absorb: preserve changesets which were already empty
Most commands in Mercurial (commit, rebase, absorb itself) don’t create empty
changesets or drop them if they become empty. If there’s a changeset that’s
empty, it must be a deliberate choice of the user. At least it shouldn’t be
absorb’s responsibility to prune them. The fact that changesets that became
empty during absorb are pruned, is unaffected by this.
This case was found while writing patches which make it possible to configure
absorb and rebase to not drop empty changesets. Even without having such config
set, I think it’s valuable to preserve changesets which were already empty.
#testcases sshv1 sshv2
#if sshv2
$ cat >> $HGRCPATH << EOF
> [experimental]
> sshpeer.advertise-v2 = true
> sshserver.support-v2 = true
> EOF
#endif
$ cat > bundle2.py << EOF
> """A small extension to test bundle2 pushback parts.
> Current bundle2 implementation doesn't provide a way to generate those
> parts, so they must be created by extensions.
> """
> from __future__ import absolute_import
> from mercurial import bundle2, exchange, pushkey, util
> def _newhandlechangegroup(op, inpart):
> """This function wraps the changegroup part handler for getbundle.
> It issues an additional pushkey part to send a new
> bookmark back to the client"""
> result = bundle2.handlechangegroup(op, inpart)
> if b'pushback' in op.reply.capabilities:
> params = {b'namespace': b'bookmarks',
> b'key': b'new-server-mark',
> b'old': b'',
> b'new': b'tip'}
> encodedparams = [(k, pushkey.encode(v))
> for (k, v) in params.items()]
> op.reply.newpart(b'pushkey', mandatoryparams=encodedparams)
> else:
> op.reply.newpart(b'output', data=b'pushback not enabled')
> return result
> _newhandlechangegroup.params = bundle2.handlechangegroup.params
> bundle2.parthandlermapping[b'changegroup'] = _newhandlechangegroup
> EOF
$ cat >> $HGRCPATH <<EOF
> [ui]
> ssh = "$PYTHON" "$TESTDIR/dummyssh"
> username = nobody <no.reply@example.com>
>
> [alias]
> tglog = log -G -T "{desc} [{phase}:{node|short}]"
> EOF
Set up server repository
$ hg init server
$ cd server
$ echo c0 > f0
$ hg commit -Am 0
adding f0
Set up client repository
$ cd ..
$ hg clone ssh://user@dummy/server client -q
$ cd client
Enable extension
$ cat >> $HGRCPATH <<EOF
> [extensions]
> bundle2=$TESTTMP/bundle2.py
> EOF
Without config
$ cd ../client
$ echo c1 > f1
$ hg commit -Am 1
adding f1
$ hg push
pushing to ssh://user@dummy/server
searching for changes
remote: adding changesets
remote: adding manifests
remote: adding file changes
remote: added 1 changesets with 1 changes to 1 files
remote: pushback not enabled
$ hg bookmark
no bookmarks set
$ cd ../server
$ hg tglog
o 1 [public:2b9c7234e035]
|
@ 0 [public:6cee5c8f3e5b]
With config
$ cd ../client
$ echo '[experimental]' >> .hg/hgrc
$ echo 'bundle2.pushback = True' >> .hg/hgrc
$ echo c2 > f2
$ hg commit -Am 2
adding f2
$ hg push
pushing to ssh://user@dummy/server
searching for changes
remote: adding changesets
remote: adding manifests
remote: adding file changes
remote: added 1 changesets with 1 changes to 1 files
$ hg bookmark
new-server-mark 2:0a76dfb2e179
$ cd ../server
$ hg tglog
o 2 [public:0a76dfb2e179]
|
o 1 [public:2b9c7234e035]
|
@ 0 [public:6cee5c8f3e5b]