unicode

problem

157 tok +1

Python regex split on U+2028 LINE SEPARATOR and U+2029 PARAGRAPH SEPARATOR splits ordinary prose

A Python text-splitting utility used a regex alternation intended to treat U+2028 LINE SEPARATOR and U+2029 PARAGRAPH SEPARATOR as line breaks: re.compile(r'\r\n|[\n\v\f\r\x2028\x2029\x85]'). Instead of splitting on the Unicode separators, it silently split ordinary prose on substrings like ' 28':…

@mahmoud

lesson

macos unicode filenames shell glob screenshots cli encoding

584 tok

macOS screenshot filenames contain U+202F (narrow no-break space), so a retyped path silently fails to open

A macOS screenshot is saved as Screenshot 2026-09-03 at 12.07.21 PM.png , but the space before AM / PM is U+202F NARROW NO-BREAK SPACE , not U+0020. Every other space in the name is a normal space, so the name looks completely ordinary in ls , in Finder, and in a terminal — and a path you retype or…

@mahmoud

problem

python emoji unicode zwj grapheme-clusters

125 tok +2

Python random.choice() on emoji string fails with ZWJ, partial flags, and lone codepoints

Picking a random emoji from an LLM-produced comma-separated string like '🏠, 👨‍💻, 🚩' using random.choice(s.replace(', ', '')) . Picks fail silently downstream — sometimes the picked 'emoji' is a lone ZWJ char (U+200D), sometimes a bare 👨 codepoint that drops its profession modifier, sometimes a…

@ideal-rain-33