Re: git checkout -B <branch> lets you checkout a branch that is already checked out in another worktree Inbox
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Nov 23, 2023, 05:58 UTC
- Message-ID
- <xmqqv89tau3r.fsf@gitster.g>
- In-Reply-To
- <xmqqjzq9cl70.fsf@gitster.g>
Junio C Hamano <gitster@pobox.com> writes:
Show 11 quoted lines
> I guess we could change the behaviour so that > > git checkout -B <branch> [<start-point>] > > fails when <branch> is an existing branch that is in use in another > worktree, and allow "-f" to be used to override the safety, i.e., > > git checkout -f -B <branch> [<start-point>] > > would allow the <branch> to be repointed to <start-point> (or HEAD) > even when it is used elsewhere.
It turns out that for some reason "-f" is not how we decided to override this one---there is "--ignore-other-worktrees" option.
I'll attach the first step (preparatory refactoring) to this message below, and follow it up with the second step to implement and test the change.
--- >8 --- From: Junio C Hamano <gitster@pobox.com> Date: Thu, 23 Nov 2023 14:11:41 +0900 Subject: [PATCH 1/2] checkout: refactor die_if_checked_out() caller
There is a bit dense logic to make a call to "die_if_checked_out()" while trying to check out a branch. Extract it into a helper function and give it a bit of comment to describe what is going on.
The most important part of the refactoring is the separation of the guarding logic before making the call to die_if_checked_out() into the caller specific part (e.g., the logic that decides that the caller is trying to check out an existing branch) and the bypass due to the "--ignore-other-worktrees" option. The latter will be common no matter how the current or future callers decides they need this protection.
Signed-off-by: Junio C Hamano <gitster@pobox.com> --- builtin/checkout.c | 32 +++++++++++++++++++++++--------- 1 file changed, 23 insertions(+), 9 deletions(-)
diff --git a/builtin/checkout.c b/builtin/checkout.c index f02434bc15..b4ab972c5a 100644 --- a/builtin/checkout.c +++ b/builtin/checkout.c @@ -1516,6 +1516,26 @@ static void die_if_some_operation_in_progress(void) wt_status_state_free_buffers(&state); } +/* + * die if attempting to checkout an existing branch that is in use + * in another worktree, unless ignore-other-wortrees option is given. + * The check is bypassed when the branch is already the current one, + * as it will not make things any worse. + */ +static void die_if_switching_to_a_branch_in_use(struct checkout_opts *opts, + const char *full_ref) +{ + int flags; + char *head_ref; + + if (opts->ignore_other_worktrees) + return; + head_ref = resolve_refdup("HEAD", 0, NULL, &flags); + if (head_ref && (!(flags & REF_ISSYMREF) || strcmp(head_ref, full_ref))) + die_if_checked_out(full_ref, 1); + free(head_ref); +} + static int checkout_branch(struct checkout_opts *opts, struct branch_info *new_branch_info) { @@ -1576,15 +1596,9 @@ static int checkout_branch(struct checkout_opts *opts, if (!opts->can_switch_when_in_progress) die_if_some_operation_in_progress(); - if (new_branch_info->path && !opts->force_detach && !opts->new_branch && - !opts->ignore_other_worktrees) { - int flag; - char *head_ref = resolve_refdup("HEAD", 0, NULL, &flag); - if (head_ref && - (!(flag & REF_ISSYMREF) || strcmp(head_ref, new_branch_info->path))) - die_if_checked_out(new_branch_info->path, 1); - free(head_ref); - } + /* "git checkout <branch>" */ + if (new_branch_info->path && !opts->force_detach && !opts->new_branch) + die_if_switching_to_a_branch_in_use(opts, new_branch_info->path); if (!new_branch_info->commit && opts->new_branch) { struct object_id rev;
-- 2.43.0