A symlink's target should never be empty in normal use. Solaris and some BSDs
do allow empty symlinks to be created (with varying semantics on dereference),
but a symlink placeholder that started off as empty is either
- going to be empty, in which case ignoring it is fine, since it's unchanged, or
- going to not be empty, in which case this check is irrelevant.
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.
On Windows, we store symlinks as plain files with the link contents.
Via user error or NFS/Samba assistance, these files often end up with
'normal' file contents. Committing these changes thus gives an
invalid symlink that can't be checked out on Unix.
Here we filter out any modified symlink placeholders that look
suspicious when computing status:
- more than 1K (looks more like a normal file)
- contain NULs (not allowed on Unix, probably a binary)
- contains \n (filenames can't contain \n, very unusual for symlinks,
very common for files)
