[PATCH v2 0/3] rebase: give precise error message

[Kaartic Sivaraam <kaartic.sivaraam@gmail.com>]

Junio C Hamano <gitster@pobox.com> writes:
> Perhaps time to learn "git symbolic-ref HEAD" and use it instead of
> depending on the name?

Good point. Helped remove the assumption that there's no branch named HEAD.
(and indirectly led to 2 additional patches and the 3 questions found below ;-)


This started as a small fix to make 'git rebase' give a precise
error message when a rebase was done with a detached HEAD. Now it
includes a few cleanups that I caught while analysing the code.

There were a few weird observations when I was anlaysing the code.
They are listed below. Please give your thoughts about them.

The commands I use below were run on my local clone of 'git' and 'origin'
in this context refers to the git mirror at GitHub.

1. "git rebase <upstream> <remote_branch>" does nothing

I tried to play around with rebase by trying out various combinations while
analysing and found the following to have not effect even though the output
doesn't say anything about that,

$ git rebase origin/next origin/maint 
First, rewinding head to replay your work on top of it...
Fast-forwarded origin/maint to origin/next.

IOW, updating a remote branch with a remote upstream had no effect.
Though trying to update a remote branch with a remote upstream doesn't
seem to be very meaningful, the output says it HAS updated the remote
which seems to be misleading. What should be done about this?

2. It's possible to do "git rebase <upstream> <commit>"

$ git origin/next f926f18f3dda0c52e794b2de0911f1b046c7dadf"

This checks out the commit(detaches HEAD) tries to rebase origin/next
from there.

This behaviour doesn't seems to be documented. It says that only a 'branch'
can be specified. (The error message updated in 1/3 previously reported that
the 'branch' name is invalid rather than stating the 'ref (branch/commit) is
invlid')

 git rebase [...] [<upstream> [<branch>]]
 git rebase [...] --root [<branch>]
 ...

Shouldn't it have said that we can give any <ref> apart from <branch> instead of
saying we could give only a <branch>. If intentional, why?

3. "git rebase <upstream> <commit>" shows misleading message

$ git origin/next f926f18f3dda0c52e794b2de0911f1b046c7dadf"
Current branch f926f18f3dda0c52e794b2de0911f1b046c7dadf is up to date.

As it's clear the commit is not a branch. What should be done to fix this?


Kaartic Sivaraam (3):
  rebase: use a more appropriate variable name
  rebase: distinguish user input by quoting it
  rebase: rebasing can also be done when HEAD is detached

 git-rebase.sh | 46 +++++++++++++++++++++++++++++++---------------
 1 file changed, 31 insertions(+), 15 deletions(-)

-- 
2.15.0.345.gf926f18f3