Bug report

Bug description:

When streaming, writing to a zip file, it internally creates a ZipInfo object without explicitly setting date_time, causing a timestamp of 1980 to be used. I believe in almost all cases, using the current timestamp makes more sense, I rarely zip files from 1980. To work around that issue, Icreate the ZipInfo object myself and pass it to the open() method, which causes another bug where the specified compression is ignored and the file is simply stored.

After some minor investigation, I've found issue#113971 which at least hinted towards what I now use as workaround but otherwise didn't fix this:

Today people pass ZipInfo instances into APIs that accept them such as ZipFile.writestr() in order to control how individual items are put into a zip archive as such ...
zip_info.compress_type

So you'd create a new ZipFile specifying acompression but afteropen(), you're just storing uncompressed:

zip_info = zipfile.ZipInfo("file")# zip_info.compress_type, ._compresslevel are wrongzip_file.open(zip_info, mode="w", force_zip64=True)

In other words, I expect that:
a) when using open("file"...), it should use the current time as mtime by default
b) when creating a ZipInfo object to specify another date or another setting for the new file, it should inherit the previously configured compression
Both assumptions are wrong, which is what I'm suggesting to fix.

Here's a reproducer and I'll add a PR as suggested fix...
https://gist.github.com/c0xc/b54c005b296cdf6378ce65dd4aff3fe7

CPython versions tested on:

3.11, CPython main branch

Operating systems tested on:

Linux

Linked PRs

• gh-121402: Fix ZipFile.open() to set current time by default, add .newfile() #121405