[PATCH 1/2] parse-options: make CMDMODE errors more precise

[PATCH 1/2] parse-options: make CMDMODE errors more precise

[René Scharfe]

Only a single PARSE_OPT_CMDMODE option can be specified for the same
variable at the same time.  This is enforced by get_value(), but the
error messages are imprecise in three ways:

1. If a non-PARSE_OPT_CMDMODE option changes the value variable of a
PARSE_OPT_CMDMODE option then an ominously vague message is shown:

   $ t/helper/test-tool parse-options --set23 --mode1
   error: option `mode1' : incompatible with something else

Worse: If the order of options is reversed then no error is reported at
all:

   $ t/helper/test-tool parse-options --mode1 --set23
   boolean: 0
   integer: 23
   magnitude: 0
   timestamp: 0
   string: (not set)
   abbrev: 7
   verbose: -1
   quiet: 0
   dry run: no
   file: (not set)

Fortunately this can currently only happen in the test helper; actual
Git commands don't share the same variable for the value of options with
and without the flag PARSE_OPT_CMDMODE.

2. If there are multiple options with the same value (synonyms), then
the one that is defined first is shown rather than the one actually
given on the command line, which is confusing:

   $ git am --resolved --quit
   error: option `quit' is incompatible with --continue

3. Arguments of PARSE_OPT_CMDMODE options are not handled by the
parse-option machinery.  This is left to the callback function.  We
currently only have a single affected option, --show-current-patch of
git am.  Errors for it can show an argument that was not actually given
on the command line:

   $ git am --show-current-patch --show-current-patch=diff
   error: options '--show-current-patch=diff' and '--show-current-patch=raw' cannot be used together

The options --show-current-patch and --show-current-patch=raw are
synonyms, but the error accuses the user of input they did not actually
made.  Or it can awkwardly print a NULL pointer:

   $ git am --show-current-patch=diff --show-current-patch
   error: options '--show-current-patch=(null)' and '--show-current-patch=diff' cannot be used together

The reasons for these shortcomings is that the current code checks
incompatibility only when encountering a PARSE_OPT_CMDMODE option at the
command line, and that it searches the previous incompatible option by
value.

Fix the first two points by checking all PARSE_OPT_CMDMODE variables
after parsing each option and by storing all relevant details if their
value changed.  Do that whether or not the changing options has the flag
PARSE_OPT_CMDMODE set.  Report an incompatibility only if two options
change the variable to different values and at least one of them is a
PARSE_OPT_CMDMODE option.  This changes the output of the first three
examples above to:

   $ t/helper/test-tool parse-options --set23 --mode1
   error: --mode1 is incompatible with --set23
   $ t/helper/test-tool parse-options --mode1 --set23
   error: --set23 is incompatible with --mode1
   $ git am --resolved --quit
   error: --quit is incompatible with --resolved

Store the argument of PARSE_OPT_CMDMODE options of type OPTION_CALLBACK
as well to allow taking over the responsibility for compatibility
checking from the callback function.  The next patch will use this
capability to fix the messages for git am --show-current-patch.

Use a linked list for storing the PARSE_OPT_CMDMODE variables.  This
somewhat outdated data structure is simple and suffices, as the number
of elements per command is currently only zero or one.  We do support
multiple different command modes variables per command, but I don't
expect that we'd ever use a significant number of them.  Once we do we
can switch to a hashmap.

Since we no longer need to search the conflicting option, the all_opts
parameter of get_value() is no longer used.  Remove it.

Extend the tests to check for both conflicting option names, but don't
insist on a particular order.

