer.buf);
+			else if (0 < response && response <= file_diff->hunk_nr)
+				hunk_index = response - 1;
+			else
+				err(s, Q_("Sorry, only %d hunk available.",
+					  "Sorry, only %d hunks available.",
+					  file_diff->hunk_nr),
+				    (int)file_diff->hunk_nr);
 		} else if (s->answer.buf[0] == 's') {
 			size_t splittable_into = hunk->splittable_into;
 			if (splittable_into < 2)
diff --git a/t/t3701-add-interactive.sh b/t/t3701-add-interactive.sh
index fe383be50e..57c656a20c 100755
--- a/t/t3701-add-interactive.sh
+++ b/t/t3701-add-interactive.sh
@@ -413,6 +413,22 @@ test_expect_success 'split hunk setup' '
 	test_write_lines 10 15 20 21 22 23 24 30 40 50 60 >test
 '
 
+test_expect_success 'goto hunk' '
+	test_when_finished "git reset" &&
+	tr _ " " >expect <<-EOF &&
+	(2/2) Stage this hunk [y,n,q,a,d,K,g,/,e,?]? + 1:  -1,2 +1,3          +15
+	_ 2:  -2,4 +3,8          +21
+	go to which hunk? @@ -1,2 +1,3 @@
+	_10
+	+15
+	_20
+	(1/2) Stage this hunk [y,n,q,a,d,j,J,g,/,e,?]?_
+	EOF
+	test_write_lines s y g 1 | git add -p >actual &&
+	tail -n 7 <actual >actual.trimmed &&
+	test_cmp expect actual.trimmed
+'
+
 test_expect_success 'split hunk "add -p (edit)"' '
 	# Split, say Edit and do nothing.  Then:
 	#
-- 
gitgitgadget

[PATCH 16/19] built-in add -p: implement the '/' ("search regex") command

[Johannes Schindelin via GitGitGadget]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

This patch implements the hunk searching feature in the C version of
`git add -p`.

A test is added to verify that this behavior matches the one of the Perl
version of `git add -p`.

Note that this involves a change of behavior: the Perl version uses (of
course) the Perl flavor of regular expressions, while this patch uses
the regcomp()/regexec(), i.e. POSIX extended regular expressions. In
practice, this behavior change is unlikely to matter.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 add-patch.c                | 50 +++++++++++++++++++++++++++++++++++++-
 t/t3701-add-interactive.sh | 14 +++++++++++
 2 files changed, 63 insertions(+), 1 deletion(-)

diff --git a/add-patch.c b/add-patch.c
index fdbb1e3e22..fd72850c65 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -1013,6 +1013,7 @@ N_("y - stage this hunk\n"
    "k - leave this hunk undecided, see previous undecided hunk\n"
    "K - leave this hunk undecided, see previous hunk\n"
    "g - select a hunk to go to\n"
+   "/ - search for a hunk matching the given regex\n"
    "s - split the current hunk into smaller hunks\n"
    "e - manually edit the current hunk\n"
    "? - print help\n");
@@ -1072,7 +1073,7 @@ static int patch_update_file(struct add_p_state *s,
 		if (hunk_index + 1 < file_diff->hunk_nr)
 			strbuf_addstr(&s->buf, ",J");
 		if (file_diff->hunk_nr > 1)
-			strbuf_addstr(&s->buf, ",g");
+			strbuf_addstr(&s->buf, ",g,/");
 		if (hunk->splittable_into > 1)
 			strbuf_addstr(&s->buf, ",s");
 		if (hunk_index + 1 > file_diff->mode_change &&
@@ -1177,6 +1178,53 @@ static int patch_update_file(struct add_p_state *s,
 					  "Sorry, only %d hunks available.",
 					  file_diff->hunk_nr),
 				    (int)file_diff->hunk_nr);
+		} else if (s->answer.buf[0] == '/') {
+			regex_t regex;
+			int ret;
+
+			if (file_diff->hunk_nr < 2) {
+				err(s, _("No other hunks to search"));
+				continue;
+			}
+			strbuf_remove(&s->answer, 0, 1);
+			strbuf_trim_trailing_newline(&s->answer);
+			if (s->answer.len == 0) {
+				printf("%s", _("search for regex? "));
+				fflush(stdout);
+				if (strbuf_getline(&s->answer,
+						   stdin) == EOF)
+					break;
+				strbuf_trim_trailing_newline(&s->answer);
+				if (s->answer.len == 0)
+					continue;
+			}
+			ret = regcomp(&regex, s->answer.buf,
+				      REG_EXTENDED | REG_NOSUB | REG_NEWLINE);
+			if (ret) {
+				char errbuf[1024];
+
+				regerror(ret, &regex, errbuf, sizeof(errbuf));
+				err(s, _("Malformed search regexp %s: %s"),
+				    s->answer.buf, errbuf);
+				continue;
+			}
+			i = hunk_index;
+			for (;;) {
+				/* render the hunk into a scratch buffer */
+				render_hunk(s, file_diff->hunk + i, 0, 0,
+					    &s->buf);
+				if (regexec(&regex, s->buf.buf, 0, NULL, 0)
+				    != REG_NOMATCH)
+					break;
+				i++;
+				if (i == file_diff->hunk_nr)
+					i = 0;
+				if (i != hunk_index)
+					continue;
+				err(s, _("No hunk matches the given pattern"));
+				break;
+			}
+			hunk_index = i;
 		} else if (s->answer.buf[0] == 's') {
 			size_t splittable_into = hunk->splittable_into;
 			if (splittable_into < 2)
diff --git a/t/t3701-add-interactive.sh b/t/t3701-add-interactive.sh
index 57c656a20c..12ee321707 100755
--- a/t/t3701-add-interactive.sh
+++ b/t/t3701-add-interactive.sh
@@ -429,6 +429,20 @@ test_expect_success 'goto hunk' '
 	test_cmp expect actual.trimmed
 '
 
