analyzer: Extract out two common utilities for URIs

* Uri.isSamePackageAs(Uri) and Uri.isImplementation are each used a
  few times. Not as much as I would expect, but this still simplifies
  some code.

Change-Id: Ie9020916c793852a0df9d04154420948d942d951
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/413801
Commit-Queue: Samuel Rawlins <[email protected]>
Reviewed-by: Paul Berry <[email protected]>

Author: srawlins

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

@@ -21,8 +21,8 @@ import 'package:analyzer/source/source_range.dart';
 import 'package:analyzer/src/dart/ast/extensions.dart';
 import 'package:analyzer/src/dart/element/type.dart';
 import 'package:analyzer/src/dart/resolver/applicable_extensions.dart';
+import 'package:analyzer/utilities/extensions/uri.dart';
 import 'package:analyzer_plugin/src/utilities/change_builder/change_builder_dart.dart';
-import 'package:analyzer_plugin/src/utilities/library.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:analyzer_plugin/utilities/range_factory.dart';
@@ -369,8 +369,7 @@ class ImportLibrary extends MultiCorrectionProducer {
       }
       // If both files are in the same package's 'lib' folder, also include a
       // relative import.
-      var includeRelativeUri = canBeRelativeImport(
-        librarySource.uri,
+      var includeRelativeUri = librarySource.uri.isSamePackageAs(
         libraryElement2.uri,
       );
       // Add the fix(es).
@@ -388,6 +387,10 @@ class ImportLibrary extends MultiCorrectionProducer {
     return producers;
   }
 
+  /// Whether [path] appears to be a package-implementation source file.
+  ///
+  /// Note that this is approximate; without knowing the containing package's
+  /// location, this can give false positives.
   bool _isLibSrcPath(String path) {
     var parts = resourceProvider.pathContext.split(path);
     for (var i = 0; i < parts.length - 2; i++) {

pkg/analyzer/api.txt

@@ -5352,6 +5352,10 @@ package:analyzer/src/task/api/model.dart:
     source (getter: Source?)
 package:analyzer/src/workspace/workspace.dart:
   Workspace (non-public)
+package:analyzer/utilities/extensions/uri.dart:
+  UriExtension (extension on Uri):
+    isImplementation (getter: bool)
+    isSamePackageAs (method: bool Function(Uri))
 dart:async:
   Future (referenced)
   Stream (referenced)

pkg/analyzer/lib/utilities/extensions/uri.dart

@@ -0,0 +1,22 @@
+// Copyright (c) 2025, 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.
+
+extension UriExtension on Uri {
+  /// Whether this URI represents a path in a package's private "implementation"
+  /// directory.
+  bool get isImplementation =>
+      (isScheme('package') || !hasAbsolutePath) &&
+      pathSegments.length > 2 &&
+      pathSegments[1] == 'src';
+
+  /// Whether this URI and [other] are each 'package:' URIs referencing the same
+  /// package name.
+  bool isSamePackageAs(Uri other) {
+    return isScheme('package') &&
+        other.isScheme('package') &&
+        pathSegments.isNotEmpty &&
+        other.pathSegments.isNotEmpty &&
+        pathSegments.first == other.pathSegments.first;
+  }
+}

pkg/analyzer/test/test_all.dart

@@ -11,6 +11,7 @@ import 'generated/test_all.dart' as generated;
 import 'instrumentation/test_all.dart' as instrumentation;
 import 'source/test_all.dart' as source;
 import 'src/test_all.dart' as src;
+import 'utilities/test_all.dart' as utilities;
 import 'verify_diagnostics_test.dart' as verify_diagnostics;
 import 'verify_docs_test.dart' as verify_docs;
 import 'verify_tests_test.dart' as verify_tests;
@@ -24,6 +25,7 @@ main() {
     instrumentation.main();
     source.main();
     src.main();
+    utilities.main();
     verify_diagnostics.main();
     verify_docs.main();
     verify_tests.main();

pkg/analyzer/test/utilities/extensions/test_all.dart

@@ -0,0 +1,13 @@
+// Copyright (c) 2025, 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 'package:test_reflective_loader/test_reflective_loader.dart';
+
+import 'uri_test.dart' as uri;
+
+main() {
+  defineReflectiveSuite(() {
+    uri.main();
+  }, name: 'extensions');
+}

pkg/analyzer/test/utilities/extensions/uri_test.dart

@@ -0,0 +1,52 @@
+// Copyright (c) 2025, 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 'package:analyzer/utilities/extensions/uri.dart';
+import 'package:test/test.dart';
+import 'package:test_reflective_loader/test_reflective_loader.dart';
+
+main() {
+  defineReflectiveSuite(() {
+    defineReflectiveTests(UriExtensionTest);
+  });
+}
+
+@reflectiveTest
+class UriExtensionTest {
+  void test_isImplementation_packageScheme_insideSrc() {
+    expect(Uri.parse('package:foo/src/foo.dart').isImplementation, isTrue);
+  }
+
+  void test_isImplementation_packageScheme_outsideSrc() {
+    expect(Uri.parse('package:foo/foo.dart').isImplementation, isFalse);
+  }
+
+  void test_isImplementation_relative() {
+    expect(Uri.parse('foo.dart').isImplementation, isFalse);
+  }
+
+  void test_samePackage_nonPackageScheme() {
+    expect(
+      Uri.parse('file://foo/foo.dart')
+          .isSamePackageAs(Uri.parse('package:foo/bar.dart')),
+      isFalse,
+    );
+  }
+
+  void test_samePackage_packageScheme_notSame() {
+    expect(
+      Uri.parse('package:foo/foo.dart')
+          .isSamePackageAs(Uri.parse('package:bar/bar.dart')),
+      isFalse,
+    );
+  }
+
+  void test_samePackage_packageScheme_same() {
+    expect(
+      Uri.parse('package:foo/foo.dart')
+          .isSamePackageAs(Uri.parse('package:foo/bar.dart')),
+      isTrue,
+    );
+  }
+}

