suggest after import prefix in part files - fixes #25023

[email protected]

Review URL: https://codereview.chromium.org/1514603002 .

pkg/analysis_server/lib/src/provisional/completion/dart/completion_dart.dart

@@ -91,6 +91,16 @@ abstract class DartCompletionRequest extends CompletionRequest {
    */
   Future<CompilationUnit> resolveDeclarationsInScope();
 
+  /**
+   * Return a [Future] that completes with a list of directives for the library
+   * in which in which the completion is occurring.
+   * The [Future] may return `null` if the library unit cannot be determined
+   * (e.g. unlinked part file).
+   * Any information obtained from [target] prior to calling this method
+   * should be discarded as it may have changed.
+   */
+  Future<List<Directive>> resolveDirectives();
+
   /**
    * Return a [Future] that completes when the element associated with
    * the given [expression] in the target compilation unit is available.

pkg/analysis_server/lib/src/services/completion/dart/completion_manager.dart

@@ -59,6 +59,14 @@ class DartCompletionManager implements CompletionContributor {
  */
 class DartCompletionRequestImpl extends CompletionRequestImpl
     implements DartCompletionRequest {
+  /**
+   * The source for the library containing the completion request.
+   * This may be different from the source in which the completion is requested
+   * if the completion is being requested in a part file.
+   * This may be `null` if the library for a part file cannot be determined.
+   */
+  Source _librarySource;
+
   /**
    * The cached completion target or `null` if not computed yet.
    */
@@ -93,7 +101,16 @@ class DartCompletionRequestImpl extends CompletionRequestImpl
       SearchEngine searchEngine,
       Source source,
       int offset)
-      : super(context, resourceProvider, searchEngine, source, offset);
+      : super(context, resourceProvider, searchEngine, source, offset) {
+    if (target.unit.directives.any((d) => d is PartOfDirective)) {
+      List<Source> libraries = context.getLibrariesContaining(source);
+      if (libraries.isNotEmpty) {
+        _librarySource = libraries[0];
+      }
+    } else {
+      _librarySource = source;
+    }
+  }
 
   @override
   Future<LibraryElement> get libraryElement async {
@@ -134,24 +151,16 @@ class DartCompletionRequestImpl extends CompletionRequestImpl
       return unit;
     }
 
-    // Determine the library source
-    Source librarySource;
-    if (unit.directives.any((d) => d is PartOfDirective)) {
-      List<Source> libraries = context.getLibrariesContaining(source);
-      if (libraries.isEmpty) {
-        return null;
-      }
-      librarySource = libraries[0];
-    } else {
-      librarySource = source;
+    // Gracefully degrade if librarySource cannot be determined
+    if (_librarySource == null) {
+      return null;
     }
 
     // Resolve declarations in the target unit
     CompilationUnit resolvedUnit =
-        await new AnalysisFutureHelper<CompilationUnit>(
-            context,
-            new LibrarySpecificUnit(librarySource, source),
-            RESOLVED_UNIT3).computeAsync();
+        await new AnalysisFutureHelper<CompilationUnit>(context,
+                new LibrarySpecificUnit(_librarySource, source), RESOLVED_UNIT3)
+            .computeAsync();
 
     // TODO(danrubel) determine if the underlying source has been modified
     // in a way that invalidates the completion request
@@ -168,39 +177,45 @@ class DartCompletionRequestImpl extends CompletionRequestImpl
     return resolvedUnit;
   }
 
+  @override
+  Future<List<Directive>> resolveDirectives() async {
+    CompilationUnit libUnit;
+    if (_librarySource == source) {
+      libUnit = await resolveDeclarationsInScope();
+    } else if (_librarySource != null) {
+      libUnit =
+          await new AnalysisFutureHelper<CompilationUnit>(
+                  context,
+                  new LibrarySpecificUnit(_librarySource, _librarySource),
+                  RESOLVED_UNIT3)
+              .computeAsync();
+    }
+    return libUnit?.directives;
+  }
+
   @override
   Future resolveExpression(Expression expression) async {
     //TODO(danrubel) resolve the expression or containing method
     // rather than the entire complilation unit
 
-    CompilationUnit unit = target.unit;
-
-    // Determine the library source
-    Source librarySource;
-    if (unit.directives.any((d) => d is PartOfDirective)) {
-      List<Source> libraries = context.getLibrariesContaining(source);
-      if (libraries.isEmpty) {
-        return;
-      }
-      librarySource = libraries[0];
-    } else {
-      librarySource = source;
+    // Gracefully degrade if librarySource cannot be determined
+    if (_librarySource == null) {
+      return null;
     }
 
