[PATCH v2 1/2] dir: consider worktree config in path recursion

[Goss Geppert <gg.oss.dev@gmail.com>]

Since 8d92fb2927 (dir: replace exponential algorithm with a linear one,
2020-04-01) the following no longer works:

    1) Initialize a repository.
    2) Set the `core.worktree` location to a parent directory of the
       default worktree.
    3) Add a file located in the default worktree location to the index
       (i.e. anywhere in the immediate parent directory of the gitdir).

This commit adds a check to determine whether a nested repository that
is encountered in recursing a path is actually `the_repository`.  If so,
simply treat the directory as if it doesn't contain a nested repository.

Prior to this commit, the `add` operation was silently ignored.

Signed-off-by: Goss Geppert <ggossdev@gmail.com>
---
 dir.c                          | 22 +++++++++
 t/t2205-add-worktree-config.sh | 89 ++++++++++++++++++++++++++++++++++
 2 files changed, 111 insertions(+)
 create mode 100755 t/t2205-add-worktree-config.sh

diff --git a/dir.c b/dir.c
index f2b0f24210..a1886e61a3 100644
--- a/dir.c
+++ b/dir.c
@@ -1893,9 +1893,31 @@ static enum path_treatment treat_directory(struct dir_struct *dir,
 
 	if ((dir->flags & DIR_SKIP_NESTED_GIT) ||
 		!(dir->flags & DIR_NO_GITLINKS)) {
+		/*
+		 * Determine if `dirname` is a nested repo by confirming that:
+		 * 1) we are in a nonbare repository, and
+		 * 2) `dirname` is not an immediate parent of `the_repository->gitdir`,
+		 *    which could occur if the `worktree` location was manually
+		 *    configured by the user; see t2205 testcases 1a-1d for examples
+		 *    where this matters
+		 */
 		struct strbuf sb = STRBUF_INIT;
 		strbuf_addstr(&sb, dirname);
 		nested_repo = is_nonbare_repository_dir(&sb);
+
+		if (nested_repo) {
+			char *real_dirname, *real_gitdir;
+			strbuf_reset(&sb);
+			strbuf_addstr(&sb, dirname);
+			strbuf_complete(&sb, '/');
+			strbuf_addstr(&sb, ".git");
+			real_dirname = real_pathdup(sb.buf, 0);
+			real_gitdir = real_pathdup(the_repository->gitdir, 0);
+
+			nested_repo = !!strcmp(real_dirname, real_gitdir);
+			free(real_gitdir);
+			free(real_dirname);
+		}
 		strbuf_release(&sb);
 	}
 	if (nested_repo) {
diff --git a/t/t2205-add-worktree-config.sh b/t/t2205-add-worktree-config.sh
new file mode 100755
index 0000000000..ca70cf3fe2
--- /dev/null
+++ b/t/t2205-add-worktree-config.sh
@@ -0,0 +1,89 @@
+#!/bin/sh
+
+test_description='directory traversal respects worktree config
+
+This test configures the repository`s worktree to be two levels above the
+`.git` directory and checks whether we are able to add to the index those files
+that are in either (1) the manually configured worktree directory or (2) the
+standard worktree location with respect to the `.git` directory (i.e. ensuring
+that the encountered `.git` directory is not treated as belonging to a foreign
+nested repository)'
+
+. ./test-lib.sh
+
+test_expect_success '1a: setup' '
+	test_create_repo test1 &&
+	git --git-dir="test1/.git" config core.worktree "$(pwd)" &&
+
+	mkdir -p outside-tracked outside-untracked &&
+	mkdir -p test1/inside-tracked test1/inside-untracked &&
+	>file-tracked &&
+	>file-untracked &&
+	>outside-tracked/file &&
+	>outside-untracked/file &&
+	>test1/file-tracked &&
+	>test1/file-untracked &&
+	>test1/inside-tracked/file &&
+	>test1/inside-untracked/file &&
+
+	cat >expect-tracked-unsorted <<-EOF &&
+	../file-tracked
+	../outside-tracked/file
+	file-tracked
+	inside-tracked/file
+	EOF
+
+	cat >expect-untracked-unsorted <<-EOF &&
+	../file-untracked
+	../outside-untracked/file
+	file-untracked
+	inside-untracked/file
+	EOF
+
+	cat expect-tracked-unsorted expect-untracked-unsorted >expect-all-unsorted &&
+
+	cat >.gitignore <<-EOF
+	.gitignore
+	actual-*
+	expect-*
+	EOF
+'
+
+test_expect_success '1b: pre-add all' '
+	local parent_dir="$(pwd)" &&
+	(
+		cd test1 &&
+		git ls-files -o --exclude-standard "$parent_dir" >../actual-all-unsorted
+	) &&
+	sort actual-all-unsorted >actual-all &&
+	sort expect-all-unsorted >expect-all &&
+	test_cmp expect-all actual-all
+'
+
+test_expect_success '1c: post-add tracked' '
+	local parent_dir="$(pwd)" &&
+	(
+		cd test1 &&
+		git add file-tracked &&
+		git add inside-tracked &&
+		git add ../outside-tracked &&
+		git add "$parent_dir/file-tracked" &&
+		git ls-files "$parent_dir" >../actual-tracked-unsorted
+	) &&
+	sort actual-tracked-unsorted >actual-tracked &&
+	sort expect-tracked-unsorted >expect-tracked &&
+	test_cmp expect-tracked actual-tracked
+'
+
+test_expect_success '1d: post-add untracked' '
+	local parent_dir="$(pwd)" &&
+	(
+		cd test1 &&
+		git ls-files -o --exclude-standard "$parent_dir" >../actual-untracked-unsorted
+	) &&
+	sort actual-untracked-unsorted >actual-untracked &&
+	sort expect-untracked-unsorted >expect-untracked &&
+	test_cmp expect-untracked actual-untracked
+'
+
+test_done
-- 
2.36.0