The use of the patch name is dangerous when duplicate names exist.
In case of a duplicate name the second patch and all its dependancies
are merged into a single mercurial patch.
The patch identifier (hash) is always unique.
1. removed files were missed
2. hidden files in top directory were not added/removed correctly
3. suppressed spurious warning on adding new files.
4. hg changeset now checked in with original author and date
5. __file__ not supported by pdb.py