Signed-off-by: René Scharfe <l.s.r@web.de>
---
 parse-options.c               | 144 ++++++++++++++++++++++------------
 parse-options.h               |   3 +
 t/helper/test-parse-options.c |  16 ++++
 t/t0040-parse-options.sh      |  33 ++++++--
 4 files changed, 139 insertions(+), 57 deletions(-)

diff --git a/parse-options.c b/parse-options.c
index 093eaf2db8..e0c94b0546 100644
--- a/parse-options.c
+++ b/parse-options.c
@@ -70,42 +70,10 @@ static void fix_filename(const char *prefix, char **file)
 		*file = prefix_filename_except_for_dash(prefix, *file);
 }

-static enum parse_opt_result opt_command_mode_error(
-	const struct option *opt,
-	const struct option *all_opts,
-	enum opt_parsed flags)
-{
-	const struct option *that;
-	struct strbuf that_name = STRBUF_INIT;
-
-	/*
-	 * Find the other option that was used to set the variable
-	 * already, and report that this is not compatible with it.
-	 */
-	for (that = all_opts; that->type != OPTION_END; that++) {
-		if (that == opt ||
-		    !(that->flags & PARSE_OPT_CMDMODE) ||
-		    that->value != opt->value ||
-		    that->defval != *(int *)opt->value)
-			continue;
-
-		if (that->long_name)
-			strbuf_addf(&that_name, "--%s", that->long_name);
-		else
-			strbuf_addf(&that_name, "-%c", that->short_name);
-		error(_("%s is incompatible with %s"),
-		      optname(opt, flags), that_name.buf);
-		strbuf_release(&that_name);
-		return PARSE_OPT_ERROR;
-	}
-	return error(_("%s : incompatible with something else"),
-		     optname(opt, flags));
-}
-
-static enum parse_opt_result get_value(struct parse_opt_ctx_t *p,
-				       const struct option *opt,
-				       const struct option *all_opts,
-				       enum opt_parsed flags)
+static enum parse_opt_result do_get_value(struct parse_opt_ctx_t *p,
+					  const struct option *opt,
+					  enum opt_parsed flags,
+					  const char **argp)
 {
 	const char *s, *arg;
 	const int unset = flags & OPT_UNSET;
@@ -118,14 +86,6 @@ static enum parse_opt_result get_value(struct parse_opt_ctx_t *p,
 	if (!(flags & OPT_SHORT) && p->opt && (opt->flags & PARSE_OPT_NOARG))
 		return error(_("%s takes no value"), optname(opt, flags));

-	/*
-	 * Giving the same mode option twice, although unnecessary,
-	 * is not a grave error, so let it pass.
-	 */
-	if ((opt->flags & PARSE_OPT_CMDMODE) &&
-	    *(int *)opt->value && *(int *)opt->value != opt->defval)
-		return opt_command_mode_error(opt, all_opts, flags);
-
 	switch (opt->type) {
 	case OPTION_LOWLEVEL_CALLBACK:
 		return opt->ll_callback(p, opt, NULL, unset);
@@ -200,6 +160,8 @@ static enum parse_opt_result get_value(struct parse_opt_ctx_t *p,
 			p_unset = 0;
 			p_arg = arg;
 		}
+		if (opt->flags & PARSE_OPT_CMDMODE)
+			*argp = p_arg;
 		if (opt->callback)
 			return (*opt->callback)(opt, p_arg, p_unset) ? (-1) : 0;
 		else
@@ -247,16 +209,91 @@ static enum parse_opt_result get_value(struct parse_opt_ctx_t *p,
 	}
 }

