Use hg archive for Mercurial mode=copy

[Almad]

On mode=copy, Buildbot is using cp -rp for copying source to build, copying whole history of repository.

Using hg archive source build would copy only tip, speeding up whole process a lot for bigger repositories.

[Almad]

hg archive instead of cp -rp for mercurial backend

[Almad]

I'vee attached patch that works for me in our environment.

However, this patch breaks tests for mercurial. After examining tests, I guess it's feature: hg archive copies actual repository version, while cp -rp copies working copy version - and tests are using touch to add new files to repo, not followed by add+commit.

From buildbot's perspective, I'd say that mine version makes more sense, as there is no reason to have custom files in repo.

Sending e-mail to -devel list, as this requires "architectonical" change, I guess.

[dustin]

I like this change. Do you think you can fix the tests to not assume the working copy itself will be copied?

[Almad]

Well, I can definitely try, but there was a discussion back there that this should not be default behaviour.

It probably makes sense and whole new mode (mode=export/archive?) should be implemented, which is however too much work for me, as I'm not so familiar with how commands are implemented in bb.

If hg archive is wanted in upstream, I can take a look. Perhaps same change should be implemented for git et al...?

[Almad]

This is related to #276

[marcusl]

There is an export mode in buildbot already. Necessary steps:

• Set the metadir member variable to '.hg' in tests (both Mercurial & MercurialInRepo?)
• The source step should implement this mode, checking self.mode and acting on it as appopriate.

[dustin]

See #669.