zipimport.zipimporter breaks for zips containing files with size > 0xFFFFFFFF

[jsirois]

Bug report

Bug description:

The following test in the Pex project fails under CPython 3.13.0a6:
https://github.com/pex-tool/pex/blob/27c2db2bf26039bef41323c964bc4e0317a7b4f5/tests/test_pex_builder.py#L520-L547

The failure includes stderr output from zipimporter like:

Failed checking if argv[0] is an import path entry
Traceback (most recent call last):
  File "<frozen zipimport>", line 98, in __init__
  File "<frozen zipimport>", line 520, in _read_directory
NameError: name 'struct' is not defined. Did you forget to import 'struct'?
  File "/tmp/pytest-of-jsirois/pytest-14/test_check0/too-big.pyz", line 1
    PK-
SyntaxError: source code cannot contain null bytes

Inspection of #94146 indicates the code added to handle too large files is missing an import: https://github.com/python/cpython/pull/94146/files#r1572552939 The tests added in that PR do stress too many files for a 32 bit zip, but they do not stress too big a file for a 32 bit zip; so it makes sense that this import omission slipped past.

CPython versions tested on:

3.13, CPython main branch

Operating systems tested on:

Linux

Linked PRs

• gh-118107: Fix zipimporter ZIP64 handling. #118108

[encukou]

Marking as potential release blocker.

[encukou]

Thank you for the report and fix!