We use a separate cache to avoid problems with
audit = path_auditor(repo.root)
audit("subrepo")
audit("subrepo/file")
whitelisting "subrepo" (which is fine) and then using the same whitelist
with "subrepo/file" (which is not fine).
Since we create a separate path_auditor for every path on the command line,
a "hg add dir/a dir/b dir/c" will still lstat dir 3 times just to audit
the paths.
The following properties of a path are now checked for:
- under top-level .hg
- starts at the root of a windows drive
- contains ".."
- traverses a symlink (e.g. a/symlink_here/b)
- inside a nested repository
If any of these is true, the path is rejected.
The check for traversing a symlink is arguably stricter than necessary;
perhaps we should be checking for symlinks that point outside the
repository.
