python / python/cpython

`lzma` module parity issues between platforms

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extension-modules OS-windows stdlib type-bug
Dominant language
Python
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Description

Bug report

Bug description:
file = bytes.fromhex("5d 00 00 00 01 1c 03 00 00 00 00 00 00 00 22 9e 0a 07 11 8f 47 b1 b9 0d 6f 94 20 29 e9 bd 75 36 2c fa d5 b3 21 74 52 ae e3 20 73 96 e5 c9 5c 38 fa a8 e5 74 22 47 9d 41 e1 6e 0b c3 62 25 4c c7 24 35 d6 10 4c ce db 51 a1 da 26 29 42 8d b2 1d 54 56 b2 5f 51 10 b8 bd e0 5a 6a 29 dd 95 63 b9 f4 bc 79 37 50 ed 61 2b ec 2c 8b 25 96 40 30 5b f5 f2 dc 28 f7 75 3b 7b dd cf 7a 81 8a af 81 81 aa 74 bb 01 e3 df 2d 84 7b 5e 84 38 89 c9 c3 ac cf 52 f2 11 71 89 55 58 61 43 1f a2 7e 39 e7 30 74 01 35 a8 1f 40 f7 d7 15 6e 32 b3 cb 0d 7e 71 07 dc 76 4f 51 af 72 f5 5f e4 3d 54 82 3e 11 29 b0 01 b9 ea a7 fb fe db 17 4b b3 6f 2b 95 0e 22 e2 ea 86 72 d0 0c 5b cb de bd 78 92 20 07 96 e0 8c 8b 7d 71 8d 41 d9 cd 1e 22 fb 35 b3 b8 72 a1 b3 a0 ee 60 d3 04 1b 53 f3 57 62 23 6d 47 3e 7d 49 81 7f a2 67 98 7d cc e8 19 d0 93 4c 43 23 60 27 ea 80 e3 bf 49 5b c6 19 63 63 87 54 d9 61 67 0c 14 bb bf 84 bb 31 55 d8 de d9 2d 48 30 b8 c8 9b 71 eb 0c 74 98 a2 93 23 f7 a9 29 a0 25 27 58 e6 48 fd db 77 ab e8 67 cf 55 41 ec f2 36 52 5d 87 60 ba fa 71 f3 e5 fc cd 8c 02 53 b8 bf cf e3 59 97 53 36 37 f5 7c 1b cd e9 8e 0e 59 7a 33 6b 32 63 f6 3f f7 25 fc 94 8f f3 be 1f dd 5d 9d c5 82 10 d9 a0 ac f2 cc b8 1c 09 b6 16 4c e8 36 61 ef a3 48 94 9f fa 42 ed 88 66 d8 4f da 8a fa 4a ff 15 c0 26 88 45 db ff f3 a1 34 cd f9 69 e5 cf 27 0d 6e 1b 65 2a c3 f9 4b 85 f7 3c 45 84 30 af 80 e9 38 34 dc 83 d7 b9 54 79 ea d6 17 3c 22 97 68 4e 72 fa d2 e7 03 b9 33 fd b1 ee 7c 79 48 01 0a 57 33 29 d1 2c fa 5b ff ff e1 40 2d dc")

import lzma
lzma.decompress(file)

The above code does not work on a fresh Python 3.12 install under Windows 10 and 11 (_lzma.LZMAError: Corrupt input data), it does however work on a self-built Python 3.12 on Debian Linux, and probably Linux in general. (I, myself, have tested on Win11, Win10 and self-built Debian, a few other users have on unspecified Linuxes and Windowses).

This difference between platforms is, as far as I know, not intentional (and if it is, this is not mentioned in the lzma module documentation).

(the raw data is sourced from https://origin.warframe.com/PublicExport/index_en.txt.lzma, (C) Digital Extremes, probably)

CPython versions tested on:

3.12

Operating systems tested on:

Linux, Windows

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the lzma.decompress(file) example on Python 3.12 under Windows 10 or 11 and on Debian Linux, using the provided hexadecimal data. Compare the platform behavior and the resulting LZMAError, then determine whether the difference should be corrected or documented; done means the platform discrepancy has a justified, tested resolution.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
operating-systems
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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