allow todos in user code to show in IDEs (#23303)

packages/flutter/lib/analysis_options_user.yaml

@@ -24,8 +24,6 @@ analyzer:
   errors:
     # treat missing required parameters as a warning (not a hint)
     missing_required_param: warning
-    # allow having TODOs in the code
-    todo: ignore
 
 linter:
   rules:

packages/flutter_tools/lib/src/commands/analyze_once.dart

@@ -87,7 +87,8 @@ class AnalyzeOnce extends AnalyzeBase {
       }
     });
     server.onErrors.listen((FileAnalysisErrors fileErrors) {
-      errors.addAll(fileErrors.errors);
+      // Record the issues found (but filter out to do comments).
+      errors.addAll(fileErrors.errors.where((AnalysisError error) => error.type != 'TODO'));
     });
 
     await server.start();

packages/flutter_tools/test/commands/analyze_once_test.dart

@@ -178,6 +178,24 @@ StringBuffer bar = StringBuffer('baz');
         tryToDelete(tempDir);
       }
     });
+
+    testUsingContext('returns no issues for todo comments', () async {
+      const String contents = '''
+// TODO(foobar):
+StringBuffer bar = StringBuffer('baz');
+''';
+      final Directory tempDir = fs.systemTempDirectory.createTempSync('flutter_analyze_once_test_4.');
+      tempDir.childFile('main.dart').writeAsStringSync(contents);
+      try {
+        await runCommand(
+          command: AnalyzeCommand(workingDirectory: fs.directory(tempDir)),
+          arguments: <String>['analyze'],
+          statusTextContains: <String>['No issues found!'],
+        );
+      } finally {
+        tryToDelete(tempDir);
+      }
+    });
   });
 }