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

pkg/analyzer/lib/src/dart/analysis/file_tracker.dart

 // Copyright (c) 2017, 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.
 
 import 'dart:collection';
 import 'dart:typed_data';
 
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/src/dart/analysis/byte_store.dart';
 import 'package:analyzer/src/dart/analysis/driver.dart';
@@ skipping 43 matching lines @@
 
   /**
    * The set of files were reported as changed through [changeFile] and not
    * checked for actual changes yet.
    */
   final _changedFiles = new LinkedHashSet<String>();
 
   /**
    * The set of files that are currently scheduled for analysis.
    */
-  final _pendingFiles = new LinkedHashSet<String>();
+  var _pendingFiles = new LinkedHashSet<String>();
 
   FileTracker(
       this.logger,
       ByteStore byteStore,
       FileContentOverlay contentOverlay,
       ResourceProvider resourceProvider,
       SourceFactory sourceFactory,
       AnalysisOptions analysisOptions,
       Uint32List salt,
       this._changeHook)
@@ skipping 90 matching lines @@
       List<FileState> files = fsState.getFilesForPath(path);
       for (FileState file in files) {
         bool apiChanged = file.refresh();
         if (apiChanged) {
           anyApiChanged = true;
         }
       }
       if (anyApiChanged) {
         logger.writeln('API signatures mismatch found for $path');
         // TODO(scheglov) schedule analysis of only affected files
-        _pendingFiles.addAll(addedFiles);
+        var pendingFiles = new LinkedHashSet<String>();
+
+        // Add the changed file.
+        if (addedFiles.contains(path)) {
+          pendingFiles.add(path);
+        }
+
+        // Add files that directly import the changed file.
+        for (String addedPath in addedFiles) {
+          FileState addedFile = fsState.getFileForPath(addedPath);
+          for (FileState changedFile in files) {
+            if (addedFile.importedFiles.contains(changedFile)) {
+              pendingFiles.add(addedPath);
+            }
+          }
+        }
+
+        // Add files with errors or warnings that might be fixed.
+        for (String addedPath in addedFiles) {
+          FileState addedFile = fsState.getFileForPath(addedPath);
+          if (addedFile.hasErrorOrWarning) {
+            pendingFiles.add(addedPath);
+          }
+        }
+
+        // Add all previous pending files.
+        pendingFiles.addAll(_pendingFiles);

[Brian Wilkerson, 2017/04/10 18:17:38]

Are we sure we want to add previous pending files after indirect files? If they
were explicitly changed it seems like they should be analyzed before files that
*might* be effected by changes.

[scheglov, 2017/04/10 18:51:58]

Well, we would need a way to distinguish which files in existing pending queue
were added there because the were changed, from the files that were added
because they might be affected to a previously changed file. Probably we would
need two separate buckets - for pending changed files, and all other pending
files (imports, errors, the rest). I don't know if it is worth.

+
+        // Add all the rest.
+        pendingFiles.addAll(addedFiles);
+
+        // Replace pending files.
+        _pendingFiles = pendingFiles;
       }
       return files[0];
     });
   }
 
   /**
    * If at least one file is in the "changed files" set, determines the impact
    * of the change, updates the set of pending files, and returns `true`.
    *
    * If no files are in the "changed files" set, returns `false`.
    */
   bool verifyChangedFilesIfNeeded() {
     // Verify all changed files one at a time.
     if (_changedFiles.isNotEmpty) {
       String path = _changedFiles.first;
       _changedFiles.remove(path);
       // If the file has not been accessed yet, we either will eventually read
       // it later while analyzing one of the added files, or don't need it.
       if (fsState.knownFilePaths.contains(path)) {
         verifyApiSignature(path);
       }
       return true;
     }
     return false;
   }
 }