Suggestion on git-push --porcelain

Hi,

this is regarding the recent patch series from Larry. (I thought replying to any of the patch messages was appropriate, I couldn't find a cover-letter, so I'm starting a new thread.)

Around June last year, a patch from Larry was made to add the --porcelain option, so as to produce machine-readable output regarding ref status.

The latest patch series goes a step further, and tries to change output - for example, suppressing user-friendly advice and giving "To: <destination>".

I think this is an untenable path - adding/suppressing output of certain messages for porcelain writers, while trying to keep things fixed enough for porcelain writers to depend on. We will also have to keep and eye out for future patches from adding fprintfs to stdout and stderr that may break porcelain scripts.

I believe a better approach would be to prefix messages intended for porcelain writers. For example, a push session might look like this:

  $ git push --porcelain
  PORCELAIN To git://foo.com/git/myrepo.git
  PORCELAIN uptodate refs/heads/baz:refs/heads/baz 1234ab ba4321
  PORCELAIN nonff refs/heads/bar:refs/heads/bar 2345cd 3456de

This is an "positive" approach, in the sense that we don't remove anything from the current output; we just add more printf("PORCELAIN") lines to wherever is appropriate.