`.pyc` file in zipapp can be marked as stale if opened in a different timezone than the one it was created in

Bug report

Bug description:

_get_mtime_and_size_of_source uses localtime rather than UTC --- in a zipapp, if the pyc was created in a timezone that is different than the timezone of the computer that it is being run on, it can be marked as 'stale', even though it shouldn't be --- for example, if the source file was last modified at 3:30 EST, that 3:30 EST will be stored in the pyc file as a Unix timestamp. However, if the zipapp is then transferred to a computer running PST, the modification time of the source file will be read from the zip file as 3:30 PST in unix time (through time.mktime), which will obviously be different than the 3:30 EST read from the pyc file directly (since it is never passed through time.mktime).

This seems to be because zip files do not store timezones with mtime, so Python is forced to interpret it as local time.

CPython versions tested on:

3.11, 3.13

Operating systems tested on:

Linux, macOS

Linked PRs

• gh-143868
• gh-143953

从 _get_mtime_and_size_of_source 开始，追踪 zipapp 源代码的 mtime 如何通过 time.mktime 转换，以及它与 pyc 时间戳的差异。在 Linux 或 macOS 上复现 Python 3.11 或 3.13 中所描述的时区差异，然后验证在时区之间传输的 pyc 不会再被错误地标记为过期。