2 files changed, 29 insertions, 0 deletions
diff --git a/js/xpconnect/loader/mozJSModuleLoader.cpp b/js/xpconnect/loader/mozJSModuleLoader.cpp
index 017ac32b3b..cdf4df1970 100644
--- a/js/xpconnect/loader/mozJSModuleLoader.cpp
+++ b/js/xpconnect/loader/mozJSModuleLoader.cpp
@@ -1279,7 +1279,10 @@ nsresult mozJSModuleLoader::GetScriptForLocation(
 }
 
 void mozJSModuleLoader::UnloadModules() {
+  MOZ_ASSERT(!mIsUnloaded);
+
   mInitialized = false;
+  mIsUnloaded = true;
 
   if (mLoaderGlobal) {
     MOZ_ASSERT(JS_HasExtensibleLexicalEnvironment(mLoaderGlobal));
@@ -1387,6 +1390,11 @@ nsresult mozJSModuleLoader::IsModuleLoaded(const nsACString& aLocation,
                                            bool* retval) {
   MOZ_ASSERT(nsContentUtils::IsCallerChrome());
 
+  if (mIsUnloaded) {
+    *retval = false;
+    return NS_OK;
+  }
+
   mInitialized = true;
   ModuleLoaderInfo info(aLocation);
   if (mImports.Get(info.Key())) {
@@ -1420,6 +1428,11 @@ nsresult mozJSModuleLoader::IsJSModuleLoaded(const nsACString& aLocation,
                                              bool* retval) {
   MOZ_ASSERT(nsContentUtils::IsCallerChrome());
 
+  if (mIsUnloaded) {
+    *retval = false;
+    return NS_OK;
+  }
+
   mInitialized = true;
   ModuleLoaderInfo info(aLocation);
   if (mImports.Get(info.Key())) {
@@ -1435,6 +1448,11 @@ nsresult mozJSModuleLoader::IsESModuleLoaded(const nsACString& aLocation,
                                              bool* retval) {
   MOZ_ASSERT(nsContentUtils::IsCallerChrome());
 
+  if (mIsUnloaded) {
+    *retval = false;
+    return NS_OK;
+  }
+
   mInitialized = true;
   ModuleLoaderInfo info(aLocation);
 
@@ -1728,6 +1746,11 @@ nsresult mozJSModuleLoader::Import(JSContext* aCx, const nsACString& aLocation,
                                    JS::MutableHandleObject aModuleGlobal,
                                    JS::MutableHandleObject aModuleExports,
                                    bool aIgnoreExports) {
+  if (mIsUnloaded) {
+    JS_ReportErrorASCII(aCx, "Module loaded is already unloaded");
+    return NS_ERROR_FAILURE;
+  }
+
   mInitialized = true;
 
   AUTO_PROFILER_MARKER_TEXT(
@@ -2013,6 +2036,11 @@ nsresult mozJSModuleLoader::ImportESModule(
         aSkipCheck /* = SkipCheckForBrokenURLOrZeroSized::No */) {
   using namespace JS::loader;
 
+  if (mIsUnloaded) {
+    JS_ReportErrorASCII(aCx, "Module loaded is already unloaded");
+    return NS_ERROR_FAILURE;
+  }
+
   mInitialized = true;
 
   // Called from ChromeUtils::ImportESModule.
diff --git a/js/xpconnect/loader/mozJSModuleLoader.h b/js/xpconnect/loader/mozJSModuleLoader.h
index ac118c507d..b5e81a4b25 100644
--- a/js/xpconnect/loader/mozJSModuleLoader.h
+++ b/js/xpconnect/loader/mozJSModuleLoader.h
@@ -290,6 +290,7 @@ class mozJSModuleLoader final : public nsIMemoryReporter {
   nsClassHashtable<nsCStringHashKey, nsCString> mLocations;
 
   bool mInitialized;
+  bool mIsUnloaded = false;
 #ifdef DEBUG
   bool mIsInitializingLoaderGlobal = false;
 #endif