ZipFile.mkdir(ZipInfo.from_file(...)) CRC AttributeError

Bug report

Bug description:

Adding a directory entry to a zip file on the basis of a ZipInfo object (to pick up metadata) fails because ZipFile evidently expects the object to have a CRC attribute even though it's a directory rather than a file. I can work around this bug by storing the ZipInfo in a variable and giving it a nominal CRC (namely 0), but that shouldn't be necessary. Specifically,

import os
import zipfile
with zipfile.ZipFile("bug.zip", mode = "w") as z:
    os.chdir('/')
    z.mkdir(zipfile.ZipInfo.from_file('usr'))

fails:

  File ".../zipfile-bug.py", line 6, in <module>
    z.mkdir(zipfile.ZipInfo.from_file('usr'))
  File "/usr/lib/python3.12/zipfile/__init__.py", line 1935, in mkdir
    self.fp.write(zinfo.FileHeader(False))
                  ^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/zipfile/__init__.py", line 460, in FileHeader
    CRC = self.CRC
          ^^^^^^^^
AttributeError: 'ZipInfo' object has no attribute 'CRC'

Could you please take a look?

Thanks!

CPython versions tested on:

3.11, 3.12, 3.13

Operating systems tested on:

Linux

Linked PRs

• gh-119108

Start with Lib/zipfile/init.py, especially ZipFile.mkdir and ZipInfo.FileHeader, and reproduce the supplied ZipInfo.from_file('usr') example. Check the zipfile tests for directory entries and add coverage for this call; done means the example completes without AttributeError and the relevant tests pass.