repository.c: free the "path cache" in repo_clear()

The "struct path_cache" added in 102de880d2 (path.c: migrate global
git_path_* to take a repository argument, 2018-05-17) is only used
directly by code in repository.[ch] (but populated in path.[ch]).

Let's move this code to repository.[ch], and stop leaking this memory
when we run repo_clear(). To avoid the cast change it from a "const
char *" to a "char *".

This also removes the "PATH_CACHE_INIT" macro, which has never been
used for anything. For the "struct repository" we already make a hard
assumption that it (and "the_repository") can be identically
initialized by making it a "static" variable, so making use of a
"PATH_CACHE_INIT" somewhere would have been confusing.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

path.h

@@ -169,20 +169,6 @@ void report_linked_checkout_garbage(void);
 		return r->cached_paths.var; \
 	}
 
-struct path_cache {
-	const char *squash_msg;
-	const char *merge_msg;
-	const char *merge_rr;
-	const char *merge_mode;
-	const char *merge_head;
-	const char *merge_autostash;
-	const char *auto_merge;
-	const char *fetch_head;
-	const char *shallow;
-};
-
-#define PATH_CACHE_INIT { 0 }
-
 const char *git_path_squash_msg(struct repository *r);
 const char *git_path_merge_msg(struct repository *r);
 const char *git_path_merge_rr(struct repository *r);

repository.c

@@ -240,6 +240,20 @@ out:
 	return ret;
 }
 
+static void repo_clear_path_cache(struct repo_path_cache *cache)
+{
+	FREE_AND_NULL(cache->squash_msg);
+	FREE_AND_NULL(cache->squash_msg);
+	FREE_AND_NULL(cache->merge_msg);
+	FREE_AND_NULL(cache->merge_rr);
+	FREE_AND_NULL(cache->merge_mode);
+	FREE_AND_NULL(cache->merge_head);
+	FREE_AND_NULL(cache->merge_autostash);
+	FREE_AND_NULL(cache->auto_merge);
+	FREE_AND_NULL(cache->fetch_head);
+	FREE_AND_NULL(cache->shallow);
+}
+
 void repo_clear(struct repository *repo)
 {
 	FREE_AND_NULL(repo->gitdir);
@@ -280,6 +294,8 @@ void repo_clear(struct repository *repo)
 		remote_state_clear(repo->remote_state);
 		FREE_AND_NULL(repo->remote_state);
 	}
+
+	repo_clear_path_cache(&repo->cached_paths);
 }
 
 int repo_read_index(struct repository *repo)

repository.h

@@ -44,6 +44,18 @@ struct repo_settings {
 	int core_multi_pack_index;
 };
 
+struct repo_path_cache {
+	char *squash_msg;
+	char *merge_msg;
+	char *merge_rr;
+	char *merge_mode;
+	char *merge_head;
+	char *merge_autostash;
+	char *auto_merge;
+	char *fetch_head;
+	char *shallow;
+};
+
 struct repository {
 	/* Environment */
 	/*
@@ -82,7 +94,7 @@ struct repository {
 	/*
 	 * Contains path to often used file names.
 	 */
-	struct path_cache cached_paths;
+	struct repo_path_cache cached_paths;
 
 	/*
 	 * Path to the repository's graft file.