Re: [PATCH v4 00/13] New remote-hg helper

On Thu, Nov 1, 2012 at 12:14 AM, Daniel Barkalow [off-list ref] wrote:

I think that may be true where you have "next" in both places, but I
think:

$ git checkout -b new-branch master
$ git fast-export ^master new-branch

ought to emit no "commit" lines, but needs to emit a "reset" line. After
all, you haven't told fast-export that the ref "new-branch" is up to date,
and you have told it that you want it to be exported. If you create a new
branch off of an existing commit, don't change it, and push it to hg, it
shouldn't be up to remote-hg to figure out what should happen with no
input; it should get a:

reset refs/heads/new-branch
from [something]

I don't know why Johannes seems to want [something] not to be a mark
reference (unless he's complaining about getting an invalid mark
reference when there aren't any marks defined), but surely something of
the above form is necessary to tell remote-hg to create the new branch.

I don't know what Johannes wants, but it has been discussed that not
everybody is using marks.

When you use marks, the following patch fixes the issue:

http://article.gmane.org/gmane.comp.version-control.git/208730

I think it would be worth testing that:

$ git checkout -b new-branch master
$ git push hg new-branch

creates the new branch successfully (which I think it does, but wouldn't
if "git fast-export ^master new-branch" actually returned nothing;
parsed_refs gets it from the reset line).

And it does, with the above patch, a similar command is even in the tests.

The reason why 'git fast-export ^master new-branch' returning nothing
doesn't affect, is that transport helpers wouldn't use negative refs
(e.g. ^master). Transport helper passes whatever the uses specifies. I
you say 'new-branch', that's exactly what the transport helper will
receive. It works because transport helpers use marks.

Nobody expects '^master new-branch' to do something useful, everybody
uses marks.

AFAICT, your code relies on getting the behavior that fast-export actually
gives, not the behavior you seem to want or the behavior Johannes seems to
want. And the reason that you don't need any changes to fast-export is
that your process maps marks instead of sha1s.

No. In order to make use of this bug, the user would have to do:

% git push hg ^master new-branch

Otherwise nothing would get pushed, with or without my first patch[1].
To make 'git push hg new-branch' work, you need my second patch[2].

Cheers.

[1] http://article.gmane.org/gmane.comp.version-control.git/208729
[2] http://article.gmane.org/gmane.comp.version-control.git/208730

-- 
Felipe Contreras