Prevent crashing when a report template disappears (#505921).

If a report template is missing (renamed, moved, deleted, whatever)
while the report is still open, then the app will crash while reading
the books file. The options-generator will fail and cause subsequent
attempts to access the options to fail and crash. A couple checks for
the existence of options is all it takes. Also included a warning dialog.

BP


git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@16836 57a11ea4-9604-0410-9ed3-97b8803252fd

src/app-utils/options.scm

@@ -1464,7 +1464,9 @@
   ((options 'for-each-general) section-thunk option-thunk))
 
 (define (gnc:lookup-option options section name)
-  ((options 'lookup) section name))
+  (if options
+      ((options 'lookup) section name)
+      #f))
 
 (define (gnc:generate-restore-forms options options-string)
   ((options 'generate-restore-forms) options-string))

src/report/report-system/report.scm

@@ -356,15 +356,23 @@
 
 ;; This is the function that is called when saved reports are evaluated.
 (define (gnc:restore-report id template-name options)
-  (let ((r ((record-constructor <report>)
-            (gnc:report-template-name-to-id template-name) id options #t #t #f #f)))
-    (gnc-report-add r))
+  (if options
+      (let ((r ((record-constructor <report>)
+		(gnc:report-template-name-to-id template-name) id options #t #t #f #f)))
+	(gnc-report-add r))
+      (begin
+	(gnc-error-dialog '() (string-append "Report Failed! One of your previously opened reports has failed to open. The template on which it was based: " template-name ", was not found."))
+	#f))
   )
 
 (define (gnc:restore-report-by-guid id template-id template-name options)
-  (let ((r ((record-constructor <report>)
-            template-id id options #t #t #f #f)))
-    (gnc-report-add r))
+  (if options
+      (let ((r ((record-constructor <report>)
+		 template-id id options #t #t #f #f)))
+	 (gnc-report-add r))
+      (begin
+	(gnc-error-dialog '() (string-append "Report Failed! One of your previously opened reports has failed to open. The template on which it was based: " template-name ", was not found."))
+	#f))
   )
 
 (define (gnc:make-report-options template-name)