Convert os.altsep to '/' in filenames when creating ZipInfo objects

This causes the zipfile module to also consider the character defined by
`os.altsep` (if there is one) to be a path separator and convert it to a
forward slash, as defined by the zip specification.

Author: pR0Ps

Lib/zipfile/__init__.py

@@ -376,6 +376,8 @@ def __init__(self, filename="NoName", date_time=(1980,1,1,0,0,0)):
         # ZIP format specification.
         if os.sep != "/" and os.sep in filename:
             filename = filename.replace(os.sep, "/")
+        if os.altsep and os.altsep != "/" and os.altsep in filename:
+            filename = filename.replace(os.altsep, "/")
 
         self.filename = filename        # Normalized file name
         self.date_time = date_time      # year, month, day, hour, min, sec

Misc/NEWS.d/next/Library/2022-05-02-16-21-05.gh-issue-92184.hneGVW.rst

@@ -0,0 +1,2 @@
+When creating zip files using the ``zipfile`` module, ``os.altsep`` will always
+be treated as a path separator. Patch by Carey Metcalfe.