Keep libraries after linking, don't reload from bytes.

Presubmit in google3 looks green.
https://test.corp.google.com/ui#id=OCL:376412203:BASE:379875911:1623903883365:2a59d852

Change-Id: I344d49fa12e2f07aa00623ea08e7530872ca2eec
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/201661
Reviewed-by: Samuel Rawlins <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>

Author: scheglov

pkg/analyzer/lib/src/dart/analysis/library_context.dart

@@ -183,21 +183,18 @@ class LibraryContext {
         counterUnlinkedLinkedBytes += resolutionBytes.length;
 
         librariesLinkedTimer.stop();
-        // TODO(scheglov) Uncomment to keep linking elements.
-        // return;
       } else {
         // TODO(scheglov) Take / clear parsed units in files.
         bytesGet += resolutionBytes.length;
         librariesLoaded += cycle.libraries.length;
+        elementFactory.addBundle(
+          BundleReader(
+            elementFactory: elementFactory,
+            unitsInformativeBytes: unitsInformativeBytes,
+            resolutionBytes: resolutionBytes,
+          ),
+        );
       }
-
-      elementFactory.addBundle(
-        BundleReader(
-          elementFactory: elementFactory,
-          unitsInformativeBytes: unitsInformativeBytes,
-          resolutionBytes: resolutionBytes,
-        ),
-      );
     }
 
     logger.run('Prepare linked bundles', () {

pkg/analyzer/lib/src/dart/micro/resolve_file.dart

@@ -908,17 +908,16 @@ class _LibraryContext {
       } else {
         performance.getDataInt('bytesGet').add(resolutionBytes.length);
         performance.getDataInt('libraryLoadCount').add(cycle.libraries.length);
+        elementFactory.addBundle(
+          BundleReader(
+            elementFactory: elementFactory,
+            unitsInformativeBytes: unitsInformativeBytes,
+            resolutionBytes: resolutionBytes as Uint8List,
+          ),
+        );
       }
       cycle.resolutionId = resolutionData!.id;
 
-      elementFactory.addBundle(
-        BundleReader(
-          elementFactory: elementFactory,
-          unitsInformativeBytes: unitsInformativeBytes,
-          resolutionBytes: resolutionBytes as Uint8List,
-        ),
-      );
-
       // We might have just linked dart:core, ensure the type provider.
       _createElementFactoryTypeProvider();
     }

pkg/analyzer/lib/src/summary2/link.dart

@@ -24,7 +24,6 @@ import 'package:analyzer/src/summary2/types_builder.dart';
 import 'package:analyzer/src/summary2/variance_builder.dart';
 
 var timerLinkingLinkingBundle = Stopwatch();
-var timerLinkingRemoveBundle = Stopwatch();
 
 /// Note that AST units and tokens of [inputLibraries] will be damaged.
 ///
@@ -81,13 +80,6 @@ class Linker {
     timerLinkingLinkingBundle.start();
     _writeLibraries();
     timerLinkingLinkingBundle.stop();
-
-    // TODO(scheglov) Remove to keep linking elements.
-    timerLinkingRemoveBundle.start();
-    elementFactory.removeBundle(
-      inputLibraries.map((e) => e.uriStr).toSet(),
-    );
-    timerLinkingRemoveBundle.stop();
   }
 
   void _buildEnumChildren() {

pkg/analyzer/test/src/summary/resynthesize_ast2_test.dart

@@ -26,7 +26,8 @@ import 'test_strategies.dart';
 
 main() {
   defineReflectiveSuite(() {
-    defineReflectiveTests(ResynthesizeAst2Test);
+    defineReflectiveTests(ResynthesizeAstKeepLinkingTest);
+    defineReflectiveTests(ResynthesizeAstFromBytesTest);
     // defineReflectiveTests(ApplyCheckElementTextReplacements);
   });
 }
@@ -39,11 +40,16 @@ class ApplyCheckElementTextReplacements {
 }
 
 @reflectiveTest
-class ResynthesizeAst2Test extends AbstractResynthesizeTest
+abstract class ResynthesizeAst2Test extends AbstractResynthesizeTest
     with ResynthesizeTestCases {
   /// The shared SDK bundle, computed once and shared among test invocations.
   static _SdkBundle? _sdkBundle;
 
+  /// We need to test both cases - when we keep linking libraries (happens for
+  /// new or invalidated libraries), and when we load libraries from bytes
+  /// (happens internally in Blaze or when we have cached summaries).
+  bool get keepLinkingLibraries;
+
   _SdkBundle get sdkBundle {
     if (_sdkBundle != null) {
       return _sdkBundle!;
@@ -124,14 +130,18 @@ class ResynthesizeAst2Test extends AbstractResynthesizeTest
 
     var linkResult = link(elementFactory, inputLibraries, true);
 
-    // TODO(scheglov) Remove to keep linking elements.
-    elementFactory.addBundle(
-      BundleReader(
-        elementFactory: elementFactory,
-        unitsInformativeBytes: unitsInformativeBytes,
-        resolutionBytes: linkResult.resolutionBytes,
-      ),
-    );
+    if (!keepLinkingLibraries) {
+      elementFactory.removeBundle(
+        inputLibraries.map((e) => e.uriStr).toSet(),
+      );
+      elementFactory.addBundle(
+        BundleReader(
+          elementFactory: elementFactory,
+          unitsInformativeBytes: unitsInformativeBytes,
+          resolutionBytes: linkResult.resolutionBytes,
+        ),
+      );
+    }
 
     return elementFactory.libraryOfUri('${source.uri}')!;
   }
@@ -232,6 +242,18 @@ class ResynthesizeAst2Test extends AbstractResynthesizeTest
   }
 }
 
+@reflectiveTest
+class ResynthesizeAstFromBytesTest extends ResynthesizeAst2Test {
+  @override
+  bool get keepLinkingLibraries => false;
+}
+
+@reflectiveTest
+class ResynthesizeAstKeepLinkingTest extends ResynthesizeAst2Test {
+  @override
+  bool get keepLinkingLibraries => true;
+}
+
 class _AnalysisSessionForLinking implements AnalysisSessionImpl {
   @override
   final ClassHierarchy classHierarchy = ClassHierarchy();