convert: add a mode where mercurial_sink skips empty revisions.
The getchanges function of some converter_source classes can return
some false positives. I.e. they sometimes claim that a file "foo"
was changed in some revision, even though its contents are still the
same.
convert_svn is particularly bad, but I think this can also happen with
convert_cvs and, at least in theory, with mercurial_source.
For regular conversions this is not really a problem - as long as
getfile returns the right contents, we'll get a converted revision
with the right contents. But when we use --filemap, this could lead
to superfluous revisions being converted.
Instead of fixing every converter_source, I decided to change
mercurial_sink to work around this problem.
When --filemap is used, we're interested only in revisions that touch
some specific files. If a revision doesn't change any of these files,
then we're not interested in it (at least for revisions with a single
parent; merges are special).
For mercurial_sink, we abuse this property and rollback a commit if
the manifest text hasn't changed. This avoids duplicating the logic
from localrepo.filecommit to detect unchanged files.
#!/bin/sh
hg init test
cd test
cat >sometext.txt <<ENDSOME
This is just some random text
that will go inside the file and take a few lines.
It is very boring to read, but computers don't
care about things like that.
ENDSOME
hg add sometext.txt
hg commit -d "1 0" -m "Just some text"
hg serve -p 20059 -A access.log -E error.log -d --pid-file=hg.pid
cat hg.pid >> $DAEMON_PIDS
("$TESTDIR/get-with-headers.py" localhost:20059 '/?f=f165dc289438;file=sometext.txt;style=raw' content-type content-length content-disposition) >getoutput.txt &
sleep 5
kill `cat hg.pid`
sleep 1 # wait for server to scream and die
cat getoutput.txt
cat access.log error.log | \
sed 's/^[^ ]*\( [^[]*\[\)[^]]*\(\].*\)$/host\1date\2/'