GeezerVison

getallmatchingheaders() has returned an empty list for every input since Python 3.0 — it compares keys() entries, which are bare header names, against "name:". Its only user was the CGI handler, which was removed in 3.15, and run_cgi() had already stopped calling it in 3.10.

Deprecate it, with removal in 3.18. That is PEP 387's minimum window rather than the usual five years, on the grounds that the method has never worked and has had no callers for five releases — happy to push it out to 3.21 if you'd rather keep it in line with the other 3.16 deprecations.

Use email.message.Message.get_all() instead.

#153648

• Issue: Deprecate and remove http.client.HTTPMessage.getallmatchingheaders() #153648