match: strengthen visit_children_set invariant, Recursive means "all files" My previous interpretation of "Recursive" was too relaxed: I thought it instructed the caller to do something like this: > you can stop calling `visit_children_set` because you'll need to descend into > every directory recursively, but you should still check every file if it > matches or not Whereas the real instruction seems to be: > I guarantee that everything in this subtree matches, you can stop > querying the matcher for all files and dirs altogether. The evidence to support this: - the test actually passes with the stronger invariant, revealing no exceptions from this rule - the implementation of `visit_children_set` for `DifferenceMatcher` clearly relies on this requirement, so it must hold for that not to lead to bugs.

#!/usr/bin/env python3
#
# A tool to help producing large and poorly compressible files
#
# Usage:
#   $TESTDIR/seq.py 1000 | $TESTDIR/sha256line.py > my-file.txt


import hashlib
import sys


for line in sys.stdin:
    print(hashlib.sha256(line.encode('utf8')).hexdigest())