threads / discuss / 42941

Find a topic branch containing a commit

Subject: Find a topic branch containing a commit

## tl;dr

7 messages between Jul 27, 2016 and Jul 28, 2016.

replies: 6people: 4as markdown or json

Duy Nguyen· Jul 27, 2016, 17:42 UTC · lore

Before I start doing anything silly because I don't know it can already be done without waving my C wand like a mad man...

I often do this: find a commit of interest, the commit itself is not enough so I need a full patch series to figure out what's going, so I fire up "git log --graph --oneline" and manually search that commit and trace back to the merge point, then I can "git log --patch". Is there an automatic way to accomplish that? Something like "git branch --contains" (or "git merge --contains")?

PS. Sometimes I wish we could optionally save cover letter in the merge commit. Sometimes the "big plan" is hard to see by reading individual commit messages.

-- 
Duy

Stefan Beller· Jul 27, 2016, 17:50 UTC · re: Duy Nguyen · lore

Re: Find a topic branch containing a commit

On Wed, Jul 27, 2016 at 10:42 AM, Duy Nguyen <pclouds@gmail.com> wrote:

Show 9 quoted lines

> Before I start doing anything silly because I don't know it can
> already be done without waving my C wand like a mad man...
>
> I often do this: find a commit of interest, the commit itself is not
> enough so I need a full patch series to figure out what's going, so I
> fire up "git log --graph --oneline" and manually search that commit
> and trace back to the merge point, then I can "git log --patch". Is
> there an automatic way to accomplish that? Something like "git branch
> --contains" (or "git merge --contains")?

https://github.com/mhagger/git-when-merged ?

Show 10 quoted lines

>
> PS. Sometimes I wish we could optionally save cover letter in the
> merge commit. Sometimes the "big plan" is hard to see by reading
> individual commit messages.
> --
> Duy
> --
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Stefan Beller· Jul 27, 2016, 18:02 UTC · re: Stefan Beller · lore

Re: Find a topic branch containing a commit

On Wed, Jul 27, 2016 at 10:50 AM, Stefan Beller <sbeller@google.com> wrote:

Show 5 quoted lines

>>
>> PS. Sometimes I wish we could optionally save cover letter in the
>> merge commit. Sometimes the "big plan" is hard to see by reading
>> individual commit messages.
>> --

I had this wish, too. That makes a lot of sense for merge commits, although it doesn't work well with our current workflow I would presume, because the merge commit happens at a different time than when Junio picks up a patch series. And in the mean time, where would we store the cover letter information to not get lost?

Note there are some external recordings instead of adding it to the history itself, e.g. https://github.com/trast/git/tree/notes/gmane annotated each commit with pointers to the mailing list archive.

Duy Nguyen· Jul 27, 2016, 18:07 UTC · re: Stefan Beller · lore

Re: Find a topic branch containing a commit

On Wed, Jul 27, 2016 at 8:02 PM, Stefan Beller <sbeller@google.com> wrote:

Show 12 quoted lines

> On Wed, Jul 27, 2016 at 10:50 AM, Stefan Beller <sbeller@google.com> wrote:
>>>
>>> PS. Sometimes I wish we could optionally save cover letter in the
>>> merge commit. Sometimes the "big plan" is hard to see by reading
>>> individual commit messages.
>>> --
>
> I had this wish, too. That makes a lot of sense for merge commits,
> although it doesn't work well with our current workflow I would presume,
> because the merge commit happens at a different time than when Junio
> picks up a patch series. And in the mean time, where would we
> store the cover letter information to not get lost?

We have config branch.xxx.description for that. If we teach git-am to pick up (a selected portion of) the cover letter and save it in branch.xxx.description (or even a new key like branch.xxx.mergeMsg) then nothing is lost.

