[JSC] removeEntry() and clearAll() keep the realm's [[LoadedModules]] in step with the registry

Source/JavaScriptCore/runtime/JSMicrotask.cpp

@@ -1192,6 +1192,7 @@ static void moduleLoadTopSettled(JSGlobalObject* globalObject, VM& vm, ThrowScop
         }
 #if USE(BUN_JSC_ADDITIONS)
         }
+        context->setEntry(vm, context->loader()->getRegisteredMayBeNull(specifier, type));
 #endif
 
         JSPromise* statePromise = JSPromise::create(vm, globalObject->promiseStructure());
@@ -1262,6 +1263,16 @@ static void moduleLoadTopSettled(JSGlobalObject* globalObject, VM& vm, ThrowScop
     }
 }
 
+#if USE(BUN_JSC_ADDITIONS)
+// A load that failed before it had an entry has not lost one to removeEntry() or clearAll().
+static ModuleRegistryEntry* entryOfLoad(ModuleLoadingContext* context, const Identifier& specifier, ScriptFetchParameters::Type type)
+{
+    if (ModuleRegistryEntry* entry = context->entry())
+        return entry;
+    return context->loader()->getRegisteredMayBeNull(specifier, type);
+}
+#endif
+
 static void moduleLoadTopRejected(JSGlobalObject* globalObject, VM& vm, std::span<const JSValue, maxMicrotaskArguments> arguments, uint8_t payload)
 {
     // loadModule first overload: onLoadRejected
@@ -1278,7 +1289,11 @@ static void moduleLoadTopRejected(JSGlobalObject* globalObject, VM& vm, std::spa
         auto type = context->moduleRequest().type();
         // https://html.spec.whatwg.org/multipage/webappapis.html#fetch-a-single-module-script step 13.1
         // Only set an error if the entry already exists.
+#if USE(BUN_JSC_ADDITIONS)
+        if (ModuleRegistryEntry* entry = entryOfLoad(context, specifier, type))
+#else
         if (ModuleRegistryEntry* entry = context->loader()->getRegisteredMayBeNull(specifier, type))
+#endif
             entry->setEvaluationError(globalObject, arguments[1]);
         resultPromise->reject(vm, arguments[1]);
     }
@@ -1433,7 +1448,11 @@ static void moduleLoadStoreError(JSGlobalObject* globalObject, std::span<const J
         auto type = context->moduleRequest().type();
         // https://html.spec.whatwg.org/multipage/webappapis.html#fetch-a-single-module-script step 13.1
         // Only set an error if the entry already exists.
+#if USE(BUN_JSC_ADDITIONS)
+        ModuleRegistryEntry* entry = entryOfLoad(context, specifier, type);
+#else
         ModuleRegistryEntry* entry = context->loader()->getRegisteredMayBeNull(specifier, type);
+#endif
         if (!entry)
             return;
         if (auto* error = dynamicDowncast<ErrorInstance>(errorValue)) {

Source/JavaScriptCore/runtime/JSModuleLoader.cpp

@@ -926,6 +926,9 @@ JSPromise* JSModuleLoader::loadModule(JSGlobalObject* globalObject, const Module
     RETURN_IF_EXCEPTION(scope, nullptr);
 
     auto* context = ModuleLoadingContext::create(vm, this, moduleRequest, WTF::move(scriptFetcher), flags);
+#if USE(BUN_JSC_ADDITIONS)
+    context->setEntry(vm, getRegisteredMayBeNull(moduleRequest.m_specifier, moduleRequest.type()));
+#endif
     JSPromise* resultPromise = JSPromise::create(vm, globalObject->promiseStructure());
     resultPromise->markAsHandled();
 
@@ -1060,7 +1063,17 @@ void JSModuleLoader::finishLoadingImportedModule(JSGlobalObject* globalObject, c
     auto scope = DECLARE_THROW_SCOPE(vm);
 
     // 1. If result is a normal completion, then
+#if USE(BUN_JSC_ADDITIONS)
+    // hostLoadImportedModule() reads the realm's [[LoadedModules]] as a cache of the registry, and removeEntry() and
+    // clearAll() purge the two together. A load that was in flight then ends here with a record the registry let go of.
+    auto isRegistered = [&](AbstractModuleRecord* record) {
+        ModuleRegistryEntry* entry = getRegisteredMayBeNull(record->moduleKey(), moduleRequest.type());
+        return entry && entry->record() == record;
+    };
+    if (auto* resultRecord = std::get_if<AbstractModuleRecord*>(&result); resultRecord && (referrer.getModule() || isRegistered(*resultRecord))) {
+#else
     if (auto* resultRecord = std::get_if<AbstractModuleRecord*>(&result)) {
+#endif
         JSCell* owner = nullptr;
 
         auto& loadedModules = [&] -> ModuleMap<AbstractModuleRecord::LoadedModuleRequest> & {

Source/JavaScriptCore/runtime/ModuleLoadingContext.h

@@ -70,6 +70,11 @@ class ModuleLoadingContext final : public JSCell {
     const AbstractModuleRecord::ModuleRequest& moduleRequest() const { return m_moduleRequest; }
     JSCell* payload() const { return m_payload.get(); }
     ModuleRegistryEntry* entry() const { return m_entry.get(); }
+#if USE(BUN_JSC_ADDITIONS)
+    // A loadModule() context has none until the load has one. What the load then stores, it stores there: removeEntry()
+    // and clearAll() can leave another load's entry, or none, under the key while this one is in flight.
+    void setEntry(VM& vm, ModuleRegistryEntry* entry) { m_entry.setMayBeNull(vm, this, entry); }
+#endif
     ScriptFetcher* scriptFetcher() const { return m_scriptFetcher.get(); }
     AbstractModuleRecord* module() const { return m_module.get(); }
     void module(VM& vm, AbstractModuleRecord* mod) { m_module.set(vm, this, mod); }