ure: Incorrect match offsets with non-ASCII strings

[jepler]

Code:

import re

text1 = "MicroPython loves regular expressions"
text2 = "MicroPython \u2764 regular expressions"

regex1 = re.compile("re")

for text in (text1, text2):
    match = regex1.search(text)
    print(text)
    print("Match:", text[match.start():match.end()])
    print()

Result on standard Python:

$ python3.9 kevin.py 
MicroPython loves regular expressions
Match: re

MicroPython ❤ regular expressions
Match: re

Result on MicroPython v1.19.1-358-g0b26efe73-dirty on 2022-09-03; linux [GCC 10.2.1] version:

./build-coverage/micropython  code.py 
MicroPython loves regular expressions
Match: re

MicroPython ❤ regular expressions
Match: gu

Originally reported at adafruit#6860

My guess (not really an analysis) is that re is failing to convert byte offsets to code-point offsets when it is searching a utf-8 string instead of a bytes object.

[dpgeorge]

Fixed by e90b85c

[jepler]

Thanks!