worktree: invoke post-checkout hook (unless --no-checkout)

git-clone and git-checkout both invoke the post-checkout hook following
a successful checkout, yet git-worktree neglects to do so even though it
too "checks out" the worktree. Fix this oversight.

Implementation note: The newly-created worktree may reference a branch
or be detached. In the latter case, a commit lookup is performed, though
the result is used only in a boolean sense to (a) determine if the
commit actually exists, and (b) assign either the branch name or commit
ID to HEAD. Since the post-commit hook needs to know the ID of the
checked-out commit, the lookup now needs to be done in all cases, rather
than only when detached. Consequently, a new boolean is needed to handle
(b) since the lookup result itself can no longer perform that role.

Reported-by: Matthew K Gumbel <matthew.k.gumbel@intel.com>
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/t/t2025-worktree-add.sh b/t/t2025-worktree-add.sh
index b5c47ac..d6fb062 100755
--- a/t/t2025-worktree-add.sh
+++ b/t/t2025-worktree-add.sh
@@ -314,4 +314,33 @@ test_expect_success 'rename a branch under bisect not allowed' '
 	test_must_fail git branch -M under-bisect bisect-with-new-name
 '
 
+post_checkout_hook () {
+	test_when_finished "rm -f .git/hooks/post-checkout" &&
+	mkdir -p .git/hooks &&
+	write_script .git/hooks/post-checkout <<-\EOF
+	echo $* >hook.actual
+	EOF
+}
+
+test_expect_success '"add" invokes post-checkout hook (branch)' '
+	post_checkout_hook &&
+	printf "%s %s 1\n" $_z40 $(git rev-parse HEAD) >hook.expect &&
+	git worktree add gumby &&
+	test_cmp hook.expect hook.actual
+'
+
+test_expect_success '"add" invokes post-checkout hook (detached)' '
+	post_checkout_hook &&
+	printf "%s %s 1\n" $_z40 $(git rev-parse HEAD) >hook.expect &&
+	git worktree add --detach grumpy &&
+	test_cmp hook.expect hook.actual
+'
+
+test_expect_success '"add --no-checkout" suppresses post-checkout hook' '
+	post_checkout_hook &&
+	rm -f hook.actual &&
+	git worktree add --no-checkout gloopy &&
+	test_path_is_missing hook.actual
+'
+
 test_done