Get the language version of BazelWorkspace from the dart/build_defs/bzl/language.bzl

Presubmit looks green.
https://fusion2.corp.google.com/presubmit/tap/398141496/OCL:398141496:BASE:398160873:1632289516597:2c6df414/targets

Change-Id: Ibe12b4d0709cd38be0307a6c211962dca7a69de6
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/214075
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>

pkg/analyzer/lib/src/workspace/bazel.dart

@@ -206,6 +206,9 @@ class BazelWorkspace extends Workspace
   /// to avoid this in cases when `BUILD` files are always available.
   final bool _lookForBuildFileSubstitutes;
 
+  /// The language version for this workspace, `null` if cannot be read.
+  final Version? _languageVersion;
+
   /// The cache of packages. The key is the directory path, the value is
   /// the corresponding package.
   final Map<String, BazelWorkspacePackage> _directoryToPackage = {};
@@ -220,7 +223,8 @@ class BazelWorkspace extends Workspace
     this.binPaths,
     this.genfiles, {
     required bool lookForBuildFileSubstitutes,
-  }) : _lookForBuildFileSubstitutes = lookForBuildFileSubstitutes;
+  })  : _lookForBuildFileSubstitutes = lookForBuildFileSubstitutes,
+        _languageVersion = _readLanguageVersion(provider, root);
 
   /// Stream of files that we tried to find along with their potential or actual
   /// paths.
@@ -564,6 +568,33 @@ class BazelWorkspace extends Workspace
   static Folder? _firstExistingFolder(Folder root, List<String> names) => names
       .map((name) => root.getChildAssumingFolder(name))
       .firstWhereOrNull((folder) => folder.exists);
+
+  /// Return the default language version of the workspace.
+  ///
+  /// Return `null` if cannot be read, for example because the file does not
+  /// exist, or is not available in this build configuration (batch analysis).
+  static Version? _readLanguageVersion(
+    ResourceProvider resourceProvider,
+    String rootPath,
+  ) {
+    var file = resourceProvider.getFile(
+      resourceProvider.pathContext.joinAll(
+        [rootPath, 'dart', 'build_defs', 'bzl', 'language.bzl'],
+      ),
+    );
+
+    String content;
+    try {
+      content = file.readAsStringSync();
+    } on FileSystemException {
+      return null;
+    }
+
+    final pattern = RegExp(r'_version_null_safety\s*=\s*"(\d+\.\d+)"');
+    for (var match in pattern.allMatches(content)) {
+      return Version.parse('${match.group(1)}.0');
+    }
+  }
 }
 
 /// Information about a package defined in a BazelWorkspace.
@@ -597,7 +628,7 @@ class BazelWorkspacePackage extends WorkspacePackage {
   @override
   Version? get languageVersion {
     _readBuildFile();
-    return _languageVersion;
+    return _languageVersion ?? workspace._languageVersion;
   }
 
   @override

pkg/analyzer/test/src/dart/resolution/non_nullable_bazel_workspace_test.dart

@@ -2,6 +2,9 @@
 // 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/src/dart/analysis/experiments.dart';
+import 'package:pub_semver/pub_semver.dart';
+import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'context_collection_resolution.dart';
@@ -63,6 +66,52 @@ dart_package(
     assertType(findNode.namedType('int v'), 'int');
   }
 
+  test_buildFile_nonNullable_languageVersion_current() async {
+    newFile('$myPackageRootPath/BUILD', content: r'''
+dart_package(
+  null_safety = True,
+)
+''');
+
+    await resolveFileCode(
+      '$myPackageRootPath/lib/a.dart',
+      'int v = 0;',
+    );
+    _assertLanguageVersion(
+      package: ExperimentStatus.currentVersion,
+      override: null,
+    );
+  }
+
+  test_buildFile_nonNullable_languageVersion_fromWorkspace() async {
+    newFile('$workspaceRootPath/dart/build_defs/bzl/language.bzl', content: r'''
+_version = "2.9"
+_version_null_safety = "2.14"
+_version_for_analyzer = _version_null_safety
+
+language = struct(
+    version = _version,
+    version_null_safety = _version_null_safety,
+    version_for_analyzer = _version_for_analyzer,
+)
+''');
+
+    newFile('$myPackageRootPath/BUILD', content: r'''
+dart_package(
+  null_safety = True,
+)
+''');
+
+    await resolveFileCode(
+      '$myPackageRootPath/lib/a.dart',
+      'int v = 0;',
+    );
+    _assertLanguageVersion(
+      package: Version.parse('2.14.0'),
+      override: null,
+    );
+  }
+
   test_buildFile_nonNullable_oneLine_noComma() async {
     newFile('$myPackageRootPath/BUILD', content: r'''
 dart_package(null_safety = True)
@@ -99,4 +148,13 @@ int v = 0;
 
     assertType(findNode.namedType('int v'), 'int*');
   }
+
+  void _assertLanguageVersion({
+    required Version package,
+    required Version? override,
+  }) async {
+    var element = result.libraryElement;
+    expect(element.languageVersion.package, package);
+    expect(element.languageVersion.override, override);
+  }
 }