In #10972, I propose to add an option for the filename encoding to UTF-8. But I would like to force UTF-8 to create a ZIP file, it doesn't concern the decompression of a ZIP file.

Proposal of a specification to fix both issues at the same time.


"default_encoding" name is confusing because it doesn't specify if it is the encoding of (text?) file content or the encoding the filename. Why not simply "filename_encoding"?

The option can be added in multiple places:
 - argument to ZipFile constructor: this is needed to decompress
 - argument to ZipFile.write() and ZipInfo, because they are 3 different manners to add files

ZipFile.filename_encoding (and ZipInfo.filename_encoding) will be None by default: in this case, use the current algorithm (try cp437 or use UTF-8). Otherwise, use the encoding. If the encoding is UTF-8: set unicode flag.

Examples:
---
zipfile.ZipFile("non-ascii-cp932.zip", filename_encoding="cp932")

f = zipfile.ZipFile("test.zip", "w")
f.write(filename, filename_encoding="UTF-8")
info = ZipInfo(filename, filename_encoding="UTF-8")
f.writestr(info, b'data')
---

Don't add filename_encoding argument to ZipFile.writestr(), because it may conflict if a ZipInfo is passed and ZipInfo.filename_encoding and filename_encoding are different.