sequencer: plug memory leaks for the option values

The sequencer is our attempt to lib-ify cherry-pick. Yet it behaves
like a one-shot command when it reads its configuration: memory is
allocated and released only when the command exits.

This is kind of okay for git-cherry-pick, which *is* a one-shot
command. All the work to make the sequencer its work horse was
done to allow using the functionality as a library function, though,
including proper clean-up after use.

To remedy that, take custody of the option values in question,
allocating and duping literal constants as needed and freeing them
at end.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

3 files changed, 29 insertions, 7 deletions

diff --git a/builtin/revert.c b/builtin/revert.c
index 7365559c97..ba5a88cbfd 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -174,6 +174,10 @@ static void parse_args(int argc, const char **argv, struct replay_opts *opts)
 
 	if (argc > 1)
 		usage_with_options(usage_str, options);
+
+	/* These option values will be free()d */
+	opts->gpg_sign = xstrdup_or_null(opts->gpg_sign);
+	opts->strategy = xstrdup_or_null(opts->strategy);
 }
 
 int cmd_revert(int argc, const char **argv, const char *prefix)
diff --git a/sequencer.c b/sequencer.c
index 8d272fbdca..04c55f2087 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -117,6 +117,13 @@ static int has_conforming_footer(struct strbuf *sb, struct strbuf *sob,
 static void remove_sequencer_state(const struct replay_opts *opts)
 {
 	struct strbuf dir = STRBUF_INIT;
+	int i;
+
+	free(opts->gpg_sign);
+	free(opts->strategy);
+	for (i = 0; i < opts->xopts_nr; i++)
+		free(opts->xopts[i]);
+	free(opts->xopts);
 
 	strbuf_addf(&dir, "%s", get_dir(opts));
 	remove_dir_recursively(&dir, 0);
@@ -280,7 +287,7 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
 	struct merge_options o;
 	struct tree *result, *next_tree, *base_tree, *head_tree;
 	int clean;
-	const char **xopt;
+	char **xopt;
 	static struct lock_file index_lock;
 
 	hold_locked_index(&index_lock, 1);
@@ -583,7 +590,8 @@ static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 
 		commit_list_insert(base, &common);
 		commit_list_insert(next, &remotes);
-		res |= try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
+		res |= try_merge_command(opts->strategy,
+					 opts->xopts_nr, (const char **)opts->xopts,
 					common, sha1_to_hex(head), remotes);
 		free_commit_list(common);
 		free_commit_list(remotes);
@@ -783,6 +791,16 @@ static int read_populate_todo(struct commit_list **todo_list,
 	return 0;
 }
 
+static int git_config_string_dup(char **dest,
+				 const char *var, const char *value)
+{
+	if (!value)
+		return config_error_nonbool(var);
+	free(*dest);
+	*dest = xstrdup(value);
+	return 0;
+}
+
 static int populate_opts_cb(const char *key, const char *value, void *data)
 {
 	struct replay_opts *opts = data;
@@ -803,9 +821,9 @@ static int populate_opts_cb(const char *key, const char *value, void *data)
 	else if (!strcmp(key, "options.mainline"))
 		opts->mainline = git_config_int(key, value);
 	else if (!strcmp(key, "options.strategy"))
-		git_config_string(&opts->strategy, key, value);
+		git_config_string_dup(&opts->strategy, key, value);
 	else if (!strcmp(key, "options.gpg-sign"))
-		git_config_string(&opts->gpg_sign, key, value);
+		git_config_string_dup(&opts->gpg_sign, key, value);
 	else if (!strcmp(key, "options.strategy-option")) {
 		ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
 		opts->xopts[opts->xopts_nr++] = xstrdup(value);
diff --git a/sequencer.h b/sequencer.h
index dd4d33a572..8453669765 100644
--- a/sequencer.h
+++ b/sequencer.h
@@ -34,11 +34,11 @@ struct replay_opts {
 
 	int mainline;
 
-	const char *gpg_sign;
+	char *gpg_sign;
 
 	/* Merge strategy */
-	const char *strategy;
-	const char **xopts;
+	char *strategy;
+	char **xopts;
 	size_t xopts_nr, xopts_alloc;
 
 	/* Only used by REPLAY_NONE */