Merge branch 'jt/unparse-commit-upon-graft-change'

Updating the graft information invalidates the list of parents of
in-core commit objects that used to be in the graft file.

* jt/unparse-commit-upon-graft-change:
  commit,shallow: unparse commits if grafts changed

commit.c

@@ -120,6 +120,17 @@ int commit_graft_pos(struct repository *r, const struct object_id *oid)
 		       commit_graft_oid_access);
 }
 
+static void unparse_commit(struct repository *r, const struct object_id *oid)
+{
+	struct commit *c = lookup_commit(r, oid);
+
+	if (!c->object.parsed)
+		return;
+	free_commit_list(c->parents);
+	c->parents = NULL;
+	c->object.parsed = 0;
+}
+
 int register_commit_graft(struct repository *r, struct commit_graft *graft,
 			  int ignore_dups)
 {
@@ -145,6 +156,7 @@ int register_commit_graft(struct repository *r, struct commit_graft *graft,
 			(r->parsed_objects->grafts_nr - pos - 1) *
 			sizeof(*r->parsed_objects->grafts));
 	r->parsed_objects->grafts[pos] = graft;
+	unparse_commit(r, &graft->oid);
 	return 0;
 }
 
@@ -253,8 +265,10 @@ void reset_commit_grafts(struct repository *r)
 {
 	int i;
 
-	for (i = 0; i < r->parsed_objects->grafts_nr; i++)
+	for (i = 0; i < r->parsed_objects->grafts_nr; i++) {
+		unparse_commit(r, &r->parsed_objects->grafts[i]->oid);
 		free(r->parsed_objects->grafts[i]);
+	}
 	r->parsed_objects->grafts_nr = 0;
 	r->parsed_objects->commit_graft_prepared = 0;
 }

shallow.c

@@ -97,6 +97,13 @@ int commit_shallow_file(struct repository *r, struct shallow_lock *lk)
 {
 	int res = commit_lock_file(&lk->lock);
 	reset_repository_shallow(r);
+
+	/*
+	 * Update in-memory data structures with the new shallow information,
+	 * including unparsing all commits that now have grafts.
+	 */
+	is_repository_shallow(r);
+
 	return res;
 }
 

t/t5537-fetch-shallow.sh

@@ -164,12 +164,24 @@ test_expect_success 'fetch --update-shallow' '
 test_expect_success 'fetch --update-shallow into a repo with submodules' '
 	git init a-submodule &&
 	test_commit -C a-submodule foo &&
+
+	test_when_finished "rm -rf repo-with-sub" &&
 	git init repo-with-sub &&
 	git -C repo-with-sub submodule add ../a-submodule a-submodule &&
 	git -C repo-with-sub commit -m "added submodule" &&
 	git -C repo-with-sub fetch --update-shallow ../shallow/.git refs/heads/*:refs/remotes/shallow/*
 '
 
+test_expect_success 'fetch --update-shallow a commit that is also a shallow point into a repo with submodules' '
+	test_when_finished "rm -rf repo-with-sub" &&
+	git init repo-with-sub &&
+	git -C repo-with-sub submodule add ../a-submodule a-submodule &&
+	git -C repo-with-sub commit -m "added submodule" &&
+
+	SHALLOW=$(cat shallow/.git/shallow) &&
+	git -C repo-with-sub fetch --update-shallow ../shallow/.git "$SHALLOW":refs/heads/a-shallow
+'
+
 test_expect_success 'fetch --update-shallow (with fetch.writeCommitGraph)' '
 	(
 	cd shallow &&