Merge branch 'nd/shared-index-fix' into maint

Code clean-up.

* nd/shared-index-fix:
  read-cache: don't write index twice if we can't write shared index
  read-cache.c: move tempfile creation/cleanup out of write_shared_index
  read-cache.c: change type of "temp" in write_shared_index()

Author: gitster

read-cache.c

@@ -2472,32 +2472,21 @@ static int clean_shared_index_files(const char *current_hex)
 }
 
 static int write_shared_index(struct index_state *istate,
-			      struct lock_file *lock, unsigned flags)
+			      struct tempfile **temp)
 {
-	struct tempfile *temp;
 	struct split_index *si = istate->split_index;
 	int ret;
 
-	temp = mks_tempfile(git_path("sharedindex_XXXXXX"));
-	if (!temp) {
-		hashclr(si->base_sha1);
-		return do_write_locked_index(istate, lock, flags);
-	}
 	move_cache_to_base_index(istate);
-	ret = do_write_index(si->base, temp, 1);
-	if (ret) {
-		delete_tempfile(&temp);
+	ret = do_write_index(si->base, *temp, 1);
+	if (ret)
 		return ret;
-	}
-	ret = adjust_shared_perm(get_tempfile_path(temp));
+	ret = adjust_shared_perm(get_tempfile_path(*temp));
 	if (ret) {
-		int save_errno = errno;
-		error("cannot fix permission bits on %s", get_tempfile_path(temp));
-		delete_tempfile(&temp);
-		errno = save_errno;
+		error("cannot fix permission bits on %s", get_tempfile_path(*temp));
 		return ret;
 	}
-	ret = rename_tempfile(&temp,
+	ret = rename_tempfile(temp,
 			      git_path("sharedindex.%s", sha1_to_hex(si->base->sha1)));
 	if (!ret) {
 		hashcpy(si->base_sha1, si->base->sha1);
@@ -2565,7 +2554,22 @@ int write_locked_index(struct index_state *istate, struct lock_file *lock,
 	new_shared_index = istate->cache_changed & SPLIT_INDEX_ORDERED;
 
 	if (new_shared_index) {
-		ret = write_shared_index(istate, lock, flags);
+		struct tempfile *temp;
+		int saved_errno;
+
+		temp = mks_tempfile(git_path("sharedindex_XXXXXX"));
+		if (!temp) {
+			hashclr(si->base_sha1);
+			ret = do_write_locked_index(istate, lock, flags);
+			goto out;
+		}
+		ret = write_shared_index(istate, &temp);
+
+		saved_errno = errno;
+		if (is_tempfile_active(temp))
+			delete_tempfile(&temp);
+		errno = saved_errno;
+
 		if (ret)
 			goto out;
 	}

t/t1700-split-index.sh

@@ -401,6 +401,25 @@ done <<\EOF
 0642 -rw-r---w-
 EOF
 
+test_expect_success POSIXPERM,SANITY 'graceful handling when splitting index is not allowed' '
+	test_create_repo ro &&
+	(
+		cd ro &&
+		test_commit initial &&
+		git update-index --split-index &&
+		test -f .git/sharedindex.*
+	) &&
+	cp ro/.git/index new-index &&
+	test_when_finished "chmod u+w ro/.git" &&
+	chmod u-w ro/.git &&
+	GIT_INDEX_FILE="$(pwd)/new-index" git -C ro update-index --split-index &&
+	chmod u+w ro/.git &&
+	rm ro/.git/sharedindex.* &&
+	GIT_INDEX_FILE=new-index git ls-files >actual &&
+	echo initial.t >expected &&
+	test_cmp expected actual
+'
+
 test_expect_success 'writing split index with null sha1 does not write cache tree' '
 	git config core.splitIndex true &&
 	git config splitIndex.maxPercentChange 0 &&