[analyzer] Check conditional directive URIs are within the requested range

Change-Id: Icec5f864484a67dc3a64ace06704d8266d88c12b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/202772
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Brian Wilkerson <brianwilkerson@google.com>

pkg/analysis_server/test/analysis/get_navigation_test.dart

@@ -139,6 +139,37 @@ main() {
     expect(testTargets[0].kind, ElementKind.LIBRARY);
   }
 
+  Future<void> test_importUri_configurations() async {
+    final ioFile = newFile(join(testFolder, 'io.dart'));
+    final htmlFile = newFile(join(testFolder, 'html.dart'));
+    addTestFile('''
+import 'foo.dart'
+  if (dart.library.io) 'io.dart'
+  if (dart.library.html) 'html.dart';
+
+main() {
+}''');
+    await waitForTasksFinished();
+
+    // Request navigations for 'io.dart'
+    await _getNavigation(testFile, 41, 9);
+    expect(regions, hasLength(1));
+    assertHasRegionString("'io.dart'");
+    expect(testTargets, hasLength(1));
+    var target = testTargets.first;
+    expect(target.kind, ElementKind.LIBRARY);
+    expect(targetFiles[target.fileIndex], equals(ioFile.path));
+
+    // Request navigations for 'html.dart'
+    await _getNavigation(testFile, 76, 11);
+    expect(regions, hasLength(1));
+    assertHasRegionString("'html.dart'");
+    expect(testTargets, hasLength(1));
+    target = testTargets.first;
+    expect(target.kind, ElementKind.LIBRARY);
+    expect(targetFiles[target.fileIndex], equals(htmlFile.path));
+  }
+
   Future<void> test_invalidFilePathFormat_notAbsolute() async {
     var request = _createGetNavigationRequest('test.dart', 0, 0);
     var response = await waitResponse(request);

pkg/analyzer_plugin/lib/utilities/navigation/navigation_dart.dart

@@ -68,9 +68,7 @@ class _DartNavigationCollector {
       return;
     }
     // Discard elements that don't span the offset/range given (if provided).
-    if (requestedOffset != null &&
-        (offset > requestedOffset! + (requestedLength ?? 0) ||
-            offset + length < requestedOffset!)) {
+    if (!_isWithinRequestedRange(offset, length)) {
       return;
     }
     var converter = AnalyzerConverter();
@@ -154,6 +152,26 @@ class _DartNavigationCollector {
         offset: codeOffset, length: codeLength);
   }
 
+  /// Checks if offset/length intersect with the range the user requested
+  /// navigation regions for.
+  ///
+  /// If the request did not specify a range, always returns true.
+  bool _isWithinRequestedRange(int offset, int length) {
+    final requestedOffset = this.requestedOffset;
+    if (requestedOffset == null) {
+      return true;
+    }
+    if (offset > requestedOffset + (requestedLength ?? 0)) {
+      // Starts after the requested range.
+      return false;
+    }
+    if (offset + length < requestedOffset) {
+      // Ends before the requested range.
+      return false;
+    }
+    return true;
+  }
+
   static ElementDeclarationResult? _parsedDeclaration(Element element) {
     var session = element.session;
     if (session == null) {
@@ -243,11 +261,13 @@ class _DartNavigationComputerVisitor extends RecursiveAstVisitor<void> {
         // TODO(brianwilkerson) If the analyzer ever resolves the URI to a
         //  library, use that library element to create the region.
         var uriNode = node.uri;
-        computer.collector.addRegion(
-            uriNode.offset,
-            uriNode.length,
-            protocol.ElementKind.LIBRARY,
-            protocol.Location(source.fullName, 0, 0, 0, 0, 0, 0));
+        if (computer._isWithinRequestedRange(uriNode.offset, uriNode.length)) {
+          computer.collector.addRegion(
+              uriNode.offset,
+              uriNode.length,
+              protocol.ElementKind.LIBRARY,
+              protocol.Location(source.fullName, 0, 0, 0, 0, 0, 0));
+        }
       }
     }
     super.visitConfiguration(node);