+struct parse_opt_cmdmode_list {
+	int value, *value_ptr;
+	const struct option *opt;
+	const char *arg;
+	enum opt_parsed flags;
+	struct parse_opt_cmdmode_list *next;
+};
+
+static void build_cmdmode_list(struct parse_opt_ctx_t *ctx,
+			       const struct option *opts)
+{
+	ctx->cmdmode_list = NULL;
+
+	for (; opts->type != OPTION_END; opts++) {
+		struct parse_opt_cmdmode_list *elem = ctx->cmdmode_list;
+		int *value_ptr = opts->value;
+
+		if (!(opts->flags & PARSE_OPT_CMDMODE) || !value_ptr)
+			continue;
+
+		while (elem && elem->value_ptr != value_ptr)
+			elem = elem->next;
+		if (elem)
+			continue;
+
+		CALLOC_ARRAY(elem, 1);
+		elem->value_ptr = value_ptr;
+		elem->value = *value_ptr;
+		elem->next = ctx->cmdmode_list;
+		ctx->cmdmode_list = elem;
+	}
+}
+
+static char *optnamearg(const struct option *opt, const char *arg,
+			enum opt_parsed flags)
+{
+	if (flags & OPT_SHORT)
+		return xstrfmt("-%c%s", opt->short_name, arg ? arg : "");
+	return xstrfmt("--%s%s%s%s", flags & OPT_UNSET ? "no-" : "",
+		       opt->long_name, arg ? "=" : "", arg ? arg : "");
+}
+
+static enum parse_opt_result get_value(struct parse_opt_ctx_t *p,
+				       const struct option *opt,
+				       enum opt_parsed flags)
+{
+	const char *arg = NULL;
+	enum parse_opt_result result = do_get_value(p, opt, flags, &arg);
+	struct parse_opt_cmdmode_list *elem = p->cmdmode_list;
+	char *opt_name, *other_opt_name;
+
+	for (; elem; elem = elem->next) {
+		if (*elem->value_ptr == elem->value)
+			continue;
+
+		if (elem->opt &&
+		    (elem->opt->flags | opt->flags) & PARSE_OPT_CMDMODE)
+			break;
+
+		elem->opt = opt;
+		elem->arg = arg;
+		elem->flags = flags;
+		elem->value = *elem->value_ptr;
+	}
+
+	if (result || !elem)
+		return result;
+
+	opt_name = optnamearg(opt, arg, flags);
+	other_opt_name = optnamearg(elem->opt, elem->arg, elem->flags);
+	error(_("%s is incompatible with %s"), opt_name, other_opt_name);
+	free(opt_name);
+	free(other_opt_name);
+	return -1;
+}
+
 static enum parse_opt_result parse_short_opt(struct parse_opt_ctx_t *p,
 					     const struct option *options)
 {
-	const struct option *all_opts = options;
 	const struct option *numopt = NULL;

 	for (; options->type != OPTION_END; options++) {
 		if (options->short_name == *p->opt) {
 			p->opt = p->opt[1] ? p->opt + 1 : NULL;
-			return get_value(p, options, all_opts, OPT_SHORT);
+			return get_value(p, options, OPT_SHORT);
 		}

 		/*
@@ -318,7 +355,6 @@ static enum parse_opt_result parse_long_opt(
 	struct parse_opt_ctx_t *p, const char *arg,
 	const struct option *options)
 {
-	const struct option *all_opts = options;
 	const char *arg_end = strchrnul(arg, '=');
 	const struct option *abbrev_option = NULL, *ambiguous_option = NULL;
 	enum opt_parsed abbrev_flags = OPT_LONG, ambiguous_flags = OPT_LONG;
@@ -387,7 +423,7 @@ static enum parse_opt_result parse_long_opt(
 				continue;
 			p->opt = rest + 1;
 		}
-		return get_value(p, options, all_opts, flags ^ opt_flags);
+		return get_value(p, options, flags ^ opt_flags);
 	}

 	if (disallow_abbreviated_options && (ambiguous_option || abbrev_option))
@@ -405,7 +441,7 @@ static enum parse_opt_result parse_long_opt(
 		return PARSE_OPT_HELP;
 	}
 	if (abbrev_option)
-		return get_value(p, abbrev_option, all_opts, abbrev_flags);
+		return get_value(p, abbrev_option, abbrev_flags);
 	return PARSE_OPT_UNKNOWN;
 }

