tests/test-status-inprocess.py.out

unionrepo: read-only operations on a union of two localrepos

unionrepo is just like bundlerepo without bundles.

The implementation is very similar to bundlerepo, but I don't see any obvious
way to generalize it.

Some most obvious use cases for this would be log and diff across local repos,
as a kind of preview of pulls, for instance:

  $ hg -R union:repo1+repo2 heads
  $ hg -R union:repo1+repo2 log -r REPO1REV -r REPO2REV
  $ hg -R union:repo1+repo2 log -r '::REPO1REV-::REPO2REV'
  $ hg -R union:repo1+repo2 log -r 'ancestor(REPO1REV,REPO2REV)'
  $ hg -R union:repo1+repo2 diff -r REPO1REV -r REPO2REV

This is going to be used in RhodeCode, and Bitbucket already uses something
similar. Having a core implementation would be beneficial.

% creating repo
% add and commit
C test.py
% change
M test.py