Re: [PATCH v3] branch -d: refuse deleting a branch which is currently checked out

> When a branch is checked out by current working tree, deleting the
> branch is forbidden. However when the branch is checked out only by
> other working trees, deleting incorrectly succeeds.
> Use find_shared_symref() to check if the branch is in use, not just
> comparing with the current working tree's HEAD.
>
> Helped-by: Eric Sunshine <sunshine@sunshineco.com>
> Signed-off-by: Kazuki Yamaguchi <k@rhe.jp>
> ---
> Changes from v2:
> - Amended commit message
> - Dropped "which is" from error message

> The previous versions of the patch are:
> - [v1] http://thread.gmane.org/gmane.comp.version-control.git/289413/focus=289932
> - [v2] http://thread.gmane.org/gmane.comp.version-control.git/289413/focus=290027
>
>  builtin/branch.c  | 22 ++++++++++++++--------
>  t/t3200-branch.sh |  6 ++++++
>  2 files changed, 20 insertions(+), 8 deletions(-)
>
> diff --git a/builtin/branch.c b/builtin/branch.c
> index 7b45b6bd6b80..8885d9f8e2cd 100644
> --- a/builtin/branch.c
> +++ b/builtin/branch.c
> @@ -20,6 +20,7 @@
>  #include "utf8.h"
>  #include "wt-status.h"
>  #include "ref-filter.h"
> +#include "worktree.h"
>
>  static const char * const builtin_branch_usage[] = {
>         N_("git branch [<options>] [-r | -a] [--merged | --no-merged]"),
> @@ -215,16 +216,21 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
>                 int flags = 0;
>
>                 strbuf_branchname(&bname, argv[i]);
> -               if (kinds == FILTER_REFS_BRANCHES && !strcmp(head, bname.buf)) {
> -                       error(_("Cannot delete the branch '%s' "
> -                             "which you are currently on."), bname.buf);
> -                       ret = 1;
> -                       continue;
> -               }
> -
>                 free(name);
> -
>                 name = mkpathdup(fmt, bname.buf);
> +
> +               if (kinds == FILTER_REFS_BRANCHES) {
> +                       char *worktree = find_shared_symref("HEAD", name);
> +                       if (worktree) {
> +                               error(_("Cannot delete branch '%s' "
> +                                       "checked out at '%s'"),
> +                                     bname.buf, worktree);
> +                               free(worktree);
> +                               ret = 1;
> +                               continue;
> +                       }
> +               }
> +
>                 target = resolve_ref_unsafe(name,
>                                             RESOLVE_REF_READING
>                                             | RESOLVE_REF_NO_RECURSE
> diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
> index a89724849065..508007fd3772 100755
> --- a/t/t3200-branch.sh
> +++ b/t/t3200-branch.sh
> @@ -403,6 +403,12 @@ test_expect_success 'test deleting branch without config' '
>         test_i18ncmp expect actual
>  '
>
> +test_expect_success 'deleting currently checked out branch fails' '
> +       git worktree add -b my7 my7 &&
> +       test_must_fail git -C my7 branch -d my7 &&
> +       test_must_fail git branch -d my7
> +'
> +
>  test_expect_success 'test --track without .fetch entries' '
>         git branch --track my8 &&
>         test "$(git config branch.my8.remote)" &&
> --
> 2.8.0.rc4.17.g02aa164.dirty