revbranchcache: return uncached branchinfo for nullrev (
issue4683)
This fixes the crash caused by "branch(null)" revset. No cache should be
necessary for nullrev because changelog.branchinfo(nullrev) does not involve
IO operation.
Note that the problem of "branch(wdir())" isn't addressed by this patch.
"wdir()" will raise TypeError in many places because of None. This is the
reason why "wdir()" is still experimental.
$ hg init
$ echo 123 > a
$ hg add a
$ hg commit -m "first" a
$ mkdir sub
$ echo 321 > sub/b
$ hg add sub/b
$ hg commit -m "second" sub/b
$ cat sub/b
321
$ hg co 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ cat sub/b 2>/dev/null || echo "sub/b not present"
sub/b not present
$ test -d sub || echo "sub not present"
sub not present