Fix last column calculation in scanForLocalVariableLocations

runtime/observatory/lib/src/service/object.dart

 // Copyright (c) 2014, 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.
 
 part of service;
 
 /// An RpcException represents an exceptional event that happened
 /// while invoking an rpc.
 abstract class RpcException implements Exception {
   RpcException(this.message);
@@ skipping 2530 matching lines @@
 
     // Result.
     var r = <LocalVarLocation>[];
 
     // Limits.
     final lastLine = tokenToLine(endTokenPos);
     if (lastLine == null) {
       return r;
     }
 
-    final lastColumn = tokenToCol(endTokenPos);
+    var lastColumn = tokenToCol(endTokenPos);
     if (lastColumn == null) {
       return r;
     }
     // Current scan position.
     var line = tokenToLine(tokenPos);
     if (line == null) {
       return r;
     }
     var column = tokenToCol(tokenPos);
     if (column == null) {
       return r;
     }
 
     // Move back by name length.
     // TODO(johnmccutchan): Fix LocalVarDescriptor to set column before the
     // identifier name.
     column = math.max(0, column - name.length);
 
     var lineContents;
 
     if (line == lastLine) {
       // Only one line.
       if (!getLine(line).isTrivialLine) {
+        // TODO(johnmccutchan): end token pos -> column can lie for snapshotted
+        // code. e.g.:
+        // io_sink.dart source line 23 ends at column 39
+        // io_sink.dart snapshotted source line 23 ends at column 35.
+        lastColumn = math.min(getLine(line).text.length, lastColumn);
         lineContents = getLine(line).text.substring(column, lastColumn - 1);
         return scanLineForLocalVariableLocations(pattern,
                                                   name,
                                                   lineContents,
                                                   line,
                                                   column);
       }
     }
 
     // Scan first line.
@@ skipping 16 matching lines @@
       r.addAll(
           scanLineForLocalVariableLocations(pattern,
                                              name,
                                              lineContents,
                                              line++,
                                              0));
     }
 
     // Scan last line.
     if (!getLine(line).isTrivialLine) {
+      // TODO(johnmccutchan): end token pos -> column can lie for snapshotted
+      // code. e.g.:
+      // io_sink.dart source line 23 ends at column 39
+      // io_sink.dart snapshotted source line 23 ends at column 35.
+      lastColumn = math.min(getLine(line).text.length, lastColumn);
       lineContents = getLine(line).text.substring(0, lastColumn - 1);
       r.addAll(
           scanLineForLocalVariableLocations(pattern,
                                              name,
                                              lineContents,
                                              line,
                                              0));
     }
     return r;
   }
@@ skipping 714 matching lines @@
     var v = list[i];
     if ((v is ObservableMap) && _isServiceMap(v)) {
       list[i] = owner.getFromMap(v);
     } else if (v is ObservableList) {
       _upgradeObservableList(v, owner);
     } else if (v is ObservableMap) {
       _upgradeObservableMap(v, owner);
     }
   }
 }