Bug 1492090 - Part 9: Use UTF-8 in module ThrowResolutionError. r=nbp

Differential Revision: https://phabricator.services.mozilla.com/D151453

js/src/tests/shell/script-file-name-utf8.js

@@ -165,6 +165,20 @@ function getLcovInfoScriptName(fileName) {
   return scriptFiles[0].substring(3);
 }
 
+// Return the file name from the error during module import.
+function moduleResolutionError(fileName) {
+  const a = parseModule(`import { x } from "b";`, fileName);
+  const ma = registerModule("a", a);
+  const b = parseModule(`export var y = 10;`);
+  const mb = registerModule("b", b);
+
+  try {
+    moduleLink(ma);
+  } catch (e) {
+    return e.fileName;
+  }
+}
+
 // Return the file name from the profiler stack.
 function geckoInterpProfilingStack(fileName) {
   enableGeckoProfilingWithSlowAssertions();
@@ -191,6 +205,7 @@ const testFunctions = [
   fromErrorStackAsmJS,
   fromErrorStackStreamingWasm,
   getBacktraceScriptName,
+  moduleResolutionError,
 ];
 
 if (isLcovEnabled()) {

js/src/vm/Modules.cpp

@@ -885,7 +885,12 @@ static void ThrowResolutionError(JSContext* cx, Handle<ModuleObject*> module,
   }
 
   RootedString filename(cx);
-  filename = JS_NewStringCopyZ(cx, module->script()->filename());
+  if (const char* chars = module->script()->filename()) {
+    filename =
+        JS_NewStringCopyUTF8Z(cx, JS::ConstUTF8CharsZ(chars, strlen(chars)));
+  } else {
+    filename = cx->names().empty;
+  }
   if (!filename) {
     return;
   }