[PATCH] email: Support Date fields with missing seconds.

[Andrew Whatson <whatson@tailcall.au>]

* email/email.scm (parse-email-headers): Extend the date-time parser to
match when seconds are missing, defaulting to "0".
* tests/email.scm ("Parse Date without seconds"): New test.
---
 email/email.scm | 12 +++++++++---
 tests/email.scm | 11 +++++++++++
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/email/email.scm b/email/email.scm
index 71f0718..0d51eef 100644
--- a/email/email.scm
+++ b/email/email.scm
@@ -1,6 +1,7 @@
 ;;; guile-email --- Guile email parser
 ;;; Copyright © 2018, 2019, 2020, 2021 Arun Isaac <arunisaac@systemreboot.net>
 ;;; Copyright © 2021 Mathieu Othacehe <othacehe@gnu.org>
+;;; Copyright © 2023 Andrew Whatson <whatson@tailcall.au>
 ;;;
 ;;; This file is part of guile-email.
 ;;;
@@ -1050,9 +1051,14 @@ list of header keys and values."
      (received-token . ,(match-lambda*
                           (`(received-token ,token) token)))
      (date-time . ,(lambda node
-                     (match-let
-                         ((`((day ,day) (month ,month) (year ,year)
-                             (hours ,hours) (minutes ,minutes) (seconds ,seconds) (zone . ,zone))
+                     (match-let*
+                         (;; Seconds are optional; provide a default
+                          ;; binding which will be shadowed by match.
+                          (seconds "0")
+                          ((('day day) ('month month) ('year year)
+                            ('hours hours) ('minutes minutes)
+                            . (or (('seconds seconds) ('zone . zone))
+                                  (('zone . zone))))
                            (flatten-and-filter
                             '(day month year hours minutes seconds zone)
                             node)))
diff --git a/tests/email.scm b/tests/email.scm
index a6d2b46..cf565ba 100644
--- a/tests/email.scm
+++ b/tests/email.scm
@@ -1,6 +1,7 @@
 ;;; guile-email --- Guile email parser
 ;;; Copyright © 2017 Ricardo Wurmus <rekado@elephly.net>
 ;;; Copyright © 2018, 2019, 2020, 2021 Arun Isaac <arunisaac@systemreboot.net>
+;;; Copyright © 2023 Andrew Whatson <whatson@tailcall.au>
 ;;;
 ;;; This file was adapted from guile-debbugs and is part of guile-email.
 ;;;
@@ -558,6 +559,16 @@ Content-Type: text/plain; charset=utf-8
                   (charset . "utf-8"))
     (content-transfer-encoding . 7bit)))
 
+(test-alist= "Parse Date without seconds"
+  (parse-email-headers
+   "Date: Tue, 22 Nov 94 17:52 GMT
+")
+  `((date . ,(make-date 0 0 52 17 22 11 1994 0))
+    (content-type (type . text)
+                  (subtype . plain)
+                  (charset . "utf-8"))
+    (content-transfer-encoding . 7bit)))
+
 \f
 ;;;
 ;;; Email addresses
-- 
2.38.1