RFR: 92: GitRepository::currentBranch fails when on a detached HEAD

[Erik Helin]

On Fri, 29 Nov 2019 11:30:04 GMT, Robin Westberg <rwestberg at openjdk.org> wrote:

> On Fri, 29 Nov 2019 11:27:22 GMT, Robin Westberg <rwestberg at openjdk.org> wrote:
> 
>> On Thu, 28 Nov 2019 15:10:50 GMT, Erik Helin <ehelin at openjdk.org> wrote:
>> 
>>> Hi all,
>>> 
>>> please review this pull request that makes `git webrev` work when the repository is in a "detached HEAD" state (i.e. there is no active branch). The main part of the change is making `ReadOnlyRepository::currentBranch` return `Optional<Branch>` instead of `Branch`.
>>> 
>>> Thanks,
>>> Erik
>>> 
>>> ## Testing
>>> - [x] `make test` on Linux x64
>>> - [x] Manually running `git webrev` on a repository with a detached HEAD
>>> 
>>> ----------------
>>> 
>>> Commits:
>>>  - 3dc4fea9: 92: GitRepository::currentBranch fails when on a detached HEAD
>>> 
>>> Changes: https://git.openjdk.java.net/skara/pull/278/files
>>>  Webrev: https://webrevs.openjdk.java.net/skara/278/webrev.00
>>>   Issue: https://bugs.openjdk.java.net/browse/SKARA-92
>>>   Stats: 40 lines in 8 files changed: 16 ins; 2 del; 22 mod
>>>   Patch: https://git.openjdk.java.net/skara/pull/278.diff
>>>   Fetch: git fetch https://git.openjdk.java.net/skara pull/278/head:pull/278
>> 
>> vcs/src/main/java/org/openjdk/skara/vcs/hg/HgRepository.java line 603:
>> 
>>> 602:         var current = currentBranch().orElseThrow(() ->
>>> 603:                 new IOException("No current branch to rebase upon")
>>> 604:         );
>> 
>> Should this mention the detached head then as well perhaps?
> 
> Scratch that, guess this is hg :)

Yes, this is in `HgRepository`, so a "detached HEAD" is not possible. I actually don't think `currentBranch` _can_ fail for `HgRepository`, since the current branch is part of the commit metadata in Mercurial (not just a ref as in git). I added a message anyhow to distinguish this scenario.

PR: https://git.openjdk.java.net/skara/pull/278