"git checkout -B <branch> [<start-point>]", being a "forced" version
of "-b", switches to the <branch>, after optionally resetting its
tip to the <start-point>, even if the <branch> is in use in another
worktree, which is somewhat unexpected.
Protect the <branch> using the same logic that forbids "git checkout
<branch>" from touching a branch that is in use elsewhere.
This is a breaking change that may deserve backward compatibliity
warning in the Release Notes. The "--ignore-other-worktrees" option
can be used as an escape hatch if the finger memory of existing
users depend on the current behaviour of "-B".
Reported-by: Willem Verstraeten <willem.verstraeten@xxxxxxxxx>
Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx>
---
* The documentation might also need updates, but I didn't look at.
builtin/checkout.c | 7 +++++++
t/t2060-switch.sh | 2 ++
t/t2400-worktree-add.sh | 8 ++++++++
3 files changed, 17 insertions(+)
diff --git a/builtin/checkout.c b/builtin/checkout.c
index b4ab972c5a..8a8ad23e98 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -1600,6 +1600,13 @@ static int checkout_branch(struct checkout_opts *opts,
if (new_branch_info->path && !opts->force_detach && !opts->new_branch)
die_if_switching_to_a_branch_in_use(opts, new_branch_info->path);
+ /* "git checkout -B <branch>" */
+ if (opts->new_branch_force) {
+ char *full_ref = xstrfmt("refs/heads/%s", opts->new_branch);
+ die_if_switching_to_a_branch_in_use(opts, full_ref);
+ free(full_ref);
+ }
+
if (!new_branch_info->commit && opts->new_branch) {
struct object_id rev;
int flag;
diff --git a/t/t2060-switch.sh b/t/t2060-switch.sh
index e247a4735b..c91c4db936 100755
--- a/t/t2060-switch.sh
+++ b/t/t2060-switch.sh
@@ -170,8 +170,10 @@ test_expect_success 'switch back when temporarily detached and checked out elsew
# we test in both worktrees to ensure that works
# as expected with "first" and "next" worktrees
test_must_fail git -C wt1 switch shared &&
+ test_must_fail git -C wt1 switch -C shared &&
git -C wt1 switch --ignore-other-worktrees shared &&
test_must_fail git -C wt2 switch shared &&
+ test_must_fail git -C wt2 switch -C shared &&
git -C wt2 switch --ignore-other-worktrees shared
'
diff --git a/t/t2400-worktree-add.sh b/t/t2400-worktree-add.sh
index df4aff7825..bbcb2d3419 100755
--- a/t/t2400-worktree-add.sh
+++ b/t/t2400-worktree-add.sh
@@ -126,6 +126,14 @@ test_expect_success 'die the same branch is already checked out' '
)
'
+test_expect_success 'refuse to reset a branch in use elsewhere' '
+ (
+ cd here &&
+ test_must_fail git checkout -B newmain 2>actual &&
+ grep "already used by worktree at" actual
+ )
+'
+
test_expect_success SYMLINKS 'die the same branch is already checked out (symlink)' '
head=$(git -C there rev-parse --git-path HEAD) &&
ref=$(git -C there symbolic-ref HEAD) &&
--
2.43.0