+test_expect_success 'navigate to hunk via regex' '
+	test_when_finished "git reset" &&
+	tr _ " " >expect <<-EOF &&
+	(2/2) Stage this hunk [y,n,q,a,d,K,g,/,e,?]? @@ -1,2 +1,3 @@
+	_10
+	+15
+	_20
+	(1/2) Stage this hunk [y,n,q,a,d,j,J,g,/,e,?]?_
+	EOF
+	test_write_lines s y /1,2 | git add -p >actual &&
+	tail -n 5 <actual >actual.trimmed &&
+	test_cmp expect actual.trimmed
+'
+
 test_expect_success 'split hunk "add -p (edit)"' '
 	# Split, say Edit and do nothing.  Then:
 	#
-- 
gitgitgadget

[PATCH 17/19] built-in add -p: implement the 'q' ("quit") command

[Johannes Schindelin via GitGitGadget]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

This command is actually very similar to the 'd' ("do not stage this
hunk or any of the later hunks in the file") command: it just does
something on top, namely leave the loop and return a value indicating
that we're quittin'.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 add-patch.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/add-patch.c b/add-patch.c
index fd72850c65..5e9829a8b4 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -12,9 +12,9 @@ enum prompt_mode_type {
 };
 
 static const char *prompt_mode[] = {
-	N_("Stage mode change [y,n,a,d%s,?]? "),
-	N_("Stage deletion [y,n,a,d%s,?]? "),
-	N_("Stage this hunk [y,n,a,d%s,?]? ")
+	N_("Stage mode change [y,n,a,q,d%s,?]? "),
+	N_("Stage deletion [y,n,a,q,d%s,?]? "),
+	N_("Stage this hunk [y,n,a,q,d%s,?]? ")
 };
 
 struct hunk_header {
@@ -1006,6 +1006,7 @@ static size_t display_hunks(struct add_p_state *s,
 static const char help_patch_text[] =
 N_("y - stage this hunk\n"
    "n - do not stage this hunk\n"
+   "q - quit; do not stage this hunk or any of the remaining ones\n"
    "a - stage this and all the remaining hunks\n"
    "d - do not stage this hunk nor any of the remaining hunks\n"
    "j - leave this hunk undecided, see next undecided hunk\n"
@@ -1026,7 +1027,7 @@ static int patch_update_file(struct add_p_state *s,
 	struct hunk *hunk;
 	char ch;
 	struct child_process cp = CHILD_PROCESS_INIT;
-	int colored = !!s->colored.len;
+	int colored = !!s->colored.len, quit = 0;
 	enum prompt_mode_type prompt_mode_type;
 
 	if (!file_diff->hunk_nr)
@@ -1115,12 +1116,16 @@ static int patch_update_file(struct add_p_state *s,
 				if (hunk->use == UNDECIDED_HUNK)
 					hunk->use = USE_HUNK;
 			}
-		} else if (ch == 'd') {
+		} else if (ch == 'd' || ch == 'q') {
 			for (; hunk_index < file_diff->hunk_nr; hunk_index++) {
 				hunk = file_diff->hunk + hunk_index;
 				if (hunk->use == UNDECIDED_HUNK)
 					hunk->use = SKIP_HUNK;
 			}
+			if (ch == 'q') {
+				quit = 1;
+				break;
+			}
 		} else if (s->answer.buf[0] == 'K') {
 			if (hunk_index)
 				hunk_index--;
@@ -1267,7 +1272,7 @@ static int patch_update_file(struct add_p_state *s,
 	}
 
 	putchar('\n');
-	return 0;
+	return quit;
 }
 
 int run_add_p(struct repository *r, const struct pathspec *ps)
-- 
gitgitgadget

[PATCH 18/19] built-in add -p: only show the applicable parts of the help text

[Johannes Schindelin via GitGitGadget]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

When displaying the only hunk in a file's diff, the prompt already
excludes the commands to navigate to the previous/next hunk.

