[CFE] Cleanup unused parts in uriToSource

Change-Id: Ie26fb25a0394999df1c681296ef96a90d51d8c13
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/120789
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Jens Johansen <jensj@google.com>

Author: jensjoha

pkg/front_end/lib/src/fasta/incremental_compiler.dart

@@ -249,8 +249,8 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
 
       bool removedDillBuilders = false;
       for (LibraryBuilder builder in notReusedLibraries) {
-        // TODO(jensj): What about parts in uriToSource?
-        CompilerContext.current.uriToSource.remove(builder.fileUri);
+        cleanupSourcesForBuilder(
+            builder, uriTranslator, CompilerContext.current.uriToSource);
         incrementalSerializer?.invalidate(builder.fileUri);
 
         LibraryBuilder dillBuilder =
@@ -446,6 +446,19 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
     });
   }
 
+  void cleanupSourcesForBuilder(LibraryBuilder builder,
+      UriTranslator uriTranslator, Map<Uri, Source> uriToSource,
+      [Map<Uri, Source> uriToSourceExtra]) {
+    uriToSource.remove(builder.fileUri);
+    uriToSourceExtra?.remove(builder.fileUri);
+    Library lib = builder.library;
+    for (LibraryPart part in lib.parts) {
+      Uri partFileUri = getPartFileUri(lib.fileUri, part, uriTranslator);
+      uriToSource.remove(partFileUri);
+      uriToSourceExtra?.remove(partFileUri);
+    }
+  }
+
   @override
   CoreTypes getCoreTypes() => userCode?.loader?.coreTypes;
 
@@ -710,8 +723,8 @@ class IncrementalCompiler implements IncrementalKernelGenerator {
         Library lib = builder.library;
         removedLibraries.add(lib);
         dillLoadedData.loader.builders.remove(uri);
-        CompilerContext.current.uriToSource.remove(uri);
-        uriToSource.remove(uri);
+        cleanupSourcesForBuilder(builder, uriTranslator,
+            CompilerContext.current.uriToSource, uriToSource);
         userBuilders?.remove(uri);
         removeLibraryFromRemainingComponentProblems(lib, uriTranslator);
 

pkg/front_end/testcases/incremental_initialize_from_dill/cleans_up_uritosource_non_package_part.yaml

@@ -0,0 +1,35 @@
+# Copyright (c) 2019, the Dart project authors. Please see the AUTHORS file
+# for details. All rights reserved. Use of this source code is governed by a
+# BSD-style license that can be found in the LICENSE.md file.
+
+# Compile an application with no packages and two libraries. Update the world
+# to now only include one library. The now no longer referenced library should
+# also have been removed from the uri to sources.
+
+type: newworld
+worlds:
+  - entry: main.dart
+    sources:
+      main.dart: |
+        import "b.dart";
+        main() { b(); }
+      b.dart: |
+        part 'c.dart';
+        b() {
+          c();
+        }
+      c.dart: |
+        part of 'b.dart';
+        c() {}
+    expectedLibraryCount: 2
+  - entry: main.dart
+    worldType: updated
+    invalidate:
+      - b.dart
+    expectInitializeFromDill: false
+    sources:
+      b.dart: |
+        b() {}
+    expectedLibraryCount: 2
+    uriToSourcesDoesntInclude:
+      - c.dart

pkg/front_end/testcases/incremental_initialize_from_dill/cleans_up_uritosource_non_package_unreferenced_libraries.yaml

@@ -14,7 +14,13 @@ worlds:
         import "b.dart";
         main() { b(); }
       b.dart: |
-        b() {}
+        part 'c.dart';
+        b() {
+          c();
+        }
+      c.dart: |
+        part of 'b.dart';
+        c() {}
     expectedLibraryCount: 2
   - entry: main.dart
     worldType: updated
@@ -27,6 +33,7 @@ worlds:
     expectedLibraryCount: 1
     uriToSourcesDoesntInclude:
       - b.dart
+      - c.dart
   - entry: main.dart
     worldType: updated
     invalidate:
@@ -38,3 +45,4 @@ worlds:
     expectedLibraryCount: 1
     uriToSourcesDoesntInclude:
       - b.dart
+      - c.dart