@@ -413,13 +449,11 @@ static enum parse_opt_result parse_nodash_opt(struct parse_opt_ctx_t *p,
 					      const char *arg,
 					      const struct option *options)
 {
-	const struct option *all_opts = options;
-
 	for (; options->type != OPTION_END; options++) {
 		if (!(options->flags & PARSE_OPT_NODASH))
 			continue;
 		if (options->short_name == arg[0] && arg[1] == '\0')
-			return get_value(p, options, all_opts, OPT_SHORT);
+			return get_value(p, options, OPT_SHORT);
 	}
 	return PARSE_OPT_ERROR;
 }
@@ -574,6 +608,7 @@ static void parse_options_start_1(struct parse_opt_ctx_t *ctx,
 	    (flags & PARSE_OPT_KEEP_ARGV0))
 		BUG("Can't keep argv0 if you don't have it");
 	parse_options_check(options);
+	build_cmdmode_list(ctx, options);
 }

 void parse_options_start(struct parse_opt_ctx_t *ctx,
@@ -1006,6 +1041,11 @@ int parse_options(int argc, const char **argv,
 	precompose_argv_prefix(argc, argv, NULL);
 	free_preprocessed_options(real_options);
 	free(ctx.alias_groups);
+	for (struct parse_opt_cmdmode_list *elem = ctx.cmdmode_list; elem;) {
+		struct parse_opt_cmdmode_list *next = elem->next;
+		free(elem);
+		elem = next;
+	}
 	return parse_options_end(&ctx);
 }

diff --git a/parse-options.h b/parse-options.h
index 4a66ec3bf5..bd62e20268 100644
--- a/parse-options.h
+++ b/parse-options.h
@@ -445,6 +445,8 @@ static inline void die_for_incompatible_opt3(int opt1, const char *opt1_name,

 /*----- incremental advanced APIs -----*/

+struct parse_opt_cmdmode_list;
+
 /*
  * It's okay for the caller to consume argv/argc in the usual way.
  * Other fields of that structure are private to parse-options and should not
@@ -459,6 +461,7 @@ struct parse_opt_ctx_t {
 	unsigned has_subcommands;
 	const char *prefix;
 	const char **alias_groups; /* must be in groups of 3 elements! */
+	struct parse_opt_cmdmode_list *cmdmode_list;
 };

 void parse_options_start(struct parse_opt_ctx_t *ctx,
diff --git a/t/helper/test-parse-options.c b/t/helper/test-parse-options.c
index a4f6e24b0c..ded8116cc5 100644
--- a/t/helper/test-parse-options.c
+++ b/t/helper/test-parse-options.c
@@ -21,6 +21,19 @@ static struct {
 	int unset;
 } length_cb;

+static int mode34_callback(const struct option *opt, const char *arg, int unset)
+{
+	if (unset)
+		*(int *)opt->value = 0;
+	else if (!strcmp(arg, "3"))
+		*(int *)opt->value = 3;
+	else if (!strcmp(arg, "4"))
+		*(int *)opt->value = 4;
+	else
+		return error("invalid value for '%s': '%s'", "--mode34", arg);
+	return 0;
+}
+
 static int length_callback(const struct option *opt, const char *arg, int unset)
 {
 	length_cb.called = 1;
@@ -124,6 +137,9 @@ int cmd__parse_options(int argc, const char **argv)
 		OPT_SET_INT(0, "set23", &integer, "set integer to 23", 23),
 		OPT_CMDMODE(0, "mode1", &integer, "set integer to 1 (cmdmode option)", 1),
 		OPT_CMDMODE(0, "mode2", &integer, "set integer to 2 (cmdmode option)", 2),
+		OPT_CALLBACK_F(0, "mode34", &integer, "(3|4)",
+			"set integer to 3 or 4 (cmdmode option)",
+			PARSE_OPT_CMDMODE, mode34_callback),
 		OPT_CALLBACK('L', "length", &integer, "str",
 			"get length of <str>", length_callback),
 		OPT_FILENAME('F', "file", &file, "set file to <file>"),
diff --git a/t/t0040-parse-options.sh b/t/t0040-parse-options.sh
index a0ad6192d6..06fb9e6457 100755
--- a/t/t0040-parse-options.sh
+++ b/t/t0040-parse-options.sh
@@ -28,6 +28,7 @@ usage: test-tool parse-options <options>
     --[no-]set23          set integer to 23
     --mode1               set integer to 1 (cmdmode option)
     --mode2               set integer to 2 (cmdmode option)
+    --[no-]mode34 (3|4)   set integer to 3 or 4 (cmdmode option)
     -L, --[no-]length <str>
                           get length of <str>
     -F, --[no-]file <file>
@@ -366,19 +367,41 @@ test_expect_success 'OPT_NEGBIT() works' '
 '

 test_expect_success 'OPT_CMDMODE() works' '
-	test-tool parse-options --expect="integer: 1" --mode1
+	test-tool parse-options --expect="integer: 1" --mode1 &&
+	test-tool parse-options --expect="integer: 3" --mode34=3
 '