Let's also let the `?` command show only the help lines corresponding to
the commands that are displayed in the prompt.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 add-patch.c | 32 ++++++++++++++++++++++++++++----
 1 file changed, 28 insertions(+), 4 deletions(-)

diff --git a/add-patch.c b/add-patch.c
index 5e9829a8b4..1eb0ab97bb 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -1008,8 +1008,10 @@ N_("y - stage this hunk\n"
    "n - do not stage this hunk\n"
    "q - quit; do not stage this hunk or any of the remaining ones\n"
    "a - stage this and all the remaining hunks\n"
-   "d - do not stage this hunk nor any of the remaining hunks\n"
-   "j - leave this hunk undecided, see next undecided hunk\n"
+   "d - do not stage this hunk nor any of the remaining hunks\n");
+
+static const char help_patch_remainder[] =
+N_("j - leave this hunk undecided, see next undecided hunk\n"
    "J - leave this hunk undecided, see next hunk\n"
    "k - leave this hunk undecided, see previous undecided hunk\n"
    "K - leave this hunk undecided, see previous hunk\n"
@@ -1246,9 +1248,31 @@ static int patch_update_file(struct add_p_state *s,
 				hunk->use = USE_HUNK;
 				goto soft_increment;
 			}
-		} else
-			color_fprintf(stdout, s->s.help_color,
+		} else {
+			const char *p = _(help_patch_remainder), *eol = p;
+
+			color_fprintf(stdout, s->s.help_color, "%s",
 				      _(help_patch_text));
+
+			/*
+			 * Show only those lines of the remainder that are
+			 * actually applicable with the current hunk.
+			 */
+			for (; *p; p = eol + (*eol == '\n')) {
+				eol = strchrnul(p, '\n');
+
+				/*
+				 * `s->buf` still contains the part of the
+				 * commands shown in the prompt that are not
+				 * always available.
+				 */
+				if (*p != '?' && !strchr(s->buf.buf, *p))
+					continue;
+
+				color_fprintf_ln(stdout, s->s.help_color,
+						 "%.*s", (int)(eol - p), p);
+			}
+		}
 	}
 
 	/* Any hunk to be used? */
-- 
gitgitgadget

[PATCH 19/19] built-in add -p: show helpful hint when nothing can be staged

[Johannes Schindelin via GitGitGadget]

From: Johannes Schindelin <johannes.schindelin@gmx.de>

This patch will make `git add -p` show "No changes." or "Only binary
files changed." in that case.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 add-patch.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/add-patch.c b/add-patch.c
index 1eb0ab97bb..2c46fe5b33 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -44,7 +44,7 @@ struct add_p_state {
 		struct hunk head;
 		struct hunk *hunk;
 		size_t hunk_nr, hunk_alloc;
-		unsigned deleted:1, mode_change:1;
+		unsigned deleted:1, mode_change:1,binary:1;
 	} *file_diff;
 	size_t file_diff_nr;
 };
@@ -294,7 +294,9 @@ static int parse_diff(struct add_p_state *s, const struct pathspec *ps)
 				BUG("'new mode' does not immediately follow "
 				    "'old mode'?\n\n%.*s",
 				    (int)(eol - plain->buf), plain->buf);
-		}
+		} else if (hunk == &file_diff->head &&
+			   starts_with(p, "Binary files "))
+			file_diff->binary = 1;
 
 		if (file_diff->deleted && file_diff->mode_change)
 			BUG("diff contains delete *and* a mode change?!?\n%.*s",
@@ -1304,7 +1306,7 @@ int run_add_p(struct repository *r, const struct pathspec *ps)
 	struct add_p_state s = {
 		{ r }, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT
 	};
-	size_t i;
+	size_t i, binary_count = 0;
 
 	init_add_i_state(&s.s, r);
 
@@ -1318,9 +1320,16 @@ int run_add_p(struct repository *r, const struct pathspec *ps)
 	}
 
 	for (i = 0; i < s.file_diff_nr; i++)
-		if (patch_update_file(&s, s.file_diff + i))
+		if (s.file_diff[i].binary && !s.file_diff[i].hunk_nr)
+			binary_count++;
+		else if (patch_update_file(&s, s.file_diff + i))
 			break;
 
+	if (s.file_diff_nr == 0)
+		fprintf(stderr, _("No changes.\n"));
+	else if (binary_count == s.file_diff_nr)
+		fprintf(stderr, _("Only binary files changed.\n"));
+
 	strbuf_release(&s.answer);
 	strbuf_release(&s.buf);
 	strbuf_release(&s.plain);
-- 
gitgitgadget