Re: grep open pull requests

2017-01-19 Thread Jeff King 
On Thu, Jan 19, 2017 at 03:12:53PM -0700, Jack Bates wrote:

> Cool, thanks for all your help! "git log --cherry-pick" works quite well.
> One thing: I expected the following to be equivalent, but found that they're
> not. Is that by accident or design?
> 
>   $ git rev-list --cherry-pick --right-only master...refs/pull/1112/head
>   $ git rev-list --cherry-pick master..refs/pull/1112/head

It's by design. The "left" and "right" notions are defined only for a
three-dot symmetric difference.

In the first command you've asked git to look at commits on _both_
master and the PR, down to their merge base. It marks the tips with a
"left" and "right" bit, and then those bits propagate down.

In the second command, you've only asked for the PR commits, and there
is no left/right bit at all. So --cherry-pick is doing nothing, as it
has no "left" commits to compare to.

-Peff

Re: grep open pull requests

2017-01-19 Thread Jack Bates 

On 19/01/17 12:02 PM, Jeff King wrote:

It's much trickier to find from the git topology whether a particular
history contains rebased versions of commits.  You can look at the
--cherry options to "git log", which use patch-ids to try to equate
commits. Something like:

  git for-each-ref --format='%(refname)' 'refs/pull/*/head' |
  while read refname; do
if test -z "$(git rev-list --right-only --cherry-pick -1 
origin...$refname)
then
echo "$refname: not merged"
fi
  done

That's obviously much less efficient than `--no-merged`, but it should
generally work. The exception is if the rebase changed the commit
sufficiently that its patch-id may have changed.


Cool, thanks for all your help! "git log --cherry-pick" works quite 
well. One thing: I expected the following to be equivalent, but found 
that they're not. Is that by accident or design?


  $ git rev-list --cherry-pick --right-only master...refs/pull/1112/head
  $ git rev-list --cherry-pick master..refs/pull/1112/head


I think that's probably the best answer to your "unmerged" question,
too. Ask the API which PRs are unmerged, and then do whatever git-level
analysis you want based on that.


Right, that makes sense. Thanks again!

Re: grep open pull requests

2017-01-19 Thread Jeff King 
On Thu, Jan 19, 2017 at 11:12:03AM -0700, Jack Bates wrote:

> I have a couple questions around grepping among open pull requests.
> 
> First, "git for-each-ref --no-merged": When I run the following,
> it lists refs/pull/1112/head, even though #1112 was merged in commit
> ced4da1. I guess this is because the tip of refs/pull/1112/head is 107fc59,
> not ced4da1?

Right. Git's `--no-merged` is about commit ancestry.

> This maybe shows my lack of familiarity with Git details,
> but superficially the two commits appear identical -- [1] and [2] --
> same parent, etc. Nonetheless they have different SHA-1s.
> I'm not sure why that is -- I didn't merge the commit --
> but regardless, GitHub somehow still connects ced4da1 with #1112.

The commits differ only in the committer timestamp. Try:

  diff -u <(git cat-file commit 107fc5910) \
  <(git cat-file commit ced4da132)

Is it possible that somebody cherry-pick or rebased it? Looking at the
history of apache/trafficserver, I don't see any merges, which implies
to me that the project is using a rebase workflow to merge PRs.

It's much trickier to find from the git topology whether a particular
history contains rebased versions of commits.  You can look at the
--cherry options to "git log", which use patch-ids to try to equate
commits. Something like:

  git for-each-ref --format='%(refname)' 'refs/pull/*/head' |
  while read refname; do
if test -z "$(git rev-list --right-only --cherry-pick -1 
origin...$refname)
then
echo "$refname: not merged"
fi
  done

That's obviously much less efficient than `--no-merged`, but it should
generally work. The exception is if the rebase changed the commit
sufficiently that its patch-id may have changed.

> So my question is, how are they doing that,

I suspect the answer is "somebody clicked the rebase button GitHub"
which simultaneously did the rebase and marked the PR as merged.

> Lastly, a question more about GitHub than Git, but: Given the way GitHub is
> setup, I hope I can get a list of unmerged pull requests from Git alone. Can
> you think of a way to list *open* pull requests,
> or is that status only available out of band?

That information isn't reflected in the git topology. It's in GitHub's
database. You can ask the API:

  https://developer.github.com/v3/

There are libraries to help with that:

  https://developer.github.com/libraries/

I think that's probably the best answer to your "unmerged" question,
too. Ask the API which PRs are unmerged, and then do whatever git-level
analysis you want based on that.

-Peff