pkg/analyzer/test/utilities/test_all.dart

@@ -0,0 +1,13 @@
+// Copyright (c) 2025, 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 'package:test_reflective_loader/test_reflective_loader.dart';
+
+import 'extensions/test_all.dart' as extensions;
+
+main() {
+  defineReflectiveSuite(() {
+    extensions.main();
+  }, name: 'utilities');
+}

pkg/analyzer_plugin/lib/src/utilities/library.dart

@@ -8,6 +8,9 @@
 /// In other words, returns whether each is a 'package:' URI referencing the
 /// same package name.
 bool canBeRelativeImport(Uri library1, Uri library2) {
+  // TODO(srawlins): Replace this with `isSamePackageAs` from
+  // 'package:analyzer/src/utilities/extensions/uri.dart', once that is
+  // available on pub.
   return library1.isScheme('package') &&
       library2.isScheme('package') &&
       library1.pathSegments.isNotEmpty &&

pkg/linter/lib/src/rules/implementation_imports.dart

@@ -5,35 +5,12 @@
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element2.dart';
+import 'package:analyzer/utilities/extensions/uri.dart';
 
 import '../analyzer.dart';
 
 const _desc = r"Don't import implementation files from another package.";
 
-bool isImplementation(Uri? uri) {
-  var segments = uri?.pathSegments ?? const <String>[];
-  if (segments.length > 2) {
-    if (segments[1] == 'src') {
-      return true;
-    }
-  }
-  return false;
-}
-
-bool isPackage(Uri? uri) => uri?.scheme == 'package';
-
-bool samePackage(Uri? uri1, Uri? uri2) {
-  if (uri1 == null || uri2 == null) {
-    return false;
-  }
-  var segments1 = uri1.pathSegments;
-  var segments2 = uri2.pathSegments;
-  if (segments1.isEmpty || segments2.isEmpty) {
-    return false;
-  }
-  return segments1.first == segments2.first;
-}
-
 class ImplementationImports extends LintRule {
   ImplementationImports()
     : super(name: LintNames.implementation_imports, description: _desc);
@@ -49,8 +26,8 @@ class ImplementationImports extends LintRule {
     var libraryUri = context.libraryElement2?.uri;
     if (libraryUri == null) return;
 
-    // If the source URI is not a `package` URI bail out.
-    if (!isPackage(libraryUri)) return;
+    // If the source URI is not a `package` URI, bail out.
+    if (libraryUri.scheme != 'package') return;
 
     var visitor = _Visitor(this, libraryUri);
     registry.addImportDirective(this, visitor);
@@ -65,16 +42,15 @@ class _Visitor extends SimpleAstVisitor<void> {
 
   @override
   void visitImportDirective(ImportDirective node) {
-    Uri? importUri;
     if (node.libraryImport?.uri case DirectiveUriWithSource importedLibrary) {
-      importUri = importedLibrary.source.uri;
-    }
+      var importUri = importedLibrary.source.uri;
 
-    // Test for 'package:*/src/'.
-    if (!isImplementation(importUri)) return;
+      // Test for 'package:*/src/'.
+      if (!importUri.isImplementation) return;
 
-    if (!samePackage(importUri, sourceUri)) {
-      rule.reportLint(node.uri);
+      if (!importUri.isSamePackageAs(sourceUri)) {
+        rule.reportLint(node.uri);
+      }
     }
   }
 }

pkg/linter/lib/src/rules/prefer_relative_imports.dart

@@ -5,10 +5,10 @@
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element2.dart';
+import 'package:analyzer/utilities/extensions/uri.dart';
 import 'package:path/path.dart' as path;
 
 import '../analyzer.dart';
-import 'implementation_imports.dart' show samePackage;
 
 const _desc = r'Prefer relative imports for files in `lib/`.';
 
@@ -51,9 +51,10 @@ class _Visitor extends SimpleAstVisitor<void> {
       var importUri = importedLibrary.relativeUri;
       if (!importUri.isScheme('package')) return false;
 
-      if (!samePackage(importUri, sourceUri)) return false;
+      if (!importUri.isSamePackageAs(sourceUri)) return false;
 
-      // TODO(pq): context.package.contains(source) should work (but does not)
+      // TODO(pq): `context.package.contains(source)` should work (but does
+      // not).
       var packageRoot = context.package?.root;
       return packageRoot != null &&
           path.isWithin(packageRoot, importedLibrary.source.fullName);