-- 
Duy

Duy Nguyen· Jul 27, 2016, 18:03 UTC · re: Stefan Beller · lore

Re: Find a topic branch containing a commit

On Wed, Jul 27, 2016 at 7:50 PM, Stefan Beller <sbeller@google.com> wrote:

Show 12 quoted lines

> On Wed, Jul 27, 2016 at 10:42 AM, Duy Nguyen <pclouds@gmail.com> wrote:
>> Before I start doing anything silly because I don't know it can
>> already be done without waving my C wand like a mad man...
>>
>> I often do this: find a commit of interest, the commit itself is not
>> enough so I need a full patch series to figure out what's going, so I
>> fire up "git log --graph --oneline" and manually search that commit
>> and trace back to the merge point, then I can "git log --patch". Is
>> there an automatic way to accomplish that? Something like "git branch
>> --contains" (or "git merge --contains")?
>
> https://github.com/mhagger/git-when-merged ?

Beautiful. If it had an option to show a topic (i.e. git-log from merge base to merge point) I would be ecstatic. Michael, any plans on bringing this in C Git? For many topic-based projects this would be very helpful addition, and I think it's not so hard to do it in C either.

-- 
Duy

Michael Haggerty· Jul 28, 2016, 13:46 UTC · re: Duy Nguyen · lore

Re: Find a topic branch containing a commit

On 07/27/2016 08:03 PM, Duy Nguyen wrote:

Show 16 quoted lines

> On Wed, Jul 27, 2016 at 7:50 PM, Stefan Beller <sbeller@google.com> wrote:
>> On Wed, Jul 27, 2016 at 10:42 AM, Duy Nguyen <pclouds@gmail.com> wrote:
>>> Before I start doing anything silly because I don't know it can
>>> already be done without waving my C wand like a mad man...
>>>
>>> I often do this: find a commit of interest, the commit itself is not
>>> enough so I need a full patch series to figure out what's going, so I
>>> fire up "git log --graph --oneline" and manually search that commit
>>> and trace back to the merge point, then I can "git log --patch". Is
>>> there an automatic way to accomplish that? Something like "git branch
>>> --contains" (or "git merge --contains")?
>>
>> https://github.com/mhagger/git-when-merged ?
> 
> Beautiful. If it had an option to show a topic (i.e. git-log from
> merge base to merge point) I would be ecstatic.

That's a good idea. I just created a pull request to add that feature:

    https://github.com/mhagger/git-when-merged/pull/13

Let me know what you think!

> Michael, any plans on
> bringing this in C Git? For many topic-based projects this would be
> very helpful addition, and I think it's not so hard to do it in C
> either.

I had no such plans, and I don't have time to work on that now. But I certainly don't object if somebody else wants to work on it. It might make a nice GSoC-sized project (though I'm not volunteering to be a mentor at this time :-P ).

Michael

Junio C Hamano· Jul 28, 2016, 15:11 UTC · re: Michael Haggerty · lore

Re: Find a topic branch containing a commit

Michael Haggerty <mhagger@alum.mit.edu> writes:

Show 12 quoted lines

> On 07/27/2016 08:03 PM, Duy Nguyen wrote:
>>>
>>> https://github.com/mhagger/git-when-merged ?
>> 
>> Beautiful. If it had an option to show a topic (i.e. git-log from
>> merge base to merge point) I would be ecstatic.
>
> That's a good idea. I just created a pull request to add that feature:
>
>     https://github.com/mhagger/git-when-merged/pull/13
>
> Let me know what you think!

It would be nice to have a mode to give the result in a more human readable way.

I use when-merged to find where to queue a follow-on fix to a topic that has already graduated to 'master'. When the patch fixes an earlier mistake of the commit X, "git when-merged X master" gives me the merge's 40-hex object name, and the next step is almost always to pass it to "git describe [--contains]". This tells me down to which maintenace track the fix can go.

Of course I can get that information by running a separate "git describe [--contains] X", but when I'll be running "when-merged" anyway, it is a wasted step.

Then "git show" of the found merge tells me where the tip of the topic is and what the topic was called (older topic branches are culled sometime after they are merged to 'master' and relevant maintenance tracks), and allows me to queue the patch to the correct place (after re-creating the topic if necessary).