-test_expect_success 'OPT_CMDMODE() detects incompatibility' '
+test_expect_success 'OPT_CMDMODE() detects incompatibility (1)' '
 	test_must_fail test-tool parse-options --mode1 --mode2 >output 2>output.err &&
 	test_must_be_empty output &&
-	test_i18ngrep "incompatible with --mode" output.err
+	test_i18ngrep "mode1" output.err &&
+	test_i18ngrep "mode2" output.err &&
+	test_i18ngrep "is incompatible with" output.err
 '

-test_expect_success 'OPT_CMDMODE() detects incompatibility with something else' '
+test_expect_success 'OPT_CMDMODE() detects incompatibility (2)' '
 	test_must_fail test-tool parse-options --set23 --mode2 >output 2>output.err &&
 	test_must_be_empty output &&
-	test_i18ngrep "incompatible with something else" output.err
+	test_i18ngrep "mode2" output.err &&
+	test_i18ngrep "set23" output.err &&
+	test_i18ngrep "is incompatible with" output.err
+'
+
+test_expect_success 'OPT_CMDMODE() detects incompatibility (3)' '
+	test_must_fail test-tool parse-options --mode2 --set23 >output 2>output.err &&
+	test_must_be_empty output &&
+	test_i18ngrep "mode2" output.err &&
+	test_i18ngrep "set23" output.err &&
+	test_i18ngrep "is incompatible with" output.err
+'
+
+test_expect_success 'OPT_CMDMODE() detects incompatibility (4)' '
+	test_must_fail test-tool parse-options --mode2 --mode34=3 \
+		>output 2>output.err &&
+	test_must_be_empty output &&
+	test_i18ngrep "mode2" output.err &&
+	test_i18ngrep "mode34.3" output.err &&
+	test_i18ngrep "is incompatible with" output.err
 '

 test_expect_success 'OPT_COUNTUP() with PARSE_OPT_NODASH works' '
--
2.42.0

[PATCH 2/2] am: simplify --show-current-patch handling

[René Scharfe]

Let the parse-options code detect and handle the use of options that are
incompatible with --show-current-patch.  This requires exposing the
distinction between the "raw" and "diff" sub-modes.  Do that by
splitting the mode RESUME_SHOW_PATCH into RESUME_SHOW_PATCH_RAW and
RESUME_SHOW_PATCH_DIFF and stop tracking sub-modes in a separate struct.

The result is a simpler callback function and more precise error
messages.  The original reports a spurious argument or a NULL pointer:

   $ git am --show-current-patch --show-current-patch=diff
   error: options '--show-current-patch=diff' and '--show-current-patch=raw' cannot be used together
   $ git am --show-current-patch=diff --show-current-patch
   error: options '--show-current-patch=(null)' and '--show-current-patch=diff' cannot be used together

With this patch we get the more precise:

   $ git am --show-current-patch --show-current-patch=diff
   error: --show-current-patch=diff is incompatible with --show-current-patch
   $ git am --show-current-patch=diff --show-current-patch
   error: --show-current-patch is incompatible with --show-current-patch=diff

Signed-off-by: René Scharfe <l.s.r@web.de>
---
 builtin/am.c | 112 ++++++++++++++++++++-------------------------------
 1 file changed, 44 insertions(+), 68 deletions(-)

diff --git a/builtin/am.c b/builtin/am.c
index 6655059a57..ef5b9459af 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -92,9 +92,16 @@ enum signoff_type {
 	SIGNOFF_EXPLICIT /* --signoff was set on the command-line */
 };

