Bug 1789543 - Part 3: Trigger missing chrome/resource URL error handling with original JSM URL when fallback to ESMified URL also fails. r=yulia

Depends on D156763

Differential Revision: https://phabricator.services.mozilla.com/D156764

js/xpconnect/loader/ComponentModuleLoader.h

@@ -10,6 +10,8 @@
 #include "js/loader/LoadContextBase.h"
 #include "js/loader/ModuleLoaderBase.h"
 
+#include "SkipCheckForBrokenURLOrZeroSized.h"
+
 class mozJSModuleLoader;
 
 namespace mozilla {
@@ -103,6 +105,8 @@ class ComponentLoadContext : public JS::loader::LoadContextBase {
   // before being passed to the module loader.
   nsresult mRv;
 
+  SkipCheckForBrokenURLOrZeroSized mSkipCheck;
+
   // The exception thrown during compiling a module script. These fields are
   // used temporarily before being passed to the module loader.
   JS::PersistentRooted<JS::Value> mExceptionValue;

js/xpconnect/loader/SkipCheckForBrokenURLOrZeroSized.h

@@ -0,0 +1,22 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_loader_SkipCheckForBrokenURLOrZeroSized_h
+#define mozilla_loader_SkipCheckForBrokenURLOrZeroSized_h
+
+#include <stdint.h>  // uint8_t
+
+namespace mozilla {
+namespace loader {
+
+// Represents the `aSkipCheckForBrokenURLOrZeroSized` parameter for
+// `NS_NewChannel` function.
+enum class SkipCheckForBrokenURLOrZeroSized : uint8_t { No, Yes };
+
+}  // namespace loader
+}  // namespace mozilla
+
+#endif  // mozilla_loader_SkipCheckForBrokenURLOrZeroSized_h

js/xpconnect/loader/moz.build

@@ -45,6 +45,7 @@ EXPORTS.mozilla.loader += [
     "AutoMemMap.h",
     "ComponentModuleLoader.h",
     "ScriptCacheActors.h",
+    "SkipCheckForBrokenURLOrZeroSized.h",
 ]
 
 EXTRA_JS_MODULES += [

js/xpconnect/loader/mozJSModuleLoader.cpp

@@ -289,10 +289,25 @@ mozJSModuleLoader::mozJSModuleLoader()
 
 class MOZ_STACK_CLASS ModuleLoaderInfo {
  public:
-  explicit ModuleLoaderInfo(const nsACString& aLocation)
+  explicit ModuleLoaderInfo(const nsACString& aLocation,
-      : mLocation(&aLocation), mIsModule(false) {}
+                            SkipCheckForBrokenURLOrZeroSized aSkipCheck =
+                                SkipCheckForBrokenURLOrZeroSized::No)
+      : mLocation(&aLocation), mIsModule(false), mSkipCheck(aSkipCheck) {}
   explicit ModuleLoaderInfo(JS::loader::ModuleLoadRequest* aRequest)
-      : mLocation(nullptr), mURI(aRequest->mURI), mIsModule(true) {}
+      : mLocation(nullptr),
+        mURI(aRequest->mURI),
+        mIsModule(true),
+        mSkipCheck(aRequest->GetComponentLoadContext()->mSkipCheck) {}
+
+  SkipCheckForBrokenURLOrZeroSized getSkipCheckForBrokenURLOrZeroSized() const {
+    return mSkipCheck;
+  }
+
+  void resetChannelWithCheckForBrokenURLOrZeroSized() {
+    MOZ_ASSERT(mSkipCheck == SkipCheckForBrokenURLOrZeroSized::Yes);
+    mSkipCheck = SkipCheckForBrokenURLOrZeroSized::No;
+    mScriptChannel = nullptr;
+  }
 
   nsIIOService* IOService() {
     MOZ_ASSERT(mIOService);
@@ -325,14 +340,7 @@ class MOZ_STACK_CLASS ModuleLoaderInfo {
   nsresult EnsureScriptChannel() {
     BEGIN_ENSURE(ScriptChannel, IOService, URI);
 
-    // The JSM may already be ESM-ified, and in that case the load is expected
+    // Skip check for missing URL when handling JSM-to-ESM fallback.
-    // to fail.  Suppress the error message, the crash, and also the telemetry
-    // event for the failure.
-    //
-    // If this load fails, it will be redirected to `.sys.mjs` URL
-    // in TryFallbackToImportESModule, and the check is performed there.
-    bool skipCheckForBrokenURLOrZeroSized = !IsModule();
-
     return NS_NewChannel(
         getter_AddRefs(mScriptChannel), mURI,
         nsContentUtils::GetSystemPrincipal(),
@@ -342,7 +350,7 @@ class MOZ_STACK_CLASS ModuleLoaderInfo {
         /* aPerformanceStorage = */ nullptr,
         /* aLoadGroup = */ nullptr, /* aCallbacks = */ nullptr,
         nsIRequest::LOAD_NORMAL, mIOService, /* aSandboxFlags = */ 0,
-        skipCheckForBrokenURLOrZeroSized);
+        mSkipCheck == SkipCheckForBrokenURLOrZeroSized::Yes);
   }
 
   nsIURI* ResolvedURI() {
@@ -374,6 +382,7 @@ class MOZ_STACK_CLASS ModuleLoaderInfo {
   nsCOMPtr<nsIChannel> mScriptChannel;
   nsCOMPtr<nsIURI> mResolvedURI;
   const bool mIsModule;
+  SkipCheckForBrokenURLOrZeroSized mSkipCheck;
 };
 
 template <typename... Args>
@@ -1394,7 +1403,14 @@ nsresult mozJSModuleLoader::Import(JSContext* aCx, const nsACString& aLocation,
                     MarkerInnerWindowIdFromJSContext(aCx)),
       aLocation);
 
