performance: do not stat() things when not required
Ignore unknown files if we don't need them (eg in hg diff).
It slows things down a little bit for big trees (kernel repo), since _join()
is called for each file instead of for each directory.
fix issue567
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
created new head
% Merging a conflict araises
merging A
warning: conflicts during merge.
merging A failed!
1 files updated, 0 files merged, 0 files removed, 1 files unresolved
use 'hg resolve' to retry unresolved file merges
% Correct the conflict without marking the file as resolved
abort: unresolved merge conflicts (see hg resolve)
% Mark the conflict as resolved and commit