net/mail: avoid ParseDate confusion if day name includes "T"
Fixes the check for RFC 5322 "obsolete time zone" to ensure
that we correctly extract the entire date from the "T" of the
implied time zone.
Obsolete Time zones come in the form:
* GMT
* PST
* MDT
etc, as per Section 4.3 of RFC 5322,
https://tools.ietf.org/html/rfc5322#section-4.3.
The prior check from CL 117596 erronenously used strings.Index
which selects the first "T", and that meant that dates containing
days "Tue" or "Thu" could not be parsed.
We also now deal with "T" in the CFWS "Comment Folding White Space".
Thus we'll now accept dates:
* Thu, 20 Nov 1997 09:55:06 MDT
* Thu, 20 Nov 1997 09:55:06 MDT (MDT)
* Fri, 21 Nov 1997 09:55:06 MDT (This comment)
* Fri, 21 Nov 1997 09:55:06 MDT (MDT
Fixes #39260
Change-Id: I6d59d99bc4f05a82582c826b5c5a080a25fd999b
Reviewed-on: https://go-review.googlesource.com/c/go/+/235200
Run-TryBot: Emmanuel Odeke <emmanuel@orijtech.com>
TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
Trust: Emmanuel Odeke <emmanuel@orijtech.com>