Bug 1263629 - Use promise module invisible to the debugger for the browser toolbox server. r=jryans

devtools/shared/Loader.jsm

@@ -26,7 +26,6 @@ this.EXPORTED_SYMBOLS = ["DevToolsLoader", "devtools", "BuiltinProvider",
 var loaderModules = {
   "Services": Object.create(Services),
   "toolkit/loader": Loader,
-  promise,
   PromiseDebugging,
   ChromeUtils,
   ThreadSafeChromeUtils,
@@ -82,19 +81,7 @@ XPCOMUtils.defineLazyGetter(loaderModules, "URL", () => {
   return sandbox.URL;
 });
 
-var sharedGlobalBlocklist = ["sdk/indexed-db"];
-
-/**
- * Used when the tools should be loaded from the Firefox package itself.
- * This is the default case.
- */
-function BuiltinProvider() {}
-BuiltinProvider.prototype = {
-  load: function() {
-    this.loader = new Loader.Loader({
-      id: "fx-devtools",
-      modules: loaderModules,
-      paths: {
+const loaderPaths = {
   // ⚠ DISCUSSION ON DEV-DEVELOPER-TOOLS REQUIRED BEFORE MODIFYING ⚠
   "": "resource://gre/modules/commonjs/",
   // ⚠ DISCUSSION ON DEV-DEVELOPER-TOOLS REQUIRED BEFORE MODIFYING ⚠
@@ -109,9 +96,43 @@ BuiltinProvider.prototype = {
   "source-map": "resource://devtools/shared/sourcemap/source-map.js",
   // ⚠ DISCUSSION ON DEV-DEVELOPER-TOOLS REQUIRED BEFORE MODIFYING ⚠
   // Allow access to xpcshell test items from the loader.
-        "xpcshell-test": "resource://test"
-        // ⚠ DISCUSSION ON DEV-DEVELOPER-TOOLS REQUIRED BEFORE MODIFYING ⚠
-      },
+  "xpcshell-test": "resource://test",
+};
+
+var sharedGlobalBlocklist = ["sdk/indexed-db"];
+
+/**
+ * Used when the tools should be loaded from the Firefox package itself.
+ * This is the default case.
+ */
+function BuiltinProvider() {}
+BuiltinProvider.prototype = {
+  load: function() {
+    // Copy generic paths and modules for this loader instance
+    let paths = {};
+    for (let path in loaderPaths) {
+      paths[path] = loaderPaths[path];
+    }
+    let modules = {};
+    for (let name in loaderModules) {
+      XPCOMUtils.defineLazyGetter(modules, name, (function (name) {
+        return loaderModules[name];
+      }).bind(null, name));
+    }
+    // When creating a Loader invisible to the Debugger, we have to ensure
+    // using only modules and not depend on any JSM. As everything that is
+    // not loaded with Loader isn't going to respect `invisibleToDebugger`.
+    // But we have to keep using Promise.jsm for other loader to prevent
+    // breaking unhandled promise rejection in tests.
+    if (this.invisibleToDebugger) {
+      paths["promise"] = "resource://gre/modules/Promise-backend.js";
+    } else {
+      modules["promise"] = promise;
+    }
+    this.loader = new Loader.Loader({
+      id: "fx-devtools",
+      modules,
+      paths,
       globals: this.globals,
       invisibleToDebugger: this.invisibleToDebugger,
       sharedGlobal: true,

devtools/shared/tests/unit/test_invisible_loader.js

@@ -27,6 +27,11 @@ function visible_loader() {
   } catch(e) {
     do_throw("debugger could not add visible value");
   }
+
+  // Check that for common loader used for tabs, promise modules is Promise.jsm
+  // Which is required to support unhandled promises rejection in mochitests
+  const promise = Cu.import("resource://gre/modules/Promise.jsm", {}).Promise;
+  do_check_eq(loader.require("promise"), promise);
 }
 
 function invisible_loader() {
@@ -43,4 +48,11 @@ function invisible_loader() {
   } catch(e) {
     do_check_true(true);
   }
+
+  // But for browser toolbox loader, promise is loaded as a regular modules out
+  // of Promise-backend.js, that to be invisible to the debugger and not step
+  // into it.
+  const promise = loader.require("promise");
+  const promiseModule = loader._provider.loader.modules["resource://gre/modules/Promise-backend.js"];
+  do_check_eq(promise, promiseModule.exports);
 }