sparse-checkout: create leading directories

The 'git init' command creates the ".git/info" directory and fills it
with some default files. However, 'git worktree add' does not create
the info directory for that worktree. This causes a problem when running
"git sparse-checkout init" inside a worktree. While care was taken to
allow the sparse-checkout config to be specific to a worktree, this
initialization was untested.

Safely create the leading directories for the sparse-checkout file. This
is the safest thing to do even without worktrees, as a user could delete
their ".git/info" directory and expect Git to recover safely.

Signed-off-by: Derrick Stolee <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: derrickstolee

builtin/sparse-checkout.c

@@ -199,6 +199,10 @@ static int write_patterns_and_update(struct pattern_list *pl)
 	int result;
 
 	sparse_filename = get_sparse_checkout_filename();
+
+	if (safe_create_leading_directories(sparse_filename))
+		die(_("failed to create directory for sparse-checkout file"));
+
 	fd = hold_lock_file_for_update(&lk, sparse_filename,
 				      LOCK_DIE_ON_ERROR);
 

t/t1091-sparse-checkout-builtin.sh

@@ -295,4 +295,14 @@ test_expect_success 'interaction with submodules' '
 	check_files super/modules/child a deep folder1 folder2
 '
 
+test_expect_success 'different sparse-checkouts with worktrees' '
+	git -C repo worktree add --detach ../worktree &&
+	check_files worktree "a deep folder1 folder2" &&
+	git -C worktree sparse-checkout init --cone &&
+	git -C repo sparse-checkout set folder1 &&
+	git -C worktree sparse-checkout set deep/deeper1 &&
+	check_files repo a folder1 &&
+	check_files worktree a deep
+'
+
 test_done