On Mon, Feb 27, 2017 at 07:53:02PM -0500, Jeff King wrote:
> On Mon, Feb 27, 2017 at 04:33:36PM -0800, Junio C Hamano wrote:
>
> > A flag to affect the behaviour (as opposed to &flag as a secondary
> > return value, like Peff's patch does) can be made to work. Perhaps
> > a flag that says "keep the input as is if the result is not a local
> > branch name" would pass an input "@" intact and that may be
> > sufficient to allow "git branch -m @" to rename the current branch
> > to "@" (I do not think it is a sensible rename, though ;-). But
> > probably some callers need to keep the original input and compare
> > with the result to see if we expanded anything if we go that route.
> > At that point, I am not sure if there are much differences in the
> > ease of use between the two approaches.
>
> I just went into more detail in my reply to Jacob, but I do think this
> is a workable approach (and fortunately we seem to have banned bare "@"
> as a name, along with anything containing "@{}", so I think we would end
> up rejecting these nonsense names).
>
> I'll see if I can work up a patch. We'll still need to pass the flag
> around through the various functions, but at least it will be a flag and
> not a confusing negated out-parameter.
OK, I have a series which fixes this (diffstat below). When I audited
the other callers of interpret_branch_name() and strbuf_branchname(), it
turned out to be even more complicated. The callers basically fall into
a few buckets:
1. Callers like get_sha1() and merge_name() pass the result to
dwim_ref(), and are prepared to handle anything.
2. Some callers stick "refs/heads/" in front of the result, and
obviously only want local names. Most of git-branch and
git-checkout fall into this boat.
3. "git branch -d" can delete local _or_ remote branches, depending on
the "-r" flag. So the expansion it wants varies, and we need to
handle "just local" or "just remote".
So I converted the "only_branch" flag to an "allowed" bit-field. No
callers actually ask for more than a single type at once, but it was
easy to do it that way. It serves all of the callers, and will easily
adapt for the future (e.g., if "git branch -a -d" were ever allowed).
[1/8]: interpret_branch_name: move docstring to header file
[2/8]: strbuf_branchname: drop return value
[3/8]: strbuf_branchname: add docstring
[4/8]: interpret_branch_name: allow callers to restrict expansions
[5/8]: t3204: test git-branch @-expansion corner cases
[6/8]: branch: restrict @-expansions when deleting
[7/8]: strbuf_check_ref_format(): expand only local branches
[8/8]: checkout: restrict @-expansions when finding branch
builtin/branch.c | 5 +-
builtin/checkout.c | 2 +-
builtin/merge.c | 2 +-
cache.h | 32 ++++++++-
refs.c | 2 +-
revision.c | 2 +-
sha1_name.c | 76 ++++++++++-----------
strbuf.h | 21 +++++-
t/t3204-branch-name-interpretation.sh | 122 ++++++++++++++++++++++++++++++++++
9 files changed, 220 insertions(+), 44 deletions(-)
create mode 100755 t/t3204-branch-name-interpretation.sh
-Peff