I've rewritten the test case. It's not an infinite loop but rather exponential runtime based on the length of the string. Matching on a string of 'x.x.', increasing the length of the left x or right x by one doubles the runtime. Increasing both quadruples it. 0: 0.0000350475 1: 0.0000259876 2: 0.0000669956 3: 0.0002369881 4: 0.0009140968 5: 0.0038359165 6: 0.0148119926 7: 0.0732769966 8: 0.2570281029 9: 0.9819128513 10: 3.9152498245 11: 16.4304330349 12: 64.8596510887 13: 264.2261950970 I'm not a re guru though, so I don't know if this is a real bug or just one of those special cases re is prone to. Now I just need to find out how to attach my file, SF doesn't want to let me..
Nope, won't let me attach a file. Pasted instead: #!/usr/bin/env python import re from timeit import Timer reexpr = re.compile(r"(.+\n?)+?((\.\n)|(\n\n))") def test(count): text = '%s.%s.' % ('x' * count, 'x' * count) for m in reexpr.finditer(text): pass for count in range(21): print '%2i: %20.10f' % (count, Timer('test(%i)' % count, "from __main__ import test").timeit(number=1))