-enum show_patch_type {
-	SHOW_PATCH_RAW = 0,
-	SHOW_PATCH_DIFF = 1,
+enum resume_type {
+	RESUME_FALSE = 0,
+	RESUME_APPLY,
+	RESUME_RESOLVED,
+	RESUME_SKIP,
+	RESUME_ABORT,
+	RESUME_QUIT,
+	RESUME_SHOW_PATCH_RAW,
+	RESUME_SHOW_PATCH_DIFF,
+	RESUME_ALLOW_EMPTY,
 };

 enum empty_action {
@@ -2191,7 +2198,7 @@ static void am_abort(struct am_state *state)
 	am_destroy(state);
 }

-static int show_patch(struct am_state *state, enum show_patch_type sub_mode)
+static int show_patch(struct am_state *state, enum resume_type resume_mode)
 {
 	struct strbuf sb = STRBUF_INIT;
 	const char *patch_path;
@@ -2206,11 +2213,11 @@ static int show_patch(struct am_state *state, enum show_patch_type sub_mode)
 		return run_command(&cmd);
 	}

-	switch (sub_mode) {
-	case SHOW_PATCH_RAW:
+	switch (resume_mode) {
+	case RESUME_SHOW_PATCH_RAW:
 		patch_path = am_path(state, msgnum(state));
 		break;
-	case SHOW_PATCH_DIFF:
+	case RESUME_SHOW_PATCH_DIFF:
 		patch_path = am_path(state, "patch");
 		break;
 	default:
@@ -2257,57 +2264,25 @@ static int parse_opt_patchformat(const struct option *opt, const char *arg, int
 	return 0;
 }

-enum resume_type {
-	RESUME_FALSE = 0,
-	RESUME_APPLY,
-	RESUME_RESOLVED,
-	RESUME_SKIP,
-	RESUME_ABORT,
-	RESUME_QUIT,
-	RESUME_SHOW_PATCH,
-	RESUME_ALLOW_EMPTY,
-};
-
-struct resume_mode {
-	enum resume_type mode;
-	enum show_patch_type sub_mode;
-};
-
 static int parse_opt_show_current_patch(const struct option *opt, const char *arg, int unset)
 {
 	int *opt_value = opt->value;
-	struct resume_mode *resume = container_of(opt_value, struct resume_mode, mode);

+	BUG_ON_OPT_NEG(unset);
+
+	if (!arg)
+		*opt_value = opt->defval;
+	else if (!strcmp(arg, "raw"))
+		*opt_value = RESUME_SHOW_PATCH_RAW;
+	else if (!strcmp(arg, "diff"))
+		*opt_value = RESUME_SHOW_PATCH_DIFF;
 	/*
 	 * Please update $__git_showcurrentpatch in git-completion.bash
 	 * when you add new options
 	 */
-	const char *valid_modes[] = {
-		[SHOW_PATCH_DIFF] = "diff",
-		[SHOW_PATCH_RAW] = "raw"
-	};
-	int new_value = SHOW_PATCH_RAW;
-
-	BUG_ON_OPT_NEG(unset);
-
-	if (arg) {
-		for (new_value = 0; new_value < ARRAY_SIZE(valid_modes); new_value++) {
-			if (!strcmp(arg, valid_modes[new_value]))
-				break;
-		}
-		if (new_value >= ARRAY_SIZE(valid_modes))
-			return error(_("invalid value for '%s': '%s'"),
-				     "--show-current-patch", arg);
-	}
-
-	if (resume->mode == RESUME_SHOW_PATCH && new_value != resume->sub_mode)
-		return error(_("options '%s=%s' and '%s=%s' "
-					   "cannot be used together"),
-			     "--show-current-patch", arg,
-			     "--show-current-patch", valid_modes[resume->sub_mode]);
-
-	resume->mode = RESUME_SHOW_PATCH;
-	resume->sub_mode = new_value;
+	else
+		return error(_("invalid value for '%s': '%s'"),
+			     "--show-current-patch", arg);
 	return 0;
 }

