view: Handle bugs without subjects gracefully.

* mumi/messages.scm (subject): Always return a string.
* mumi/web/view/html.scm (bug-subject*): New procedure.
(issue-page, list-of-bugs): Use it.

2 files changed, 11 insertions, 10 deletions

diff --git a/mumi/messages.scm b/mumi/messages.scm
index 63534a0..9409f34 100644
--- a/mumi/messages.scm
+++ b/mumi/messages.scm
@@ -78,7 +78,7 @@ yet.  Return new results alongside cached results."
   (header message 'date))
 
 (define-public (subject message)
-  (header message 'subject))
+  (or (header message 'subject) "(no subject)"))
 
 (define-public (message-id message)
   (header message 'message-id))
diff --git a/mumi/web/view/html.scm b/mumi/web/view/html.scm
index 8804213..ea05a34 100644
--- a/mumi/web/view/html.scm
+++ b/mumi/web/view/html.scm
@@ -34,6 +34,9 @@
             list-of-bugs
             priority-bugs))
 
+(define (bug-subject* bug)
+  (or (bug-subject bug) "(no subject)"))
+
 (define (status-tag bug)
   "Return a colored tag indicating the BUG status."
   (let ((status (if (bug-done bug) "Done" "Open")))
@@ -292,9 +295,7 @@ range.  The supported arguments are the same as for "
                  (a (@ (href ,(string-append "#" (number->string
                                                   message-number))))
                     ,(date->string (date message)))))
-          ,@(if (or (string-suffix? (or previous-subject "")
-                                    (or (subject message) ""))
-                    (not (subject message)))
+          ,@(if (string-suffix? previous-subject (subject message))
                 '()
                 `((div (@ (class "subject")) ,(subject message))))
           (div
@@ -320,7 +321,7 @@ range.  The supported arguments are the same as for "
                 (div (@ (class "label label-primary closed")) "Closed"))))
             '())))
   (layout
-   #:title (bug-subject bug)
+   #:title (bug-subject* bug)
    #:extra-headers
    (cond
     ((bug-archived bug)
@@ -336,7 +337,7 @@ range.  The supported arguments are the same as for "
       (@ (class "container"))
       (div
        (@ (class "row title col-md-12"))
-       (h1 ,(bug-subject bug))
+       (h1 ,(bug-subject* bug))
        (span (@ (class "details"))
              ,(status-tag bug)
              ,(string-append "Submitted by "
@@ -407,7 +408,7 @@ range.  The supported arguments are the same as for "
                   (show-message message-number msg previous-subject))
                 (iota (length msgs))
                 msgs
-                (cons (bug-subject bug)
+                (cons (bug-subject* bug)
                       (map subject msgs))))
         (div
          (@ (class "row comment-box"))
@@ -429,7 +430,7 @@ range.  The supported arguments are the same as for "
 supported.  To comment on this conversation "
                (a (@ (href ,(string-append "mailto:"
                                            (number->string id) "@" (%config 'debbugs-domain)
-                                           "?subject=" (bug-subject bug))))
+                                           "?subject=" (bug-subject* bug))))
                   ,(string-append "send email to "
                                   (number->string id) "@" (%config 'debbugs-domain)))))))))
 
@@ -478,8 +479,8 @@ supported.  To comment on this conversation "
                             (td ,(or id "-"))
                             (td ,(if id
                                      `(a (@ (href ,(string-append "/issue/" id)))
-                                         ,(bug-subject bug))
-                                     (bug-subject bug)))
+                                         ,(bug-subject* bug))
+                                     (bug-subject* bug)))
                             (td ,(date->string (bug-date bug)))
                             (td ,(status-tag bug)))))
                       bugs)))))