Fix `analyzer_cli` error overrides (#24452).

pkg/analyzer_cli/lib/src/analyzer_impl.dart

 // Copyright (c) 2015, 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_cli.src.analyzer_impl;
 
 import 'dart:collection';
 import 'dart:io';
 
 import 'package:analyzer/dart/element/element.dart';
+import 'package:analyzer/source/error_processor.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/java_engine.dart';
 import 'package:analyzer/src/generated/java_io.dart';
 import 'package:analyzer/src/generated/sdk_io.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/source_io.dart';
 import 'package:analyzer/src/generated/utilities_general.dart';
 import 'package:analyzer_cli/src/driver.dart';
 import 'package:analyzer_cli/src/error_formatter.dart';
@@ skipping 31 matching lines @@
   /// specified the "--package-warnings" option.
   String _selfPackageName;
 
   AnalyzerImpl(this.context, this.librarySource, this.options, this.startTime);
 
   /// Returns the maximal [ErrorSeverity] of the recorded errors.
   ErrorSeverity get maxErrorSeverity {
     var status = ErrorSeverity.NONE;
     for (AnalysisErrorInfo errorInfo in errorInfos) {
       for (AnalysisError error in errorInfo.errors) {
-        if (!_isDesiredError(error)) {
+        if (_processError(error) == null) {
           continue;
         }
         var severity = computeSeverity(error, options);
         status = status.max(severity);
       }
     }
     return status;
   }
 
   void addCompilationUnitSource(CompilationUnitElement unit,
@@ skipping 95 matching lines @@
     }
 
     // Compute max severity and set exitCode.
     ErrorSeverity status = maxErrorSeverity;
     if (status == ErrorSeverity.WARNING && options.warningsAreFatal) {
       status = ErrorSeverity.ERROR;
     }
     return status;
   }
 
-  bool _isDesiredError(AnalysisError error) {
-    if (error.errorCode.type == ErrorType.TODO) {
-      return false;
-    }
-    if (computeSeverity(error, options) == ErrorSeverity.INFO &&
-        options.disableHints) {
-      return false;
-    }
-    return true;
-  }
-
   /// Determine whether the given URI refers to a package other than the package
   /// being analyzed.
   bool _isOtherPackage(Uri uri) {
     if (uri.scheme != 'package') {
       return false;
     }
     if (_selfPackageName != null &&
         uri.pathSegments.length > 0 &&
         uri.pathSegments[0] == _selfPackageName) {
       return false;
@@ skipping 19 matching lines @@
   _printErrorsAndPerf() {
     // The following is a hack. We currently print out to stderr to ensure that
     // when in batch mode we print to stderr, this is because the prints from
     // batch are made to stderr. The reason that options.shouldBatch isn't used
     // is because when the argument flags are constructed in BatchRunner and
     // passed in from batch mode which removes the batch flag to prevent the
     // "cannot have the batch flag and source file" error message.
     StringSink sink = options.machineFormat ? errorSink : outSink;
 
     // Print errors.
-    ErrorFormatter formatter =
-        new ErrorFormatter(sink, options, _isDesiredError);
+    ErrorFormatter formatter = new ErrorFormatter(sink, options, _processError);
     formatter.formatErrors(errorInfos);
   }
 
+  /// Check various configuration options to get a desired severity for this
+  /// [error] (or `null` if it's to be suppressed).
+  ProcessedSeverity _processError(AnalysisError error) {
+    ErrorSeverity severity = computeSeverity(error, options, context);
+    bool isOverridden = false;
+
+    // First check for a filter.
+    if (severity == null) {
+      // Null severity means the error has been explicitly ignored.
+      return null;
+    } else {
+      isOverridden = true;
+    }
+
+    // If not overridden, some "natural" severities get globally filtered.
+    if (!isOverridden) {
+      // Check for global hint filtering.
+      if (severity == ErrorSeverity.INFO && options.disableHints) {
+        return null;
+      }
+
+      // Skip TODOs.
+      if (severity == ErrorType.TODO) {
+        return null;
+      }
+    }
+
+    return new ProcessedSeverity(severity, isOverridden);
+  }
+
   /// Compute the severity of the error; however:
   ///   * if [options.enableTypeChecks] is false, then de-escalate checked-mode
   ///   compile time errors to a severity of [ErrorSeverity.INFO].
   ///   * if [options.hintsAreFatal] is true, escalate hints to errors.
   static ErrorSeverity computeSeverity(
-      AnalysisError error, CommandLineOptions options) {
+      AnalysisError error, CommandLineOptions options,
+      [AnalysisContext context]) {
+    if (context != null) {
+      ErrorProcessor processor = ErrorProcessor.getProcessor(context, error);
+      // If there is a processor for this error, defer to it.
+      if (processor != null) {
+        return processor.severity;
+      }
+    }
+
     if (!options.enableTypeChecks &&
         error.errorCode.type == ErrorType.CHECKED_MODE_COMPILE_TIME_ERROR) {
       return ErrorSeverity.INFO;
     }
+
     if (options.hintsAreFatal && error.errorCode is HintCode) {
       return ErrorSeverity.ERROR;
     }
+
     return error.errorCode.errorSeverity;
   }
 
   /// Return the corresponding package directory or `null` if none is found.
   static JavaFile getPackageDirectoryFor(JavaFile sourceFile) {
     // We are going to ask parent file, so get absolute path.
     sourceFile = sourceFile.getAbsoluteFile();
     // Look in the containing directories.
     JavaFile dir = sourceFile.getParentFile();
     while (dir != null) {
@@ skipping 22 matching lines @@
   }
 
   @override
   void logInformation(String message, [CaughtException exception]) {
     outSink.writeln(message);
     if (exception != null) {
       outSink.writeln(exception);
     }
   }
 }