Question about "bzr merge --force"

[Greg Ward]

It appears that Bazaar 1.13 has a change that breaks one of
Mercurial's tests, specifically the test for converting a Bazaar repo
with merges.  In particular, Mercurial's test-convert-bzr-merges
script does this:

  cd ../source
  bzr merge -q ../source-branch1
  bzr merge -q --force ../source-branch2
  bzr commit -q -m 'Merged branches'

which presumably worked as expected with some past version of Bazaar
-- i.e. it let you jam two merges together into one commit.

With Bazaar 1.13, the "merge --force" fails:

bzr: ERROR: Working tree
"/home/greg/src/hg/tests/tmp/test-multimerge/source/" has uncommitted
changes.

even though "bzr help merge" says

  --force               Merge even if the destination tree has uncommitted
                        changes.

Is this a bug in Bazaar 1.13?  Or a deliberate change to disallow
jamming two merges into one commit?

Thanks --

Greg