[ES6 modules] Return previous error when an instantiation is reattempt.

third_party/WebKit/Source/core/loader/modulescript/ModuleTreeLinker.cpp

Index: third_party/WebKit/Source/core/loader/modulescript/ModuleTreeLinker.cpp
diff --git a/third_party/WebKit/Source/core/loader/modulescript/ModuleTreeLinker.cpp b/third_party/WebKit/Source/core/loader/modulescript/ModuleTreeLinker.cpp
index 7f9213e213e24be7730548294b06b323f6672a0b..9e1440b1a3b7044ac27541de364ad7c911291db8 100644
--- a/third_party/WebKit/Source/core/loader/modulescript/ModuleTreeLinker.cpp
+++ b/third_party/WebKit/Source/core/loader/modulescript/ModuleTreeLinker.cpp
@@ -112,7 +112,7 @@ void ModuleTreeLinker::AdvanceState(State new_state) {
     registry_->ReleaseFinishedFetcher(this);
 
     // https://html.spec.whatwg.org/multipage/webappapis.html#internal-module-script-graph-fetching-procedure
-    // Step 8. Asynchronously complete this algorithm with descendants result.
+    // Step 9. Asynchronously complete this algorithm with descendants result.
     client_->NotifyModuleTreeLoadFinished(descendants_module_script_);
   }
 }
@@ -230,7 +230,7 @@ void ModuleTreeLinker::FetchDescendants() {
 
       // Abort this algorithm, and asynchronously complete it with null.
       // Note: The return variable for "internal module script graph fetching
-      // procedure" is descendants_module_script_ per Step 8.
+      // procedure" is descendants_module_script_ per Step 9.
       DCHECK(!descendants_module_script_);
       // Note: while we complete "fetch the descendants of a module script"
       //       algorithm here, we still need to continue to the rest of the
@@ -336,33 +336,51 @@ void ModuleTreeLinker::Instantiate() {
 
   // https://html.spec.whatwg.org/multipage/webappapis.html#internal-module-script-graph-fetching-procedure
 
-  // Step 5. Let record be result's module record.
-  ScriptModule record = module_script_->Record();
-
-  // Step 6. Let instantiationStatus be record.ModuleDeclarationInstantiation().
+  // Step 5. Let instantiationStatus be null.
   // Note: The |error| variable corresponds to spec variable
   // "instantiationStatus". If |error| is empty, it indicates successful
   // completion.
-  ScriptValue error = modulator_->InstantiateModule(record);
+  ScriptValue error;
+
+  // Step 6. If result's instantiation state is "errored",...
+  if (module_script_->InstantiationState() ==
+      ModuleInstantiationState::kErrored) {
+    // ... Set instantiationStatus to record.ModuleDeclarationInstantiation().
+    error = modulator_->GetInstantiationError(module_script_);
+    DCHECK(!error.IsEmpty());
+  } else {
+    // Step 7. Otherwise:
+    // Step 7.1. Let record be result's module record.
+    ScriptModule record = module_script_->Record();
+    // Step 7.2. Set instantiationStatus to
+    // record.ModuleDeclarationInstantiation().
+    error = modulator_->InstantiateModule(record);
+  }
 
-  // Step 7. For each module script script in result's uninstantiated inclusive
+  // Step 8. For each module script script in result's uninstantiated inclusive
   // descendant module scripts, perform the following steps:
   HeapHashSet<Member<ModuleScript>> uninstantiated_set =
       UninstantiatedInclusiveDescendants();
   for (const auto& descendant : uninstantiated_set) {
     if (!error.IsEmpty()) {
-      // Step 7.1. If instantiationStatus is an abrupt completion, then set
-      // script's instantiation state to "errored", its instantiation error to
-      // instantiationStatus.[[Value]], and its module record to null.
+      // Step 8.1. If instantiationStatus is an abrupt completion, then
+      // Step 8.1.1. Set script module record's [[HostDefined]] field to
+      // undefined.
+      // TODO(kouhei): Implement this.
+
+      // Step 8.1.2. Set script's module record to null.
+      // Step 8.1.3. Set script's instantiation state to "errored".
+      // Step 8.1.4. Set script's instantiation error to
+      // instantiationStatus.[[Value]].
       descendant->SetInstantiationErrorAndClearRecord(error);
     } else {
-      // Step 7.2. Otherwise, set script's instantiation state to
+      // Step 8.2. Otherwise, set script's instantiation state to
       // "instantiated".
       descendant->SetInstantiationSuccess();
     }
   }
 
-  // Step 8. Asynchronously complete this algorithm with descendants result.
+  // Step 9. Asynchronously complete this algorithm with descendants result.
   AdvanceState(State::kFinished);
 }