Issue 36682. Check that selection offset/length is valid in Extract Method refactoring.

[email protected]

Bug: #36682
Change-Id: I9b15983ff6a872eec14c48bdf29680e6db97a75e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/108480
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>

Author: scheglov

pkg/analysis_server/lib/src/services/refactoring/extract_method.dart

@@ -464,6 +464,15 @@ class ExtractMethodRefactoringImpl extends RefactoringImpl
    * location of this [DartExpression] in AST allows extracting.
    */
   RefactoringStatus _checkSelection() {
+    if (selectionOffset <= 0) {
+      return new RefactoringStatus.fatal(
+          'The selection offset must be greater than zero.');
+    }
+    if (selectionOffset + selectionLength >= resolveResult.content.length) {
+      return new RefactoringStatus.fatal(
+          'The selection end offset must be less then the length of the file.');
+    }
+
     // Check for implicitly selected closure.
     {
       FunctionExpression function = _findFunctionExpression();

pkg/analysis_server/test/services/refactoring/extract_method_test.dart

@@ -296,7 +296,7 @@ main() {
 
   test_bad_namePartOfDeclaration_function() async {
     await indexTestUnit('''
-main() {
+void main() {
 }
 ''');
     _createRefactoringForString('main');
@@ -762,6 +762,28 @@ main() {
     expect(refactoring.createGetter, true);
   }
 
+  test_checkInitialCondition_false_outOfRange_length() async {
+    await indexTestUnit('''
+main() {
+  1 + 2;
+}
+''');
+    _createRefactoring(0, 1 << 20);
+    RefactoringStatus status = await refactoring.checkAllConditions();
+    assertRefactoringStatus(status, RefactoringProblemSeverity.FATAL);
+  }
+
+  test_checkInitialCondition_outOfRange_offset() async {
+    await indexTestUnit('''
+main() {
+  1 + 2;
+}
+''');
+    _createRefactoring(-10, 20);
+    RefactoringStatus status = await refactoring.checkAllConditions();
+    assertRefactoringStatus(status, RefactoringProblemSeverity.FATAL);
+  }
+
   test_checkName() async {
     await indexTestUnit('''
 main() {
@@ -1071,6 +1093,24 @@ class A {
     expect(refactoring.refactoringName, 'Extract Method');
   }
 
+  test_isAvailable_false_functionName() async {
+    await indexTestUnit('''
+void main() {}
+''');
+    _createRefactoringForString('main');
+    expect(refactoring.isAvailable(), isFalse);
+  }
+
+  test_isAvailable_true() async {
+    await indexTestUnit('''
+main() {
+  1 + 2;
+}
+''');
+    _createRefactoringForString('1 + 2');
+    expect(refactoring.isAvailable(), isTrue);
+  }
+
   test_names_singleExpression() async {
     await indexTestUnit('''
 class TreeItem {}