matcher: make e.g. 'relpath:.' lead to fast paths
Several commands take the fast path when match.always() is
true. However, when the user passes "." on the command line, that
results in a matcher for which match.always() == False. Let's make it
so such matchers return True, and have an empty list of .files(). This
makes e.g. "hg log ." as fast as "hg log" and "hg revert ." as fast as
"hg revert --all" (when run from repo root).
$ for i in aaa zzz; do
> hg init t
> cd t
>
> echo
> echo "-- With $i"
>
> touch file
> hg add file
> hg ci -m "Add"
>
> hg cp file $i
> hg ci -m "a -> $i"
>
> hg cp $i other-file
> echo "different" >> $i
> hg ci -m "$i -> other-file"
>
> hg cp other-file somename
>
> echo "Status":
> hg st -C
> echo
> echo "Diff:"
> hg diff -g
>
> cd ..
> rm -rf t
> done
-- With aaa
Status:
A somename
other-file
Diff:
diff --git a/other-file b/somename
copy from other-file
copy to somename
-- With zzz
Status:
A somename
other-file
Diff:
diff --git a/other-file b/somename
copy from other-file
copy to somename