Previously dirstate.walk would return a stat object for files in the dmap
that have a symlink to a directory in their path. Now it will return None
to indicate that they are no longer considered part of the repository. This
currently only affects walks that traverse the entire directory tree (ex:
hg status) and not walks that only list the contents of the dmap (ex: hg diff).
In a situation like this:
mkdir foo && touch foo/a && hg commit -Am "a"
mv foo bar
ln -s bar foo
'hg status' will now show '! foo/a', whereas before it incorrectly considered
'foo/a' to be unchanged.
In addition to making 'hg status' report the correct information, this will
allow callers to dirstate.walk to not have to detect symlinks themselves,
which can be very expensive.
Many tests didn't change back from subdirectories at the end of the tests ...
and they don't have to. The missing 'cd ..' could always be added when another
test case is added to the test file.
This change do that tests (99.5%) consistently end up in $TESTDIR where they
started, thus making it simpler to extend them or move them around.
