Distillation

Date: Sep 9, 2026

• 🟡 (15:08) A ZIP/compression probe produced three exact result rows: 1810 61 1810 True False 0xc27b61de, 16 18 16 True False 0x22ccea73, and 1825 75 1824 False False 0xd3f37109.
• 🟡 (15:09) Python 3.12 ZIP implementation inspected at /usr/lib/python3.12/zipfile/__init__.py:671-719: LZMACompressor lazily initializes a raw lzma.LZMACompressor using lzma.FILTER_LZMA1, prefixes struct.pack('<BBH', 9, 4, len(props)) + props, and LZMADecompressor buffers input until the property-size header and properties are available, then uses a raw lzma.LZMADecompressor and exposes its eof state.
• 🟡 (15:09) /usr/lib/python3.12/zipfile/__init__.py:722-740 maps ZIP compression method IDs as: 0: 'store', 1: 'shrink', 2-5: 'reduce', 6: 'implode', 7: 'tokenize', 8: 'deflate', 9: 'deflate64', 10: 'implode', 12: 'bzip2', 14: 'lzma', 18: 'terse', 19: 'lz77', 97: 'wavpack', and 98: 'ppmd'.
• 🟡 (15:09) /usr/lib/python3.12/zipfile/__init__.py:742-792 supports ZIP_STORED, ZIP_DEFLATED, ZIP_BZIP2, and ZIP_LZMA; _check_compression() raises a missing-module RuntimeError for unavailable zlib, bz2, or lzma, and raises NotImplementedError("That compression method is not supported") for other methods. _get_decompressor() uses zlib.decompressobj(-15), bz2.BZ2Decompressor(), or LZMADecompressor() and reports recognized unsupported methods as NotImplementedError("compression type %d (%s)").
• 🟡 (15:09) /usr/lib/python3.12/zipfile/__init__.py:795-832 defines _SharedFile, whose seek() and read() serialize access with a lock, reject operations while a ZIP writing handle is open, seek the underlying file to _pos, and update _pos; close() clears its file reference before invoking the supplied close callback.