all externals to act as build: false

lib/trace.js

@@ -257,14 +257,14 @@ Trace.prototype.getLoadRecord = function(canonical, excludeURLs, parentStack) {
       var metadata = {};
       return Promise.resolve(loader.locate({ name: normalized.replace(interpolationRegEx, '*'), metadata: metadata }))
       .then(function(address) {
+        if (address.substr(0, 8) != 'file:///')
+          metadata.build = false;
+
         // allow build: false trace opt-out
         if (metadata.build === false)
           return false;
 
         // glob the conditional interpolation variations from the filesystem
-        if (address.substr(0, 8) != 'file:///')
-          throw new Error('Error tracing ' + canonical + '. It is only possible to trace conditional interpolation for modules resolving to local file:/// URLs during the build.');
-
         var globIndex = address.indexOf('*');
         return asp(glob)(fromFileURL(address), { dot: true, nobrace: true, noglobstar: true, noext: true, nodir: true })
         .then(function(paths) {
@@ -332,6 +332,9 @@ Trace.prototype.getLoadRecord = function(canonical, excludeURLs, parentStack) {
     .then(function(address) {
       curHook = '';
 
+      if (address.substr(0, 8) != 'file:///')
+        load.metadata.build = false;
+
       // build: false build config - null load record
       if (load.metadata.build === false)
         return false;