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
# @ (34) head
# |
# | o (33) head
# | |
# o | (32) expand
# |\ \
# | o \ (31) expand
# | |\ \
# | | o \ (30) expand
# | | |\ \
# | | | o | (29) regular commit
# | | | | |
# | | o | | (28) merge zero known
# | | |\ \ \
# o | | | | | (27) collapse
# |/ / / / /
# | | o---+ (26) merge one known; far right
# | | | | |
# +---o | | (25) merge one known; far left
# | | | | |
# | | o | | (24) merge one known; immediate right
# | | |\| |
# | | o | | (23) merge one known; immediate left
# | |/| | |
# +---o---+ (22) merge two known; one far left, one far right
# | | / /
# o | | | (21) expand
# |\ \ \ \
# | o---+-+ (20) merge two known; two far right
# | / / /
# o | | | (19) expand
# |\ \ \ \
# +---+---o (18) merge two known; two far left
# | | | |
# | o | | (17) expand
# | |\ \ \
# | | o---+ (16) merge two known; one immediate right, one near right
# | | |/ /
# o | | | (15) expand
# |\ \ \ \
# | o-----+ (14) merge two known; one immediate right, one far right
# | |/ / /
# o | | | (13) expand
# |\ \ \ \
# +---o | | (12) merge two known; one immediate right, one far left
# | | |/ /
# | o | | (11) expand
# | |\ \ \
# | | o---+ (10) merge two known; one immediate left, one near right
# | |/ / /
# o | | | (9) expand
# |\ \ \ \
# | o-----+ (8) merge two known; one immediate left, one far right
# |/ / / /
# o | | | (7) expand
# |\ \ \ \
# +---o | | (6) merge two known; one immediate left, one far left
# | |/ / /
# | o | | (5) expand
# | |\ \ \
# | | o | | (4) merge two known; one immediate left, one immediate right
# | |/|/ /
# | o / / (3) collapse
# |/ / /
# o / / (2) collapse
# |/ /
# o / (1) collapse
# |/
# o (0) root
set -e
commit()
{
rev=$1
msg=$2
shift 2
if [ "$#" -gt 0 ]; then
hg debugsetparents "$@"
fi
echo $rev > $rev
hg add $rev
hg ci -d "$rev 0" -m "($rev) $msg"
}
echo "[extensions]" >> $HGRCPATH
echo "graphlog=" >> $HGRCPATH
echo % init
hg init repo
cd repo
echo % empty repo
hg glog
echo % building tree
commit 0 "root"
commit 1 "collapse" 0
commit 2 "collapse" 1
commit 3 "collapse" 2
commit 4 "merge two known; one immediate left, one immediate right" 1 3
commit 5 "expand" 3 4
commit 6 "merge two known; one immediate left, one far left" 2 5
commit 7 "expand" 2 5
commit 8 "merge two known; one immediate left, one far right" 0 7
commit 9 "expand" 7 8
commit 10 "merge two known; one immediate left, one near right" 0 6
commit 11 "expand" 6 10
commit 12 "merge two known; one immediate right, one far left" 1 9
commit 13 "expand" 9 11
commit 14 "merge two known; one immediate right, one far right" 0 12
commit 15 "expand" 13 14
commit 16 "merge two known; one immediate right, one near right" 0 1
commit 17 "expand" 12 16
commit 18 "merge two known; two far left" 1 15
commit 19 "expand" 15 17
commit 20 "merge two known; two far right" 0 18
commit 21 "expand" 19 20
commit 22 "merge two known; one far left, one far right" 18 21
commit 23 "merge one known; immediate left" 1 22
commit 24 "merge one known; immediate right" 0 23
commit 25 "merge one known; far left" 21 24
commit 26 "merge one known; far right" 18 25
commit 27 "collapse" 21
commit 28 "merge zero known" 1 26
commit 29 "regular commit" 0
commit 30 "expand" 28 29
commit 31 "expand" 21 30
commit 32 "expand" 27 31
commit 33 "head" 18
commit 34 "head" 32
echo % glog -q
hg glog -q
echo % glog
hg glog
echo % unused arguments
hg glog -q foo || echo failed