tests/test-mq-merge

convert: fix mercurial_sink.putcommit

Changeset 4ebc8693ce72 added some code to putcommit to avoid creating a
revision that touches no files, but this can break regular conversions
from some repositories:

- conceptually, since we're converting a repo, we should try to make
  the new hg repo as similar as possible to the original repo - we
  should create a new changeset, even if the original revision didn't
  touch any files (maybe the commit message had some important bit);

- even if a "regular" revision that doesn't touch any file may seem
  weird (and maybe even broken), it's completely legitimate for a merge
  revision to not touch any file, and, if we just skip it, the
  converted repo will end up with wrong history and possibly an extra
  head.

  As an example, say the crew and main hg repos are sync'ed.  Somebody
  sends an important patch to the mailing list.  Matt quickly applies
  and pushes it.  But at the same time somebody also applies it to crew
  and pushes it.  Suppose the commit message ended up being a bit
  different (say, there was a typo and somebody didn't fix it) or that
  the date ended up being different (because of different patch-applying
  scripts): the changeset hashes will be different, but the manifests
  will be the same.

  Since both changesets were pushed to public repos, it's hard to recall
  them.  If both are merged, the manifest from the resulting merge
  revision will have the exact same contents as its parents - i.e. the
  merge revision really doesn't touch any file at all.

To keep the file filtering stuff "working", the generic code was changed
to skip empty revisions if we're filtering the repo, fixing a bug in the
process (we want parents[0] instead of tip).

#!/bin/sh

# Test issue 529 - mq aborts when merging patch deleting files

rewrite_path()
{
    sed -e 's:\\:/:g' -e 's:[^ ]*/t/::g'
}

echo "[extensions]" >> $HGRCPATH
echo "hgext.mq=" >> $HGRCPATH

# Commit two dummy files in "init" changeset
hg init t
cd t
echo a > a
echo b > b
hg ci -Am init
hg tag -l init

# Create a patch removing a
hg qnew rm_a
hg rm a
hg qrefresh -m "rm a"

# Save the patch queue so we can merge it later
hg qsave -c -e 2>&1 | rewrite_path

# Update b and commit in an "update" changeset
hg up -C init
echo b >> b
hg st
hg ci -m update

# Here, qpush used to abort with :
# The system cannot find the file specified => a
hg manifest
hg qpush -a -m 2>&1 | rewrite_path
hg manifest

# ensure status is correct after merge
hg qpop -a