Save Changes Bug 776517 - Trial Balance Report:...

Total Debits Issue re $0 Commodity Accounts and Price Source Mode Set to
"Nearest in Time" or "Most Recent"

There was a silent error from gnc-numeric-sub-fixed in
collect-unrealized-gains because a 0 value wasn't getting its
denominator set in the gnc-numeric-mul call in
gnc:exchange-by-pricedb-helper. While this is ultimately a flaw in
gnc-numeric, this commit works around it by forcing the value to the
correct denom in gnc:make-commodity-collector.

src/report/report-system/report-utilities.scm

@@ -332,15 +332,18 @@
     ;; If no pair with this commodity exists, we will create one.
     (define (add-commodity-value commodity value)
       ;; lookup the corresponding pair
-      (let ((pair (assoc commodity commoditylist)))
+      (let ((pair (assoc commodity commoditylist))
+            (rvalue (gnc-numeric-convert
+                     value
+                     (gnc-commodity-get-fraction commodity) GNC-RND-ROUND)))
 	(if (not pair)
 	    (begin
 	      ;; create a new pair, using the gnc:numeric-collector
 	      (set! pair (list commodity (gnc:make-numeric-collector)))
 	      ;; and add it to the alist
 	      (set! commoditylist (cons pair commoditylist))))
 	;; add the value
-	(gnc:numeric-collector-add (cadr pair) value)))
+	(gnc:numeric-collector-add (cadr pair) rvalue)))
 
     ;; helper function to walk an association list, adding each
     ;; (commodity -> collector) pair to our list at the appropriate