Fix for surround-with linked edit positions.

R=brianwilkerson@google.com

Bug: https://github.com/dart-lang/sdk/issues/32106
Change-Id: Ia899171aa38dd1283b72cdd100a0f5b678e9b565
Reviewed-on: https://dart-review.googlesource.com/41420
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>

pkg/analysis_server/lib/src/services/correction/assist_internal.dart

@@ -62,8 +62,6 @@ class AssistProcessor {
 
   final List<Assist> assists = <Assist>[];
 
-  Position exitPosition = null;
-
   CorrectionUtils utils;
 
   AstNode node;
@@ -2575,7 +2573,6 @@ class AssistProcessor {
     }
     // prepare statement information
     Statement firstStatement = selectedStatements[0];
-    Statement lastStatement = selectedStatements[selectedStatements.length - 1];
     SourceRange statementsRange =
         utils.getLinesRangeStatements(selectedStatements);
     // prepare environment
@@ -2593,7 +2590,6 @@ class AssistProcessor {
             utils.replaceSourceRangeIndent(
                 statementsRange, indentOld, indentNew));
         builder.addSimpleInsertion(statementsRange.end, '$indentOld}$eol');
-        exitPosition = _newPosition(lastStatement.end);
       });
       _addAssistFromBuilder(changeBuilder, DartAssistKind.SURROUND_WITH_BLOCK);
     }
@@ -2950,10 +2946,6 @@ class AssistProcessor {
     return utils.getRangeText(range);
   }
 
-  Position _newPosition(int offset) {
-    return new Position(file, offset);
-  }
-
   Future<Null> _swapFlutterWidgets(
       InstanceCreationExpression exprGoingDown,
       InstanceCreationExpression exprGoingUp,

pkg/analysis_server/test/services/correction/assist_test.dart

@@ -5050,6 +5050,8 @@ main() {
 // end
 }
 ''');
+    _assertLinkedGroup(change.linkedEditGroups[0], ['condition);']);
+    _assertExitPosition('condition);');
   }
 
   test_surroundWith_for() async {
@@ -5072,6 +5074,11 @@ main() {
 // end
 }
 ''');
+    _assertLinkedGroup(change.linkedEditGroups[0], ['v =']);
+    _assertLinkedGroup(change.linkedEditGroups[1], ['init;']);
+    _assertLinkedGroup(change.linkedEditGroups[2], ['condition;']);
+    _assertLinkedGroup(change.linkedEditGroups[3], ['increment']);
+    _assertExitPosition('  }');
   }
 
   test_surroundWith_forIn() async {
@@ -5094,6 +5101,9 @@ main() {
 // end
 }
 ''');
+    _assertLinkedGroup(change.linkedEditGroups[0], ['item']);
+    _assertLinkedGroup(change.linkedEditGroups[1], ['iterable']);
+    _assertExitPosition('  }');
   }
 
   test_surroundWith_if() async {
@@ -5116,6 +5126,8 @@ main() {
 // end
 }
 ''');
+    _assertLinkedGroup(change.linkedEditGroups[0], ['condition']);
+    _assertExitPosition('  }');
   }
 
   test_surroundWith_tryCatch() async {
@@ -5140,6 +5152,10 @@ main() {
 // end
 }
 ''');
+    _assertLinkedGroup(change.linkedEditGroups[0], ['Exception']);
+    _assertLinkedGroup(change.linkedEditGroups[1], ['e) {']);
+    _assertLinkedGroup(change.linkedEditGroups[2], ['// TODO']);
+    _assertExitPosition('// TODO');
   }
 
   test_surroundWith_tryFinally() async {
@@ -5164,6 +5180,8 @@ main() {
 // end
 }
 ''');
+    _assertLinkedGroup(change.linkedEditGroups[0], ['// TODO']);
+    _assertExitPosition('// TODO');
   }
 
   test_surroundWith_while() async {
@@ -5186,6 +5204,15 @@ main() {
 // end
 }
 ''');
+    _assertLinkedGroup(change.linkedEditGroups[0], ['condition']);
+    _assertExitPosition('  }');
+  }
+
+  void _assertExitPosition(String after) {
+    Position exitPosition = change.selection;
+    expect(exitPosition, isNotNull);
+    expect(exitPosition.file, testFile);
+    expect(exitPosition.offset, resultCode.indexOf(after) + after.length);
   }
 
   /**

pkg/analyzer_plugin/lib/src/utilities/change_builder/change_builder_core.dart

@@ -3,6 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async';
+import 'dart:collection';
 import 'dart:math' as math;
 
 import 'package:analyzer/src/generated/source.dart';
@@ -30,6 +31,12 @@ class ChangeBuilderImpl implements ChangeBuilder {
   final Map<String, LinkedEditGroup> _linkedEditGroups =
       <String, LinkedEditGroup>{};
 
+  /**
+   * The set of [Position]s that belong to the current [EditBuilderImpl] and
+   * should not be updated in result of inserting this builder.
+   */
+  final Set<Position> _lockedPositions = new HashSet<Position>.identity();
+
   /**
    * Initialize a newly created change builder.
    */
@@ -86,7 +93,7 @@ class ChangeBuilderImpl implements ChangeBuilder {
    */
   void _updatePositions(int offset, int delta) {
     void _updatePosition(Position position) {
-      if (position.offset >= offset) {
+      if (position.offset >= offset && !_lockedPositions.contains(position)) {
         position.offset = position.offset + delta;
       }
     }
@@ -165,6 +172,7 @@ class EditBuilderImpl implements EditBuilder {
       int end = offset + _buffer.length;
       int length = end - start;
       Position position = new Position(fileEditBuilder.fileEdit.file, start);
+      fileEditBuilder.changeBuilder._lockedPositions.add(position);
       LinkedEditGroup group =
           fileEditBuilder.changeBuilder.getLinkedEditGroup(groupName);
       group.addPosition(position, length);
@@ -315,6 +323,7 @@ class FileEditBuilderImpl implements FileEditBuilder {
     fileEdit.add(edit);
     int delta = _editDelta(edit);
     changeBuilder._updatePositions(edit.offset + math.max(0, delta), delta);
+    changeBuilder._lockedPositions.clear();
     _captureSelection(builder, edit);
   }