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Title: gh-145234: Fix SystemError in parser when \r is introduced after code… by gourijain029-del · Pull Request #145276 · python/cpython · GitHub

Open Graph Title: gh-145234: Fix SystemError in parser when \r is introduced after code… by gourijain029-del · Pull Request #145276 · python/cpython

X Title: gh-145234: Fix SystemError in parser when \r is introduced after code… by gourijain029-del · Pull Request #145276 · python/cpython

Description: Description This PR fixes a SystemError: Parser/string_parser.c:286: bad argument to internal function that occurred when a Python file used an encoding (like UTF-7) that introduced \r characters after decoding. Root Cause The crash was caused by a synchronization failure between the tokenizer, the lexer, and the string parser: Tokenizer: When the file tokenizer recoded a line (e.g., from UTF-7 to UTF-8), it was not normalizing newlines. If the codec introduced a \r, it remained in the buffer. Lexer: The lexer skipped \r characters but did not correctly trigger "beginning-of-line" (atbol) logic. This meant that if a \r followed a comment (#...), the lexer would remain in a state where it thought it was still on the same line, causing it to merge the comment and the subsequent string literal into a single, invalid token. String Parser: When _PyPegen_parse_string received this broken token (which didn't start with a quote character), it raised a SystemError. Changes Parser/lexer/lexer.c : Updated the lexer to treat a standalone \r as a full newline. It now correctly sets atbol = 1 and resets the current token start, preventing the "merging" of tokens across lines. Parser/tokenizer/file_tokenizer.c : Updated tok_readline_recode to explicitly call _PyTokenizer_translate_newlines on the UTF-8 decoded buffer. Optimized tok_underflow_file to immediately discard and re-decode the buffer as soon as a coding spec is identified, preventing raw bytes from leaking into the parser. Lib/test/test_parser_utf7_r.py : Added a new regression test that uses a UTF-7 encoded \r to reproduce the original crash. Issue: gh-145234

Open Graph Description: Description This PR fixes a SystemError: Parser/string_parser.c:286: bad argument to internal function that occurred when a Python file used an encoding (like UTF-7) that introduced \r characters a...

X Description: Description This PR fixes a SystemError: Parser/string_parser.c:286: bad argument to internal function that occurred when a Python file used an encoding (like UTF-7) that introduced \r characters a...

Opengraph URL: https://github.com/python/cpython/pull/145276

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