@@ -2317,7 +2292,7 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 	int binary = -1;
 	int keep_cr = -1;
 	int patch_format = PATCH_FORMAT_UNKNOWN;
-	struct resume_mode resume = { .mode = RESUME_FALSE };
+	enum resume_type resume_mode = RESUME_FALSE;
 	int in_progress;
 	int ret = 0;

@@ -2388,27 +2363,27 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 			PARSE_OPT_NOARG),
 		OPT_STRING(0, "resolvemsg", &state.resolvemsg, NULL,
 			N_("override error message when patch failure occurs")),
-		OPT_CMDMODE(0, "continue", &resume.mode,
+		OPT_CMDMODE(0, "continue", &resume_mode,
 			N_("continue applying patches after resolving a conflict"),
 			RESUME_RESOLVED),
-		OPT_CMDMODE('r', "resolved", &resume.mode,
+		OPT_CMDMODE('r', "resolved", &resume_mode,
 			N_("synonyms for --continue"),
 			RESUME_RESOLVED),
-		OPT_CMDMODE(0, "skip", &resume.mode,
+		OPT_CMDMODE(0, "skip", &resume_mode,
 			N_("skip the current patch"),
 			RESUME_SKIP),
-		OPT_CMDMODE(0, "abort", &resume.mode,
+		OPT_CMDMODE(0, "abort", &resume_mode,
 			N_("restore the original branch and abort the patching operation"),
 			RESUME_ABORT),
-		OPT_CMDMODE(0, "quit", &resume.mode,
+		OPT_CMDMODE(0, "quit", &resume_mode,
 			N_("abort the patching operation but keep HEAD where it is"),
 			RESUME_QUIT),
-		{ OPTION_CALLBACK, 0, "show-current-patch", &resume.mode,
+		{ OPTION_CALLBACK, 0, "show-current-patch", &resume_mode,
 		  "(diff|raw)",
 		  N_("show the patch being applied"),
 		  PARSE_OPT_CMDMODE | PARSE_OPT_OPTARG | PARSE_OPT_NONEG | PARSE_OPT_LITERAL_ARGHELP,
-		  parse_opt_show_current_patch, RESUME_SHOW_PATCH },
-		OPT_CMDMODE(0, "allow-empty", &resume.mode,
+		  parse_opt_show_current_patch, RESUME_SHOW_PATCH_RAW },
+		OPT_CMDMODE(0, "allow-empty", &resume_mode,
 			N_("record the empty patch as an empty commit"),
 			RESUME_ALLOW_EMPTY),
 		OPT_BOOL(0, "committer-date-is-author-date",
@@ -2463,12 +2438,12 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		 *    intend to feed us a patch but wanted to continue
 		 *    unattended.
 		 */
-		if (argc || (resume.mode == RESUME_FALSE && !isatty(0)))
+		if (argc || (resume_mode == RESUME_FALSE && !isatty(0)))
 			die(_("previous rebase directory %s still exists but mbox given."),
 				state.dir);

-		if (resume.mode == RESUME_FALSE)
-			resume.mode = RESUME_APPLY;
+		if (resume_mode == RESUME_FALSE)
+			resume_mode = RESUME_APPLY;

 		if (state.signoff == SIGNOFF_EXPLICIT)
 			am_append_signoff(&state);
@@ -2482,7 +2457,7 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		 * stray directories.
 		 */
 		if (file_exists(state.dir) && !state.rebasing) {
-			if (resume.mode == RESUME_ABORT || resume.mode == RESUME_QUIT) {
+			if (resume_mode == RESUME_ABORT || resume_mode == RESUME_QUIT) {
 				am_destroy(&state);
 				am_state_release(&state);
 				return 0;
@@ -2493,7 +2468,7 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 				state.dir);
 		}

-		if (resume.mode)
+		if (resume_mode)
 			die(_("Resolve operation not in progress, we are not resuming."));

 		for (i = 0; i < argc; i++) {
@@ -2511,7 +2486,7 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		strvec_clear(&paths);
 	}