     // Resolve declarations in the target unit
     CompilationUnit resolvedUnit =
-        await new AnalysisFutureHelper<CompilationUnit>(
-            context,
-            new LibrarySpecificUnit(librarySource, source),
-            RESOLVED_UNIT).computeAsync();
+        await new AnalysisFutureHelper<CompilationUnit>(context,
+                new LibrarySpecificUnit(_librarySource, source), RESOLVED_UNIT)
+            .computeAsync();
 
     // TODO(danrubel) determine if the underlying source has been modified
     // in a way that invalidates the completion request
     // and return null
 
     // Gracefully degrade if unit cannot be resolved
     if (resolvedUnit == null) {
-      return;
+      return null;
     }
 
     // Recompute the target for the newly resolved unit

pkg/analysis_server/lib/src/services/completion/dart/library_member_contributor.dart

@@ -33,9 +33,10 @@ class LibraryMemberContributor extends DartCompletionContributor {
     // Resolve the expression and the containing library
     await request.resolveExpression(targetId);
     LibraryElement containingLibrary = await request.libraryElement;
-    // Gracefully degrade if the library could not be determined
+    List<Directive> directives = await request.resolveDirectives();
+    // Gracefully degrade if the library or directives could not be determined
     // e.g. detached part file or source change
-    if (containingLibrary == null) {
+    if (containingLibrary == null || directives == null) {
       return EMPTY_LIST;
     }
 
@@ -51,7 +52,7 @@ class LibraryMemberContributor extends DartCompletionContributor {
       List<CompletionSuggestion> suggestions = <CompletionSuggestion>[];
 
       // Find the import directive with the given prefix
-      for (Directive directive in request.target.unit.directives) {
+      for (Directive directive in directives) {
         if (directive is ImportDirective) {
           if (directive.prefix != null) {
             if (directive.prefix.name == elem.name) {

pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart

@@ -368,6 +368,9 @@ abstract class DartCompletionContributorTest extends AbstractContextTest {
     if (libraries.isNotEmpty) {
       return new Future.value(libraries);
     }
+    if (times == 0) {
+      fail('failed to determine libraries containing $testSource');
+    }
     context.performAnalysisTask();
     // We use a delayed future to allow microtask events to finish. The
     // Future.value or Future() constructors use scheduleMicrotask themselves and

pkg/analysis_server/test/services/completion/dart/library_member_contributor_test.dart

@@ -55,6 +55,23 @@ class LibraryMemberContributorTest extends DartCompletionContributorTest {
     assertSuggestFunction('loadLibrary', 'Future<dynamic>');
   }
 
+  test_libraryPrefix_deferred_inPart() async {
+    // SimpleIdentifier  PrefixedIdentifier  ExpressionStatement
+    var libFile = '${testFile.substring(0, testFile.length - 5)}A.dart';
+    addSource(
+        libFile,
+        '''
+        library testA;
+        import "dart:async" deferred as bar;
+        part "$testFile";''');
+    addTestSource('part of testA; foo() {bar.^}');
+    // Assume that libraries containing has been computed for part files
+    await computeLibrariesContaining();
+    await computeSuggestions();
+    assertSuggestClass('Future');
+    assertSuggestFunction('loadLibrary', 'Future<dynamic>');
+  }
+
   test_libraryPrefix_with_exports() async {
     addSource('/libA.dart', 'library libA; class A { }');
     addSource('/libB.dart', 'library libB; export "/libA.dart"; class B { }');
@@ -91,6 +108,42 @@ class LibraryMemberContributorTest extends DartCompletionContributorTest {
     assertNotSuggested('==');
   }
 
+  test_PrefixedIdentifier_library_inPart() async {
+    // SimpleIdentifier  PrefixedIdentifier  ExpressionStatement
+    var libFile = '${testFile.substring(0, testFile.length - 5)}A.dart';
+    addSource(
+        '/testB.dart',
+        '''
+        lib B;
+        var T1;
+        class X { }
+        class Y { }''');
+    addSource(
+        libFile,
+        '''
+        library testA;
+        import "/testB.dart" as b;
+        part "$testFile";
+        var T2;
+        class A { }''');
+    addTestSource('''
+        part of testA;
+        main() {b.^}''');
+    // Assume that libraries containing has been computed for part files
+    await computeLibrariesContaining();
+    await computeSuggestions();
+    expect(replacementOffset, completionOffset);
+    expect(replacementLength, 0);
+    assertSuggestClass('X');
+    assertSuggestClass('Y');
+    assertSuggestTopLevelVar('T1', null);
+    assertNotSuggested('T2');
+    assertNotSuggested('Object');
+    assertNotSuggested('b');
+    assertNotSuggested('A');
+    assertNotSuggested('==');
+  }
+
   test_PrefixedIdentifier_library_typesOnly() async {
     // SimpleIdentifier  PrefixedIdentifier  TypeName
     addSource(