use 'x is None' instead of 'x == None'
The built-in None object is a singleton and it is therefore safe to
compare memory addresses with is. It is also faster, how much depends
on the object being compared. For a simple type like str I get:
| s = "foo" | s = None
----------+-----------+----------
s == None | 0.25 usec | 0.21 usec
s is None | 0.17 usec | 0.17 usec
% init
% setup
% delete an empty directory
empty_dir
Removing directory empty_dir
directory
r1
% delete an untracked directory
untracked_dir/untracked_file1
untracked_dir/untracked_file2
Removing file untracked_dir/untracked_file1
Removing file untracked_dir/untracked_file2
Removing directory untracked_dir
directory
r1
% delete an untracked file
untracked_file
untracked_file_readonly
Removing file untracked_file
Removing file untracked_file_readonly
directory
r1
% delete an untracked file in a tracked directory
directory/untracked_file
Removing file directory/untracked_file
directory
r1
% delete nested directories
untracked_directory/nested_directory
Removing directory untracked_directory/nested_directory
Removing directory untracked_directory
directory
r1
% delete nested directories from a subdir
untracked_directory/nested_directory
Removing directory untracked_directory/nested_directory
Removing directory untracked_directory
directory
r1
% delete only part of the tree
untracked_directory/nested_directory
Removing directory untracked_directory/nested_directory
Removing directory untracked_directory
directory
r1
directory/untracked_file
% skip ignored files if --all not specified
directory
ignored
r1
ignored
Removing file ignored
directory
r1
% abort with missing files until we support name mangling filesystems
untracked_file
! r1
? untracked_file
untracked_file
Removing file untracked_file
! r1
% tracked file in ignored directory (issue621)
untracked_file
Removing file untracked_file
% skip excluded files
directory
excluded_file
r1
% skip files in excluded dirs
directory
excluded_dir
r1
file
% skip excluded empty dirs
directory
excluded_dir
r1
% skip patterns