-	switch (resume.mode) {
+	switch (resume_mode) {
 	case RESUME_FALSE:
 		am_run(&state, 0);
 		break;
@@ -2520,7 +2495,7 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		break;
 	case RESUME_RESOLVED:
 	case RESUME_ALLOW_EMPTY:
-		am_resolve(&state, resume.mode == RESUME_ALLOW_EMPTY ? 1 : 0);
+		am_resolve(&state, resume_mode == RESUME_ALLOW_EMPTY ? 1 : 0);
 		break;
 	case RESUME_SKIP:
 		am_skip(&state);
@@ -2532,8 +2507,9 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		am_rerere_clear();
 		am_destroy(&state);
 		break;
-	case RESUME_SHOW_PATCH:
-		ret = show_patch(&state, resume.sub_mode);
+	case RESUME_SHOW_PATCH_RAW:
+	case RESUME_SHOW_PATCH_DIFF:
+		ret = show_patch(&state, resume_mode);
 		break;
 	default:
 		BUG("invalid resume value");
--
2.42.0

Re: [PATCH 1/2] parse-options: make CMDMODE errors more precise

[Junio C Hamano]

René Scharfe <l.s.r@web.de> writes:

> Store the argument of PARSE_OPT_CMDMODE options of type OPTION_CALLBACK
> as well to allow taking over the responsibility for compatibility
> checking from the callback function.  The next patch will use this
> capability to fix the messages for git am --show-current-patch.
>
> Use a linked list for storing the PARSE_OPT_CMDMODE variables.  This
> somewhat outdated data structure is simple and suffices, as the number
> of elements per command is currently only zero or one.  We do support
> multiple different command modes variables per command, but I don't
> expect that we'd ever use a significant number of them.  Once we do we
> can switch to a hashmap.

Makes quite a lot of sense.  I would have expected to see this in
the parse_options_check() function, where other sanity checks are
done, but I think the reason you added the call to its caller
because parse_options_check() does not take the context.

It is not like we want to perform a sanity check that is independent
from a particular invocation of parse_options() on the options[]
array only just once, and want to reuse the array that is known to
be sane multiple times.  The check is called once for every
invocation, so with or without this change, I do not see a good
reason for parse_options_check() not to take context, though.

> +static enum parse_opt_result get_value(struct parse_opt_ctx_t *p,
> +				       const struct option *opt,
> +				       enum opt_parsed flags)
> +{
> +	const char *arg = NULL;
> +	enum parse_opt_result result = do_get_value(p, opt, flags, &arg);
> +	struct parse_opt_cmdmode_list *elem = p->cmdmode_list;
> +	char *opt_name, *other_opt_name;
> +
> +	for (; elem; elem = elem->next) {
> +		if (*elem->value_ptr == elem->value)
> +			continue;
> +
> +		if (elem->opt &&
> +		    (elem->opt->flags | opt->flags) & PARSE_OPT_CMDMODE)
> +			break;
> +
> +		elem->opt = opt;
> +		elem->arg = arg;
> +		elem->flags = flags;
> +		elem->value = *elem->value_ptr;
> +	}
> +
> +	if (result || !elem)
> +		return result;
> +
> +	opt_name = optnamearg(opt, arg, flags);
> +	other_opt_name = optnamearg(elem->opt, elem->arg, elem->flags);
> +	error(_("%s is incompatible with %s"), opt_name, other_opt_name);
> +	free(opt_name);
> +	free(other_opt_name);
> +	return -1;
> +}

Looks quite involved but the overhead is number of supported cmdmode
options per each command line option, and the problems outlined in
the proposed log message are worth addressing.  OK.

> @@ -1006,6 +1041,11 @@ int parse_options(int argc, const char **argv,
>  	precompose_argv_prefix(argc, argv, NULL);
>  	free_preprocessed_options(real_options);
>  	free(ctx.alias_groups);
> +	for (struct parse_opt_cmdmode_list *elem = ctx.cmdmode_list; elem;) {
> +		struct parse_opt_cmdmode_list *next = elem->next;
> +		free(elem);
> +		elem = next;
> +	}
>  	return parse_options_end(&ctx);
>  }

OK.