Prioritize analysis of files that import the changed file, or have an error or warning.

pkg/analyzer/test/src/dart/analysis/driver_test.dart

 // Copyright (c) 2016, 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 file.
 
 library analyzer.test.driver;
 
 import 'dart:async';
 import 'dart:convert';
 
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 2161 matching lines @@
     allResults.clear();
 
     // Remove a.dart, now b.dart should be reanalyzed and has an error.
     provider.deleteFile(a);
     driver.removeFile(a);
     await scheduler.waitForIdle();
     expect(allResults.singleWhere((r) => r.path == b).errors, hasLength(2));
     allResults.clear();
   }
 
+  test_results_order() async {
+    var a = _p('/test/lib/a.dart');
+    var b = _p('/test/lib/b.dart');
+    var c = _p('/test/lib/c.dart');
+    var d = _p('/test/lib/d.dart');
+    var e = _p('/test/lib/e.dart');
+    var f = _p('/test/lib/f.dart');
+    provider.newFile(
+        a,
+        r'''
+import 'd.dart';
+''');
+    provider.newFile(b, '');
+    provider.newFile(
+        c,
+        r'''
+import 'd.dart';
+''');
+    provider.newFile(
+        d,
+        r'''
+import 'b.dart';
+''');
+    provider.newFile(
+        e,
+        r'''
+export 'b.dart';
+''');
+    provider.newFile(
+        f,
+        r'''
+import 'e.dart';
+class F extends X {}
+''');
+
+    driver.addFile(a);
+    driver.addFile(b);
+    driver.addFile(c);
+    driver.addFile(d);
+    driver.addFile(e);
+    driver.addFile(f);
+    await scheduler.waitForIdle();
+
+    // The file f.dart has an error or warning.
+    // So, its analysis will have higher priority.
+    expect(driver.fsState.getFileForPath(f).hasErrorOrWarning, isTrue);
+
+    allResults.clear();
+
+    // Update a.dart with changing its API signature.
+    provider.updateFile(b, 'class A {}');
+    driver.changeFile(b);
+    await scheduler.waitForIdle();
+
+    List<String> analyzedPaths = allResults.map((r) => r.path).toList();
+
+    // The changed file must be the first.
+    expect(analyzedPaths[0], b);
+
+    // Then the file that imports the changed file.
+    expect(analyzedPaths[1], d);
+
+    // Then the file that has an error (even if it is unrelated).
+    expect(analyzedPaths[2], f);
+  }
+
   test_results_priority() async {
     String content = 'int f() => 42;';
     addTestFile(content, priority: true);
 
     await scheduler.waitForIdle();
 
     expect(allResults, hasLength(1));
     AnalysisResult result = allResults.single;
     expect(result.path, testFile);
     expect(result.uri.toString(), 'package:test/test.dart');
@@ skipping 208 matching lines @@
    * Return the [provider] specific path for the given Posix [path].
    */
   String _p(String path) => provider.convertPath(path);
 
   static String _md5(String content) {
     return hex.encode(md5.convert(UTF8.encode(content)).bytes);
   }
 }
 
 class _SourceMock extends TypedMock implements Source {}