rust-revlog: fix RevlogEntry.data() for NULL_REVISION
Before this change, the pseudo-entry returned by `Revlog.get_entry` for
`NULL_REVISION` would trigger errors in application code using it.
For example, this fixes a crash spotted with changelog data
while implementing RHGitaly: `Changelog.data_for_rev(-1)` was already
returning the pseudo content as expected, e.g., for `hg log`, but
`Changelog.entry_for_rev(-1).data()` would still crash with
"corrupted revlog, hash check failed for revision -1". There is
an added test for this scenario.
$ hgserve() {
> hg serve -a localhost -p $HGPORT1 -d --pid-file=hg.pid \
> -E errors.log -v $@ > startup.log
> # Grepping hg serve stdout would hang on Windows
> grep -v 'listening at' startup.log
> cat hg.pid >> "$DAEMON_PIDS"
> }
$ hg init a
$ hg --encoding utf-8 -R a branch æ
marked working directory as branch \xc3\xa6 (esc)
(branches are permanent and global, did you want a bookmark?)
$ echo foo > a/foo
$ hg -R a ci -Am foo
adding foo
$ hgserve -R a --config web.push_ssl=False --config web.allow_push=* --encoding latin1
$ hg --encoding utf-8 clone http://localhost:$HGPORT1 b
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
new changesets 867c11ce77b8
updating to branch \xc3\xa6 (esc)
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg --encoding utf-8 -R b log
changeset: 0:867c11ce77b8
branch: \xc3\xa6 (esc)
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: foo
$ echo bar >> b/foo
$ hg -R b ci -m bar
$ hg --encoding utf-8 -R b push
pushing to http://localhost:$HGPORT1/
searching for changes
remote: adding changesets
remote: adding manifests
remote: adding file changes
remote: added 1 changesets with 1 changes to 1 files
$ hg -R a --encoding utf-8 log
changeset: 1:58e7c90d67cb
branch: \xc3\xa6 (esc)
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: bar
changeset: 0:867c11ce77b8
branch: \xc3\xa6 (esc)
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: foo
$ killdaemons.py hg.pid
verify 7e7d56fe4833 (encoding fallback in branchmap to maintain compatibility with 1.3.x)
$ cat <<EOF > oldhg
> import threading
> from mercurial import dispatch, hg, ui, wireprotoserver
>
> class StdoutWrapper(object):
> def __init__(self, stdout):
> self._file = stdout
>
> def write(self, data):
> if data == b'47\n':
> # latin1 encoding is one %xx (3 bytes) shorter
> data = b'44\n'
> elif data.startswith(b'%C3%A6 '):
> # translate to latin1 encoding
> data = b'%%E6 %s' % data[7:]
> self._file.write(data)
>
> def __getattr__(self, name):
> return getattr(self._file, name)
>
> dispatch.initstdio()
> myui = ui.ui.load()
> fout = StdoutWrapper(myui.fout)
> myui.fout = myui.ferr
> repo = hg.repository(myui, b'a')
> wireprotoserver._runsshserver(myui, repo, myui.fin, fout, threading.Event())
> EOF
$ echo baz >> b/foo
$ hg -R b ci -m baz
$ hg push -R b -e "\"$PYTHON\" oldhg" ssh://dummy/ --encoding latin1
pushing to ssh://dummy/
searching for changes
remote: adding changesets
remote: adding manifests
remote: adding file changes
remote: added 1 changesets with 1 changes to 1 files