cache: safer handling of failing seek when writing revision branch cache
If the seek for some reason fails (perhaps because the file is too short to
search to the requested position), make sure we seek to the start and rewrite
everything.
It is unknown if this fixes a real problem that ever happened.
#require bzr
$ . "$TESTDIR/bzr-definitions"
$ cat > ghostcreator.py <<EOF
> import sys
> from bzrlib import workingtree
> wt = workingtree.WorkingTree.open('.')
>
> message, ghostrev = sys.argv[1:]
> wt.set_parent_ids(wt.get_parent_ids() + [ghostrev])
> wt.commit(message)
> EOF
ghost revisions
$ mkdir test-ghost-revisions
$ cd test-ghost-revisions
$ bzr init -q source
$ cd source
$ echo content > somefile
$ bzr add -q somefile
$ bzr commit -q -m 'Initial layout setup'
$ echo morecontent >> somefile
$ python ../../ghostcreator.py 'Commit with ghost revision' ghostrev
$ cd ..
$ hg convert source source-hg
initializing destination source-hg repository
scanning source...
sorting...
converting...
1 Initial layout setup
0 Commit with ghost revision
$ glog -R source-hg
o 1@source "Commit with ghost revision" files: somefile
|
o 0@source "Initial layout setup" files: somefile
$ cd ..