tests/test-merge4.t

bundle2: fix bundle2 pulling all revs on empty pulls

When bundle2 was enabled, if hg pull had no commits to pull, it would print
'no changes found' and then download the entire repository from the server. This
was caused by heads and common being set to None, which gets treated as
heads=cl.heads() and common=[nullid], which means download the entire repo.

Pulling bundles without a changegroup is a valid use case (like if we're just
updating bookmarks), so this modifes the bundle code to allow not adding
changegroups.

This is backport of ab5040cd5749.

  $ hg init
  $ echo This is file a1 > a
  $ hg add a
  $ hg commit -m "commit #0"
  $ echo This is file b1 > b
  $ hg add b
  $ hg commit -m "commit #1"
  $ hg update 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo This is file c1 > c
  $ hg add c
  $ hg commit -m "commit #2"
  created new head
  $ hg merge 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ rm b
  $ echo This is file c22 > c

Test hg behaves when committing with a missing file added by a merge

  $ hg commit -m "commit #3"
  abort: cannot commit merge with missing files
  [255]