-  ModuleLoaderInfo info(aLocation);
+  // The JSM may already be ESM-ified, and in that case the load is expected
+  // to fail.  Suppress the error message, the crash, and also the telemetry
+  // event for the failure.
+  //
+  // If this load fails, it will be redirected to `.sys.mjs` URL
+  // in TryFallbackToImportESModule, and if the redirect also fails,
+  // the load is performed again below, with the check enabled.
+  ModuleLoaderInfo info(aLocation, SkipCheckForBrokenURLOrZeroSized::Yes);
 
   nsresult rv;
   ModuleEntry* mod;
@@ -1467,8 +1483,23 @@ nsresult mozJSModuleLoader::Import(JSContext* aCx, const nsACString& aLocation,
       }
 
       if (rv == NS_ERROR_FILE_NOT_FOUND) {
-        return TryFallbackToImportESModule(aCx, aLocation, aModuleGlobal,
+        rv = TryFallbackToImportESModule(aCx, aLocation, aModuleGlobal,
-                                           aModuleExports, aIgnoreExports);
+                                         aModuleExports, aIgnoreExports);
+
+        if (rv == NS_ERROR_FILE_NOT_FOUND) {
+          // Both JSM and ESM are not found, with the check inside necko
+          // skipped (See EnsureScriptChannel and mSkipCheck).
+          //
+          // Perform the load again with the check enabled, so that
+          // logging, crash-on-autonation, and telemetry event happen.
+          if (NS_SUCCEEDED(info.EnsureURI()) &&
+              !LocationIsRealFile(info.URI())) {
+            info.resetChannelWithCheckForBrokenURLOrZeroSized();
+            (void)ReadScript(info);
+          }
+        }
+
+        return rv;
       }
 
       // Something failed, but we don't know what it is, guess.
@@ -1526,7 +1557,10 @@ nsresult mozJSModuleLoader::TryFallbackToImportESModule(
   }
 
   JS::RootedObject moduleNamespace(aCx);
-  nsresult rv = ImportESModule(aCx, mjsLocation, &moduleNamespace);
+  // The fallback can fail if the URL was not for ESMified JSM.  Suppress the
+  // error message, the crash, and also the telemetry event for the failure.
+  nsresult rv = ImportESModule(aCx, mjsLocation, &moduleNamespace,
+                               SkipCheckForBrokenURLOrZeroSized::Yes);
   if (rv == NS_ERROR_FILE_NOT_FOUND) {
     // The error for ESModule shouldn't be exposed if the file does not exist.
     if (JS_IsExceptionPending(aCx)) {
@@ -1605,7 +1639,9 @@ nsresult mozJSModuleLoader::TryCachedFallbackToImportESModule(
 
 nsresult mozJSModuleLoader::ImportESModule(
     JSContext* aCx, const nsACString& aLocation,
-    JS::MutableHandleObject aModuleNamespace) {
+    JS::MutableHandleObject aModuleNamespace,
+    SkipCheckForBrokenURLOrZeroSized
+        aSkipCheck /* = SkipCheckForBrokenURLOrZeroSized::No */) {
   using namespace JS::loader;
 
   MOZ_ASSERT(mModuleLoader);
@@ -1643,6 +1679,7 @@ nsresult mozJSModuleLoader::ImportESModule(
       CORS_NONE, dom::ReferrerPolicy::No_referrer, principal);
 
   RefPtr<ComponentLoadContext> context = new ComponentLoadContext();
+  context->mSkipCheck = aSkipCheck;
 
   RefPtr<VisitedURLSet> visitedSet =
       ModuleLoadRequest::NewVisitedSetForTopLevelImport(uri);

js/xpconnect/loader/mozJSModuleLoader.h

@@ -18,6 +18,7 @@
 #include "nsClassHashtable.h"
 #include "jsapi.h"
 #include "js/experimental/JSStencil.h"
+#include "SkipCheckForBrokenURLOrZeroSized.h"
 
 #include "xpcpublic.h"
 
@@ -75,8 +76,11 @@ class mozJSModuleLoader final : public nsIMemoryReporter {
                   bool aIgnoreExports = false);
 
   // Load an ES6 module and all its dependencies.
-  nsresult ImportESModule(JSContext* aCx, const nsACString& aResourceURI,
+  nsresult ImportESModule(
-                          JS::MutableHandleObject aModuleNamespace);
+      JSContext* aCx, const nsACString& aResourceURI,
+      JS::MutableHandleObject aModuleNamespace,
+      mozilla::loader::SkipCheckForBrokenURLOrZeroSized aSkipCheck =
+          mozilla::loader::SkipCheckForBrokenURLOrZeroSized::No);
 
   // Fallback from Import to ImportESModule.
   nsresult TryFallbackToImportESModule(JSContext* aCx,