Re: [PATCH] branch: update all per-worktree HEADs when renaming a branch

[Duy Nguyen <pclouds@gmail.com>]

On Tue, Mar 22, 2016 at 12:41 AM, Eric Sunshine <sunshine@sunshineco.com> wrote:
>> diff --git a/worktree.c b/worktree.c
>> @@ -217,3 +217,41 @@ char *find_shared_symref(const char *symref, const char *target)
>> +int update_worktrees_head_symref(const char *oldref, const char *newref)
>> +{
>> +       int error = 0;
>> +       struct strbuf path = STRBUF_INIT;
>> +       struct strbuf origref = STRBUF_INIT;
>> +       int i;
>> +       struct worktree **worktrees = get_worktrees();
>> +
>> +       for (i = 0; worktrees[i]; i++) {
>> +               if (worktrees[i]->is_detached)
>> +                       continue;
>> +
>> +               strbuf_reset(&path);
>> +               strbuf_reset(&origref);
>> +               strbuf_addf(&path, "%s/HEAD", worktrees[i]->git_dir);
>> +
>> +               if (parse_ref(path.buf, &origref, NULL))
>> +                       continue;
>> +
>> +               if (!strcmp(origref.buf, oldref)) {
>> +                       int prefix_len = strlen(absolute_path(get_git_common_dir())) + 1;
>> +                       const char *symref = path.buf + prefix_len;
>> +
>> +                       /* no need to pass logmsg here as HEAD didn't really move */
>> +                       if (create_symref(symref, newref, NULL)) {
>> +                               error = -1;
>> +                               break;
>
> Is aborting upon the first error desired behavior? (Genuine question.)
> Would it make more sense to continue attempting the rename for the
> remaining worktrees (and remember that an error was encountered)?

Since all these HEADs stay at the same (or close) location, if one
fails, I think the rest will fail too. Which leads to a series of
warnings if we continue anyway. A more interesting approach is update
HEADs in a transaction, so we successfully update all or we update
none. But I do not know if ref transactions can be used for HEAD,
especially worktree HEADs. I'm ok with either abort here or continue
anyway, though.
-- 
Duy