Merge branch 'jk/c23-const-preserving-fixes'

Adjust the codebase for C23 that changes functions like strchr()
that discarded constness when they return a pointer into a const
string to preserve constness.

* jk/c23-const-preserving-fixes:
  config: store allocated string in non-const pointer
  rev-parse: avoid writing to const string for parent marks
  revision: avoid writing to const string for parent marks
  rev-parse: simplify dotdot parsing
  revision: make handle_dotdot() interface less confusing

3 files changed, 58 insertions, 56 deletions

diff --git a/builtin/config.c b/builtin/config.c
index 7c4857be62..cf4ba0f7cc 100644
--- a/builtin/config.c
+++ b/builtin/config.c
@@ -838,6 +838,7 @@ static int get_urlmatch(const struct config_location_options *opts,
 			const char *var, const char *url)
 {
 	int ret;
+	char *section;
 	char *section_tail;
 	struct config_display_options display_opts = *_display_opts;
 	struct string_list_item *item;
@@ -851,8 +852,8 @@ static int get_urlmatch(const struct config_location_options *opts,
 	if (!url_normalize(url, &config.url))
 		die("%s", config.url.err);
 
-	config.section = xstrdup_tolower(var);
-	section_tail = strchr(config.section, '.');
+	config.section = section = xstrdup_tolower(var);
+	section_tail = strchr(section, '.');
 	if (section_tail) {
 		*section_tail = '\0';
 		config.key = section_tail + 1;
@@ -886,7 +887,7 @@ static int get_urlmatch(const struct config_location_options *opts,
 	string_list_clear(&values, 1);
 	free(config.url.url);
 
-	free((void *)config.section);
+	free(section);
 	return ret;
 }
 
diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
index 01a62800e8..218b5f34d6 100644
--- a/builtin/rev-parse.c
+++ b/builtin/rev-parse.c
@@ -267,21 +267,20 @@ static int show_file(const char *arg, int output_prefix)
 
 static int try_difference(const char *arg)
 {
-	char *dotdot;
+	const char *dotdot;
 	struct object_id start_oid;
 	struct object_id end_oid;
 	const char *end;
 	const char *start;
+	char *to_free;
 	int symmetric;
 	static const char head_by_default[] = "HEAD";
 
 	if (!(dotdot = strstr(arg, "..")))
 		return 0;
+	start = to_free = xmemdupz(arg, dotdot - arg);
 	end = dotdot + 2;
-	start = arg;
 	symmetric = (*end == '.');
-
-	*dotdot = 0;
 	end += symmetric;
 
 	if (!*end)
@@ -295,7 +294,7 @@ static int try_difference(const char *arg)
 		 * Just ".."?  That is not a range but the
 		 * pathspec for the parent directory.
 		 */
-		*dotdot = '.';
+		free(to_free);
 		return 0;
 	}
 
@@ -308,7 +307,7 @@ static int try_difference(const char *arg)
 			a = lookup_commit_reference(the_repository, &start_oid);
 			b = lookup_commit_reference(the_repository, &end_oid);
 			if (!a || !b) {
-				*dotdot = '.';
+				free(to_free);
 				return 0;
 			}
 			if (repo_get_merge_bases(the_repository, a, b, &exclude) < 0)
@@ -318,16 +317,16 @@ static int try_difference(const char *arg)
 				show_rev(REVERSED, &commit->object.oid, NULL);
 			}
 		}
-		*dotdot = '.';
+		free(to_free);
 		return 1;
 	}
-	*dotdot = '.';
+	free(to_free);
 	return 0;
 }
 
 static int try_parent_shorthands(const char *arg)
 {
-	char *dotdot;
+	const char *mark;
 	struct object_id oid;
 	struct commit *commit;
 	struct commit_list *parents;
@@ -335,38 +334,39 @@ static int try_parent_shorthands(const char *arg)
 	int include_rev = 0;
 	int include_parents = 0;
 	int exclude_parent = 0;
+	char *to_free;
 
