submodule: fix leaking fetch tasks

When done with a fetch task used for parallel fetches of submodules, we
need to both call `fetch_task_release()` to release the task's contents
and `free()` to release the task itself. Most sites do this already, but
some only call `fetch_task_release()` and thus leak memory.

While we could trivially fix this by adding the two missing calls to
free(3P), the result would be that we always call both functions. Let's
thus refactor the code such that `fetch_task_release()` also frees the
structure itself. Rename it to `fetch_task_free()` accordingly.

Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: pks-t

submodule.c

@@ -1496,7 +1496,7 @@ static const struct submodule *get_non_gitmodules_submodule(const char *path)
 	return (const struct submodule *) ret;
 }
 
-static void fetch_task_release(struct fetch_task *p)
+static void fetch_task_free(struct fetch_task *p)
 {
 	if (p->free_sub)
 		free((void*)p->sub);
@@ -1508,6 +1508,7 @@ static void fetch_task_release(struct fetch_task *p)
 	FREE_AND_NULL(p->repo);
 
 	strvec_clear(&p->git_args);
+	free(p);
 }
 
 static struct repository *get_submodule_repo_for(struct repository *r,
@@ -1576,8 +1577,7 @@ static struct fetch_task *fetch_task_create(struct submodule_parallel_fetch *spf
 	return task;
 
  cleanup:
-	fetch_task_release(task);
-	free(task);
+	fetch_task_free(task);
 	return NULL;
 }
 
@@ -1607,8 +1607,7 @@ get_fetch_task_from_index(struct submodule_parallel_fetch *spf,
 		} else {
 			struct strbuf empty_submodule_path = STRBUF_INIT;
 
-			fetch_task_release(task);
-			free(task);
+			fetch_task_free(task);
 
 			/*
 			 * An empty directory is normal,
@@ -1654,8 +1653,7 @@ get_fetch_task_from_changed(struct submodule_parallel_fetch *spf,
 				    cs_data->path,
 				    repo_find_unique_abbrev(the_repository, cs_data->super_oid, DEFAULT_ABBREV));
 
-			fetch_task_release(task);
-			free(task);
+			fetch_task_free(task);
 			continue;
 		}
 
@@ -1763,7 +1761,7 @@ static int fetch_start_failure(struct strbuf *err UNUSED,
 
 	spf->result = 1;
 
-	fetch_task_release(task);
+	fetch_task_free(task);
 	return 0;
 }
 
@@ -1828,8 +1826,7 @@ static int fetch_finish(int retvalue, struct strbuf *err UNUSED,
 	}
 
 out:
-	fetch_task_release(task);
-
+	fetch_task_free(task);
 	return 0;
 }