revlog: abort on attempt to write null revision
My repo got corrupted yesterday by something that ended up writing the
null revision to the revlog (nullid hash, not nullrev index, of
course). We use many extensions internally (narrowhg, remotefilelog,
evolve, internal extensions) and treemanifests are on. The null
revision was written to the changelog, the root manifest log, and one
subdirectory manifest log. I have no idea exactly why the null
revision was written, but it seems cheap enough to check that we
should fail instead of corrupting the repo.
Differential Revision: https://phab.mercurial-scm.org/D522
syntax: glob
*.elc
*.tmp
*.orig
*.rej
*~
*.mergebackup
*.o
*.so
*.dll
*.exe
*.pyd
*.pyc
*.pyo
*$py.class
*.swp
*.prof
*.zip
\#*\#
.\#*
tests/.coverage*
tests/.testtimes*
tests/.hypothesis
tests/hypothesis-generated
tests/annotated
tests/*.err
tests/htmlcov
build
contrib/chg/chg
contrib/hgsh/hgsh
contrib/vagrant/.vagrant
contrib/docker/debian-*
contrib/docker/ubuntu-*
dist
packages
doc/common.txt
doc/*.[0-9]
doc/*.[0-9].txt
doc/*.[0-9].gendoc.txt
doc/*.[0-9].{x,ht}ml
MANIFEST
MANIFEST.in
patches
mercurial/__modulepolicy__.py
mercurial/__version__.py
mercurial/hgpythonlib.h
mercurial.egg-info
.DS_Store
tags
cscope.*
.idea/*
.asv/*
i18n/hg.pot
locale/*/LC_MESSAGES/hg.mo
hgext/__index__.py
# Generated wheels
wheelhouse/
syntax: regexp
^\.pc/
^\.(pydev)?project
# hackable windows distribution additions
^hg-python
^hg.py$