Including branch info in git format-patch

Hi all

We have two public branches on the tinyproxy project[1]: master and 1.6. We send patches to the mailing list to get them reviewed before they are applied and pushed to the public repo.

When i use "git format-patch", it doesn't seem to include the branch (or remote) name in the email it creates. So a reader of this mail may not know what branch to apply it on to test it. Aside from adding in branch information manually in the body of the message, is there any other existing way to get git format-patch to include it?

Apologies in advance if this is a stupid question.

		Mukund

Refs:
 1. http://git.banu.com/?p=tinyproxy;a=summary

On Thu, Jun 19, 2008 at 09:12:52PM +0530, Mukund Sivaraman wrote:

No, there isn't a way to do it automatically. On this mailing list, patches are assumed to be on top of "master" unless explicitly indicated otherwise. And we usually just mention it manually.

You could potentially add a config option to put the branch name inside the '[PATCH]' text. This text is generally stripped away before applying, so it would still free up the receiver to apply on whatever branch they wanted. I don't think it would make sense for git development, since we typically use topic branches, so keeping it configurable would make sense.

On the receiving end, the applying party could set up their MUA to split patches based on the subject, and then apply them as appropriate (this very much depends on their workflow for applying patches). You could probably even do a pre-applypatch hook as a safety valve to make sure things were being applied in the right place.

-Peff

Jeff King <peff@peff.net> writes:

People would work on individual patches on topic branches that are named differently from the branch on the other end anyway (the branch that corresonds to the other end will be used for local integration testing in such a setup), so I do not see much point in stating which local branch happened to have been checked out when the patch was generated, in the output.

Also, in git, there is no independent "branch history", so anybody who says "this patch was taken from this branch" is either speaking very loosely, or does not understand git's branching model at all, or bit of both.

If you have a history of this shape:

                    (other cruft)
                          \
                   ----o---o next
                      /
         o---o---o---o master
        /       /
    ---o---o---A

which "branch label" would you give to the format-patch output that shows commit A? It may apply to both master and next, and it is really up to the project's convention what to do with it. The side branch the patch was developed on may be named "quick-hack", which would not have any relevance to the final location of where that patch wants to be in.

On Thu, Jun 19, 2008 at 01:54:15PM -0700, Junio C Hamano wrote:

I think that is totally dependent on the workflow, which is what I was trying to say above. It really depends on how the patch-submitter organizes his branches.

I suspect you would do better to look at branch.quick-hack.merge, so that you say "this was based on upstream's X", not "this is my quick-hack".

But there are so many ways this could go wrong, since the patches you're formatting might not even have anything to do with the branch you're on.

-Peff

On Thu, Jun 19, 2008 at 05:06:17PM -0400, Jeff King wrote:

Side note: if you have a particular workflow, it might make sense, rather than using format-patch directly, to codify that workflow in another script which says "ok, this is how I grab a branch and send it upstream". And in that case, you could look up "here's where I branched from" and feed it into the patch via format-patch's --subject-prefix option.

-Peff

On Thu, Jun 19, 2008 at 10:54 PM, Junio C Hamano <gitster@pobox.com> wrote:

I think what Mukund is asking for is a way to specify what upstream branch the commit should be applied to. This would be a feature to help the person who is going to do the applying, so it is ok if the person formatting the patch has to do a little work for that (e.g., specify which upstream branch to format-patch as a cmdline option)

<snip>

You would give it the label of the branch you want it applied to!

On Thu, Jun 19, 2008 at 01:54:15PM -0700, Junio C Hamano wrote:

I follow what you are saying. In our workflow case, pointing out the remote (public) branch name should be sufficient (as this's the public shared branch among us, and all patchsets shared with others are against the public branches). Perhaps I can add it to the [PATCH] text in the subject line as Jeff suggests.

My problem is that I can't send a patch out to the list for other developers to try, without some annotation for them, of which branch to try it on.

		Mukund

Mukund Sivaraman <muks@banu.com> writes:

So what's wrong telling that when you send out the patch, between the time you run format-patch and send-email?

On Thu, Jun 19, 2008 at 02:41:54PM -0700, Junio C Hamano wrote:

I had asked if there was some way the remote branch name could automatically be inserted by git format-patch, instead of manually adding it in the patch message or in a cover letter. What Jeff suggested seems good to me (of using --subject-prefix) as that is removed automatically when the patch is applied by git am.

		Mukund