templates: Handle missing input case.

It happens that some left-over checkout entries refer to removed inputs. In
that case, input will be #f, causing commit-hyperlink to fail with the
following error message:

In cuirass/http.scm:
   475:25  9 (url-handler _ _)
    193:3  8 (evaluation-html-page ((#:id . 5103) (# . 0) (# . 39) ?) ?)
In cuirass/templates.scm:
   612:14  7 (evaluation-build-table _ #:checkouts _ #:inputs _ # _ # ?)
In srfi/srfi-1.scm:
   586:17  6 (map1 (((#:commit . "3a3e9f2bb586e79a7931163f0191d?") ?)))
In cuirass/templates.scm:
   621:39  5 (_ _)
   584:15  4 (commit-hyperlink #f "3a3e9f2bb586e79a7931163f0191df615?")
In web/uri.scm:
   308:23  3 (string->uri _)
   278:14  2 (string->uri-reference _)
In unknown file:
           1 (regexp-exec #<regexp 7f3a76c05980> #f #<undefined> #<u?>)
In ice-9/boot-9.scm:
  1669:16  0 (raise-exception _ #:continuable? _)
In procedure regexp-exec: Wrong type argument in position 2 (expecting string): #f

* src/cuirass/templates.scm (evaluation-build-table): Do not call
"commit-hyperlink" if the matching input could not be found.

1 files changed, 6 insertions, 2 deletions

diff --git a/src/cuirass/templates.scm b/src/cuirass/templates.scm
index 58ef142..170cc84 100644
--- a/src/cuirass/templates.scm
+++ b/src/cuirass/templates.scm
@@ -617,8 +617,12 @@ evaluation."
                                          inputs))
                             (url   (assq-ref input #:url))
                             (commit (assq-ref checkout #:commit)))
-                       `(tr (td ,url)
-                            (td (code ,(commit-hyperlink url commit))))))
+                       ;; Some checkout entries may refer to removed
+                       ;; inputs.
+                       (if input
+                           `(tr (td ,url)
+                                (td (code ,(commit-hyperlink url commit))))
+                           '())))
                    checkouts)))
 
     (p (@ (class "lead"))