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[PATCH v4 7/9] submodule: fetch in submodules git directory instead of in worktree

From
Stefan Beller <sbeller@google.com>
Date
Sep 25, 2018, 19:47 UTC
Message-ID
<20180925194755.105578-8-sbeller@google.com>
In-Reply-To
<20180925194755.105578-1-sbeller@google.com>

This patch started as a refactoring to make 'get_next_submodule' more readable, but upon doing so, I realized that "git fetch" of the submodule actually doesn't need to be run in the submodules worktree. So let's run it in its git dir instead.

That should pave the way towards fetching submodules that are currently not checked out.

This patch leaks the cp->dir in get_next_submodule, as any further callback in run_processes_parallel doesn't have access to the child process any more. In an early iteration of this patch, the function get_submodule_repo_for directly returned the string containing the git directory, which would be a better design choice for this patch.

However the next patch both fixes the memory leak of cp->dir and also has a use case for using the full repository handle of the submodule, so it makes sense to introduce the get_submodule_repo_for here already.

Signed-off-by: Stefan Beller <sbeller@google.com>
---
 submodule.c                 | 51 +++++++++++++++++++++++++++----------
 t/t5526-fetch-submodules.sh |  7 ++++-
 2 files changed, 44 insertions(+), 14 deletions(-)
diff --git a/submodule.c b/submodule.c
index dd478ed70bf..3f791f22771 100644
--- a/submodule.c
+++ b/submodule.c
@@ -481,6 +481,12 @@ void prepare_submodule_repo_env(struct argv_array *out)
 			 DEFAULT_GIT_DIR_ENVIRONMENT);
 }
 
+static void prepare_submodule_repo_env_in_gitdir(struct argv_array *out)
+{
+	prepare_submodule_repo_env_no_git_dir(out);
+	argv_array_pushf(out, "%s=.", GIT_DIR_ENVIRONMENT);
+}
+
 /* Helper function to display the submodule header line prior to the full
  * summary output. If it can locate the submodule objects directory it will
  * attempt to lookup both the left and right commits and put them into the
@@ -1227,6 +1233,29 @@ static int get_fetch_recurse_config(const struct submodule *submodule,
 	return spf->default_option;
 }
 
+static struct repository *get_submodule_repo_for(struct repository *r,
+						 const struct submodule *sub)
+{
+	struct repository *ret = xmalloc(sizeof(*ret));
+
+	if (repo_submodule_init(ret, r, sub)) {
+		/*
+		 * No entry in .gitmodules? Technically not a submodule,
+		 * but historically we supported repositories that happen to be
+		 * in-place where a gitlink is. Keep supporting them.
+		 */
+		struct strbuf gitdir = STRBUF_INIT;
+		strbuf_repo_worktree_path(&gitdir, r, "%s/.git", sub->path);
+		if (repo_init(ret, gitdir.buf, NULL)) {
+			strbuf_release(&gitdir);
+			return NULL;
+		}
+		strbuf_release(&gitdir);
+	}
+
+	return ret;
+}
+
 static int get_next_submodule(struct child_process *cp,
 			      struct strbuf *err, void *data, void **task_cb)
 {
@@ -1234,12 +1263,11 @@ static int get_next_submodule(struct child_process *cp,
 	struct submodule_parallel_fetch *spf = data;
 
 	for (; spf->count < spf->r->index->cache_nr; spf->count++) {
-		struct strbuf submodule_path = STRBUF_INIT;
-		struct strbuf submodule_git_dir = STRBUF_INIT;
 		struct strbuf submodule_prefix = STRBUF_INIT;
 		const struct cache_entry *ce = spf->r->index->cache[spf->count];
-		const char *git_dir, *default_argv;
+		const char *default_argv;
 		const struct submodule *submodule;
+		struct repository *repo;
 		struct submodule default_submodule = SUBMODULE_INIT;
 
 		if (!S_ISGITLINK(ce->ce_mode))
@@ -1274,16 +1302,12 @@ static int get_next_submodule(struct child_process *cp,
 			continue;
 		}
 
