Patch export

[williewillus]

It would be nice if we had the ability to export commits under the Git email .patch (example: https://patch-diff.githubusercontent.com/raw/facebook/sapling/pull/287.patch)

I use the mailing list patch workflow for some personal projects and would love to use sl to manage the repo, but exporting diffs to mail is a bit difficult right now.

sl export exists, but it's descended from hg export and does not have all the information the Git patch format does (From lines, date, Subject lines, diffstat, unified file diffs)

[sggutier]

I think at the moment the outputs of sl export and sl export --git are pretty much the same, so it seems that we actually dropped support for the non-git export format some time ago, besides the headers you mention. Hopefully sending a fix for including those should not be too hard.

[nemith]

Looks like in hg land this is usually done with the patchbomb extension which adds an email command and looks better than added to export itself? https://www.mercurial-scm.org/wiki/PatchbombExtension

Are extensions a thing with sl?

[sggutier]

@nemith Extensions are also a thing in Sapling (see https://github.com/facebook/sapling/tree/main/eden/scm/edenscm/ext )

I'm not sure how compatible would that extension be with Sapling, however.

[williewillus]

Is changing the output of export okay? If so, I'll take a stab at implementing this.

I'm assuming it's ok since sl export is not documented on the Sapling website, but the current format could be relied on internally. I guess I could add a --email flag though to get around that.

We'd also need some sort of apply command that takes an mbox file containing a commit and applies it to the repo, like git am. Maybe sl import (also inherited from hg and not documented) could be repurposed, or it works out of the box.

[VishalGawade1]

Hello @zzl0 ,
I wanted to check in and see if there’s any update on this issue or if anyone’s actively working on it. If not, I’d be interested in contributing. I was considering either adding an --email flag to sl export or possibly making it an extension, as discussed above.

[zzl0]

@VishalGawade1 I don’t believe anyone is actively working on it. Thank you for your interest—please feel free to take it on!

[VishalGawade1]

@VishalGawade1 I don’t believe anyone is actively working on it. Thank you for your interest—please feel free to take it on!

Thanks a lot! I'll update you soon :)

[VishalGawade1]

Hello @zzl0 ,
So here is what I have done:

1. I added the --email option, which activates email-style formatting when specified.

 ("", "email", False, _("format export in email style")),

2. Inside the export function, if --email is detected, I generate email headers like From, Date, Subject, and Message-Id for each changeset.

if opts.get("email"):
       for idx, rev in enumerate(revs, 1):
           ctx = repo[rev]
           author = ctx.user()
           date_tuple = ctx.date()
           date_str = email.utils.formatdate(date_tuple[0], localtime=True)
           subject = ctx.description().splitlines()[0]
           commit_hash = ctx.hex()
           total_patches = len(revs)

           # Format headers for email style
           ui.write(f"From {commit_hash} {date_str}\n")
           ui.write(f"From: {author}\n")
           ui.write(f"Date: {date_str}\n")
           ui.write(f"Subject: [PATCH {idx}/{total_patches}] {subject}\n")
           ui.write(f"Message-Id: <{commit_hash}@{repo.root}>\n")
           ui.write("Content-Type: text/plain; charset=UTF-8\n")
           ui.write("\n")

3. After the headers, I add the full commit message, followed by diffstat and the actual diff to show file modifications.

# Write the full commit message
           ui.write(ctx.description())
           ui.write("\n\n---\n\n")

            # Include diffstat
           diffopts = patch.diffopts(ui, opts)
           m = scmutil.match(ctx, opts.get("pattern", []), opts)
           diff = patch.diff(repo, ctx.p1(), ctx, m, opts=diffopts)
           diffstat = patch.diffstat(util.iterlines(diff), git=True)
           ui.write(diffstat)
           ui.write("\n\n")

           # Include the diff
           diff = patch.diff(repo, ctx.p1(), ctx, m, opts=diffopts)
           ui.write(''.join(diff))
           ui.write("\n")

4. If --email isn’t specified, the function runs the usual export flow.

else:
      cmdutil.export(
          repo,
          revs,
          fntemplate=opts.get("output"),
          switch_parent=opts.get("switch_parent"),
          opts=patch.diffallopts(ui, opts),
          match=m,
      )

Let me know if this approach works for you, and I can go ahead with raising a PR. Or, if there’s anything else you’d like me to adjust

[VishalGawade1]

Hello @zzl0 ,
Just wanted to check in and see if I can raise a PR for this

[williewillus]

Go ahead :)

[VishalGawade1]

Hello @williewillus ,
I have raised a PR with all the changes, please have a look :)

[zzl0]

@VishalGawade1 sorry for the late reply, how do you think about this comment?