Bug 256887 – [git-webkit] pr from a detached head leads to surprising errors

• Component: Tools / Tests
• Status: NEW

[Sam Sneddon [:gsnedders]]

Bug 240468 apparently fixed this, but this once again doesn't work. Clearly we need to be careful about where we push to (what do we call it?), but at the very least we should exit with some more meaningful error (like "cannot push from a detached HEAD") or we should come up with some default branch name to push to.

```
gsnedders@gsnedders-marsha OS2 % git status
interactive rebase in progress; onto 4518454316d9
Last commands done (3 commands done):
   squash b256b58e80bd Test W3C import with existing tests-options.json data https://bugs.webkit.org/show_bug.cgi?id=256851
   break
  (see more in file /Volumes/gsnedders/projects/Safari/OpenSource/.git/worktrees/OS2/rebase-merge/done)
No commands remaining.
You are currently editing a commit while rebasing branch 'wpt-importer-extra-unittests-256851' on '4518454316d9'.
  (use "git commit --amend" to amend the current commit)
  (use "git rebase --continue" once you are satisfied with your changes)

nothing to commit, working tree clean
gsnedders@gsnedders-marsha OS2 % ./Tools/Scripts/git-webkit pr
branch 'main' set up to track 'origin/main'.
    Found 1 commit...
Total errors found: 0 in 1 files
error: The destination you provided is not a full refname (i.e.,
starting with "refs/"). We tried to guess what you meant by:

- Looking for a ref that matches 'HEAD' on the remote side.
- Checking if the <src> being pushed ('HEAD')
  is a ref in "refs/{heads,tags}/". If so we add a corresponding
  refs/{heads,tags}/ prefix on the remote side.

Neither worked, so we gave up. You must fully qualify the ref.
hint: The <src> part of the refspec is a commit object.
hint: Did you mean to create a new branch by pushing to
hint: 'HEAD:refs/heads/HEAD'?
error: failed to push some refs to 'github.com:gsnedders/WebKit.git'
Failed to push 'HEAD' to 'fork' (alias of '[e-mail]:gsnedders/WebKit.git')
Your checkout may be mis-configured, try re-running 'git-webkit setup' or
your checkout may not have permission to push to '[e-mail]:gsnedders/WebKit.git'
```

[Radar WebKit Bug Importer]

<rdar://problem/109453606>