-	if ((dotdot = strstr(arg, "^!"))) {
+	if ((mark = strstr(arg, "^!"))) {
 		include_rev = 1;
-		if (dotdot[2])
+		if (mark[2])
 			return 0;
-	} else if ((dotdot = strstr(arg, "^@"))) {
+	} else if ((mark = strstr(arg, "^@"))) {
 		include_parents = 1;
-		if (dotdot[2])
+		if (mark[2])
 			return 0;
-	} else if ((dotdot = strstr(arg, "^-"))) {
+	} else if ((mark = strstr(arg, "^-"))) {
 		include_rev = 1;
 		exclude_parent = 1;
 
-		if (dotdot[2]) {
+		if (mark[2]) {
 			char *end;
-			exclude_parent = strtoul(dotdot + 2, &end, 10);
+			exclude_parent = strtoul(mark + 2, &end, 10);
 			if (*end != '\0' || !exclude_parent)
 				return 0;
 		}
 	} else
 		return 0;
 
-	*dotdot = 0;
+	arg = to_free = xmemdupz(arg, mark - arg);
 	if (repo_get_oid_committish(the_repository, arg, &oid) ||
 	    !(commit = lookup_commit_reference(the_repository, &oid))) {
-		*dotdot = '^';
+		free(to_free);
 		return 0;
 	}
 
 	if (exclude_parent &&
 	    exclude_parent > commit_list_count(commit->parents)) {
-		*dotdot = '^';
+		free(to_free);
 		return 0;
 	}
 
@@ -387,7 +387,7 @@ static int try_parent_shorthands(const char *arg)
 		free(name);
 	}
 
-	*dotdot = '^';
+	free(to_free);
 	return 1;
 }
 
diff --git a/revision.c b/revision.c
index 31808e3df0..fda405bf65 100644
--- a/revision.c
+++ b/revision.c
@@ -2038,41 +2038,32 @@ static void prepare_show_merge(struct rev_info *revs)
 	free(prune);
 }
 
-static int dotdot_missing(const char *arg, char *dotdot,
+static int dotdot_missing(const char *full_name,
 			  struct rev_info *revs, int symmetric)
 {
 	if (revs->ignore_missing)
 		return 0;
-	/* de-munge so we report the full argument */
-	*dotdot = '.';
 	die(symmetric
 	    ? "Invalid symmetric difference expression %s"
-	    : "Invalid revision range %s", arg);
+	    : "Invalid revision range %s", full_name);
 }
 
-static int handle_dotdot_1(const char *arg, char *dotdot,
+static int handle_dotdot_1(const char *a_name, const char *b_name,
+			   const char *full_name, int symmetric,
 			   struct rev_info *revs, int flags,
 			   int cant_be_filename,
 			   struct object_context *a_oc,
 			   struct object_context *b_oc)
 {
-	const char *a_name, *b_name;
 	struct object_id a_oid, b_oid;
 	struct object *a_obj, *b_obj;
 	unsigned int a_flags, b_flags;
-	int symmetric = 0;
 	unsigned int flags_exclude = flags ^ (UNINTERESTING | BOTTOM);
 	unsigned int oc_flags = GET_OID_COMMITTISH | GET_OID_RECORD_PATH;
 
-	a_name = arg;
 	if (!*a_name)
 		a_name = "HEAD";
 
-	b_name = dotdot + 2;
-	if (*b_name == '.') {
-		symmetric = 1;
-		b_name++;
-	}
 	if (!*b_name)
 		b_name = "HEAD";
 
@@ -2081,15 +2072,13 @@ static int handle_dotdot_1(const char *arg, char *dotdot,
 		return -1;
 
 	if (!cant_be_filename) {
-		*dotdot = '.';
-		verify_non_filename(revs->prefix, arg);
-		*dotdot = '\0';
+		verify_non_filename(revs->prefix, full_name);
 	}
 
 	a_obj = parse_object(revs->repo, &a_oid);
 	b_obj = parse_object(revs->repo, &b_oid);
 	if (!a_obj || !b_obj)
-		return dotdot_missing(arg, dotdot, revs, symmetric);
+		return dotdot_missing(full_name, revs, symmetric);
 