-		strbuf_repo_worktree_path(&submodule_path, spf->r, "%s", ce->name);
-		strbuf_addf(&submodule_git_dir, "%s/.git", submodule_path.buf);
 		strbuf_addf(&submodule_prefix, "%s%s/", spf->prefix, ce->name);
-		git_dir = read_gitfile(submodule_git_dir.buf);
-		if (!git_dir)
-			git_dir = submodule_git_dir.buf;
-		if (is_directory(git_dir)) {
+		repo = get_submodule_repo_for(spf->r, submodule);
+		if (repo) {
 			child_process_init(cp);
-			cp->dir = strbuf_detach(&submodule_path, NULL);
-			prepare_submodule_repo_env(&cp->env_array);
+			prepare_submodule_repo_env_in_gitdir(&cp->env_array);
+			cp->dir = xstrdup(repo->gitdir);
 			cp->git_cmd = 1;
 			if (!spf->quiet)
 				strbuf_addf(err, "Fetching submodule %s%s\n",
@@ -1293,10 +1317,11 @@ static int get_next_submodule(struct child_process *cp,
 			argv_array_push(&cp->args, default_argv);
 			argv_array_push(&cp->args, "--submodule-prefix");
 			argv_array_push(&cp->args, submodule_prefix.buf);
+
+			repo_clear(repo);
+			free(repo);
 			ret = 1;
 		}
-		strbuf_release(&submodule_path);
-		strbuf_release(&submodule_git_dir);
 		strbuf_release(&submodule_prefix);
 		if (ret) {
 			spf->count++;
diff --git a/t/t5526-fetch-submodules.sh b/t/t5526-fetch-submodules.sh
index 6c2f9b2ba26..42692219a1a 100755
--- a/t/t5526-fetch-submodules.sh
+++ b/t/t5526-fetch-submodules.sh
@@ -566,7 +566,12 @@ test_expect_success 'fetching submodule into a broken repository' '
 
 	test_must_fail git -C dst status &&
 	test_must_fail git -C dst diff &&
-	test_must_fail git -C dst fetch --recurse-submodules
+
+	# git-fetch cannot find the git directory of the submodule,
+	# so it will do nothing, successfully, as it cannot distinguish between
+	# this broken submodule and a submodule that was just set active but
+	# not cloned yet
+	git -C dst fetch --recurse-submodules
 '
 
 test_expect_success "fetch new commits when submodule got renamed" '
-- 
2.19.0.605.g01d371f741-goog
Previous: Stefan BellerNext: Stefan Beller
Message 12 of 14 in “fetch: make sure submodule oids are fetched”
  1. 0/9 fetch: make sure submodule oids are fetchedStefan Beller, Sep 25, 2018
  2. 1/9 sha1-array: provide oid_array_filterStefan Beller, Sep 25, 2018
  3. Junio C HamanoSep 26, 2018
  4. 2/9 submodule.c: fix indentationStefan Beller, Sep 25, 2018
  5. Junio C HamanoSep 26, 2018
  6. 3/9 submodule.c: sort changed_submodule_names before searching itStefan Beller, Sep 25, 2018
  7. Junio C HamanoSep 26, 2018
  8. 4/9 submodule: move global changed_submodule_names into fetch submodule structStefan Beller, Sep 25, 2018
  9. Junio C HamanoSep 26, 2018
  10. 5/9 submodule.c: do not copy around submodule listStefan Beller, Sep 25, 2018
  11. 6/9 repository: repo_submodule_init to take a submodule structStefan Beller, Sep 25, 2018
  12. 7/9 submodule: fetch in submodules git directory instead of in worktreeStefan Beller, Sep 25, 2018
  13. 8/9 fetch: retry fetching submodules if needed objects were not fetchedStefan Beller, Sep 25, 2018
  14. 9/9 builtin/fetch: check for submodule updates for non branch fetchesStefan Beller, Sep 25, 2018

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