add an assert for a whacky case that is not supposed to happen but biting me a while back when some other code was broken. This has been kicking around my tree for a while.

modules/libreg/xpcom/nsRegistry.cpp

@@ -712,6 +712,7 @@ NS_IMETHODIMP nsRegistry::GetStringUTF8( nsRegistryKey baseKey, const char *path
     {
         // Convert status.
         rv = regerr2nsresult( err );
+        NS_ASSERTION(NS_FAILED(rv), "returning success code on failure");
     }
 
    return rv;

xpcom/components/nsRegistry.cpp

@@ -712,6 +712,7 @@ NS_IMETHODIMP nsRegistry::GetStringUTF8( nsRegistryKey baseKey, const char *path
     {
         // Convert status.
         rv = regerr2nsresult( err );
+        NS_ASSERTION(NS_FAILED(rv), "returning success code on failure");
     }
 
    return rv;