cpython/Misc/NEWS.d/next/Library/2024-07-27-16-10-41.gh-issu...

:mod:`email` headers with embedded newlines are now quoted on output. The
:mod:`~email.generator` will now refuse to serialize (write) headers that
are unsafely folded or delimited; see
:attr:`~email.policy.Policy.verify_generated_headers`. (Contributed by Bas
Bloemsaat and Petr Viktorin in :gh:`121650`.)
gh-121650: Encode newlines in headers, and verify headers are sound (GH-122233) ## Encode header parts that contain newlines Per RFC 2047: > [...] these encoding schemes allow the > encoding of arbitrary octet values, mail readers that implement this > decoding should also ensure that display of the decoded data on the > recipient's terminal will not cause unwanted side-effects It seems that the "quoted-word" scheme is a valid way to include a newline character in a header value, just like we already allow undecodable bytes or control characters. They do need to be properly quoted when serialized to text, though. ## Verify that email headers are well-formed This should fail for custom fold() implementations that aren't careful about newlines. Co-authored-by: Bas Bloemsaat <bas@bloemsaat.org> Co-authored-by: Serhiy Storchaka <storchaka@gmail.com> 2024-07-30 19:19:48 -03:00			:mod:`email` headers with embedded newlines are now quoted on output. The
			:mod:`~email.generator` will now refuse to serialize (write) headers that
			`are unsafely folded or delimited; see`
			:attr:`~email.policy.Policy.verify_generated_headers`. (Contributed by Bas
			Bloemsaat and Petr Viktorin in :gh:`121650`.)