 	if (!symmetric) {
 		/* just A..B */
@@ -2103,7 +2092,7 @@ static int handle_dotdot_1(const char *arg, char *dotdot,
 		a = lookup_commit_reference(revs->repo, &a_obj->oid);
 		b = lookup_commit_reference(revs->repo, &b_obj->oid);
 		if (!a || !b)
-			return dotdot_missing(arg, dotdot, revs, symmetric);
+			return dotdot_missing(full_name, revs, symmetric);
 
 		if (repo_get_merge_bases(the_repository, a, b, &exclude) < 0) {
 			commit_list_free(exclude);
@@ -2132,16 +2121,23 @@ static int handle_dotdot(const char *arg,
 			 int cant_be_filename)
 {
 	struct object_context a_oc = {0}, b_oc = {0};
-	char *dotdot = strstr(arg, "..");
+	const char *dotdot = strstr(arg, "..");
+	char *tmp;
+	int symmetric = 0;
 	int ret;
 
 	if (!dotdot)
 		return -1;
 
-	*dotdot = '\0';
-	ret = handle_dotdot_1(arg, dotdot, revs, flags, cant_be_filename,
-			      &a_oc, &b_oc);
-	*dotdot = '.';
+	tmp = xmemdupz(arg, dotdot - arg);
+	dotdot += 2;
+	if (*dotdot == '.') {
+		symmetric = 1;
+		dotdot++;
+	}
+	ret = handle_dotdot_1(tmp, dotdot, arg, symmetric, revs, flags,
+			      cant_be_filename, &a_oc, &b_oc);
+	free(tmp);
 
 	object_context_release(&a_oc);
 	object_context_release(&b_oc);
@@ -2151,7 +2147,10 @@ static int handle_dotdot(const char *arg,
 static int handle_revision_arg_1(const char *arg_, struct rev_info *revs, int flags, unsigned revarg_opt)
 {
 	struct object_context oc = {0};
-	char *mark;
+	const char *mark;
+	char *arg_minus_at = NULL;
+	char *arg_minus_excl = NULL;
+	char *arg_minus_dash = NULL;
 	struct object *object;
 	struct object_id oid;
 	int local_flags;
@@ -2178,18 +2177,17 @@ static int handle_revision_arg_1(const char *arg_, struct rev_info *revs, int fl
 
 	mark = strstr(arg, "^@");
 	if (mark && !mark[2]) {
-		*mark = 0;
-		if (add_parents_only(revs, arg, flags, 0)) {
+		arg_minus_at = xmemdupz(arg, mark - arg);
+		if (add_parents_only(revs, arg_minus_at, flags, 0)) {
 			ret = 0;
 			goto out;
 		}
-		*mark = '^';
 	}
 	mark = strstr(arg, "^!");
 	if (mark && !mark[2]) {
-		*mark = 0;
-		if (!add_parents_only(revs, arg, flags ^ (UNINTERESTING | BOTTOM), 0))
-			*mark = '^';
+		arg_minus_excl = xmemdupz(arg, mark - arg);
+		if (add_parents_only(revs, arg_minus_excl, flags ^ (UNINTERESTING | BOTTOM), 0))
+			arg = arg_minus_excl;
 	}
 	mark = strstr(arg, "^-");
 	if (mark) {
@@ -2203,9 +2201,9 @@ static int handle_revision_arg_1(const char *arg_, struct rev_info *revs, int fl
 			}
 		}
 
-		*mark = 0;
-		if (!add_parents_only(revs, arg, flags ^ (UNINTERESTING | BOTTOM), exclude_parent))
-			*mark = '^';
+		arg_minus_dash = xmemdupz(arg, mark - arg);
+		if (add_parents_only(revs, arg_minus_dash, flags ^ (UNINTERESTING | BOTTOM), exclude_parent))
+			arg = arg_minus_dash;
 	}
 
 	local_flags = 0;
@@ -2240,6 +2238,9 @@ static int handle_revision_arg_1(const char *arg_, struct rev_info *revs, int fl
 
 out:
 	object_context_release(&oc);
+	free(arg_minus_at);
+	free(arg_minus_excl);
+	free(arg_minus_dash);
 	return ret;
 }