[nnbd_migration] handle multiple contexts

Bug: dart-lang/sdk#42141
Change-Id: I64179cd3fa0389397a8a9b3a763fbb1a3719294e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/149664
Commit-Queue: Devon Carew <[email protected]>
Reviewed-by: Paul Berry <[email protected]>

Author: devoncarew

pkg/nnbd_migration/lib/migration_cli.dart

@@ -6,6 +6,7 @@ import 'dart:async';
 import 'dart:convert' show jsonDecode;
 import 'dart:io' hide File;
 
+import 'package:analyzer/dart/analysis/analysis_context_collection.dart';
 import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/diagnostic/diagnostic.dart';
 import 'package:analyzer/error/error.dart';
@@ -155,8 +156,8 @@ class DependencyChecker {
       _logger.stderr('Visit https://dart.dev/tools/pub/cmd/pub-outdated for '
           'more information.');
       _logger.stderr('');
-      _logger.stderr('Force migration with '
-          '--${CommandLineOptions.skipPubOutdatedFlag} (not recommended)');
+      _logger.stderr('You can force migration with '
+          "'--${CommandLineOptions.skipPubOutdatedFlag}' (not recommended).");
       return false;
     }
     return true;
@@ -235,6 +236,8 @@ class MigrationCli {
 
   _FixCodeProcessor _fixCodeProcessor;
 
+  AnalysisContextCollection _contextCollection;
+
   MigrationCli(
       {@required this.binaryName,
       @visibleForTesting this.loggerFactory = _defaultLoggerFactory,
@@ -316,6 +319,12 @@ class MigrationCli {
               argResults[CommandLineOptions.skipPubOutdatedFlag] as bool,
           summary: argResults[CommandLineOptions.summaryOption] as String,
           webPreview: webPreview);
+
+      _contextCollection = AnalysisContextCollectionImpl(
+          includedPaths: [options.directory],
+          resourceProvider: resourceProvider,
+          sdkPath: pathContext.normalize(options.sdkPath));
+
       if (isVerbose) {
         logger = loggerFactory(true);
       }
@@ -352,16 +361,19 @@ class MigrationCli {
     logger.stdout('Migrating ${options.directory}');
     logger.stdout('');
 
+    if (hasMultipleAnalysisContext) {
+      logger.stdout(
+          'Note: more than one project found; migrating the top-level project.');
+      logger.stdout('');
+    }
+
+    DriverBasedAnalysisContext context = analysisContext;
+
     List<String> previewUrls;
     NonNullableFix nonNullableFix;
+
     await _withProgress(
         '${ansi.emphasized('Generating migration suggestions')}', () async {
-      var contextCollection = AnalysisContextCollectionImpl(
-          includedPaths: [options.directory],
-          resourceProvider: resourceProvider,
-          sdkPath: options.sdkPath);
-      DriverBasedAnalysisContext context =
-          contextCollection.contexts.single as DriverBasedAnalysisContext;
       _fixCodeProcessor = _FixCodeProcessor(context, this);
       _dartFixListener =
           DartFixListener(DriverProviderImpl(resourceProvider, context));
@@ -376,6 +388,8 @@ class MigrationCli {
       _fixCodeProcessor.nonNullableFixTask = nonNullableFix;
 
       try {
+        // TODO(devoncarew): The progress written by the fix processor conflicts
+        // with the progress written by the ansi logger above.
         await _fixCodeProcessor.runFirstPhase();
         _fixCodeProcessor._progressBar.clear();
         _checkForErrors();
@@ -437,6 +451,23 @@ Use this interactive web view to review, improve, or apply the results.
     exitCode = 0;
   }
 
+  @visibleForTesting
+  DriverBasedAnalysisContext get analysisContext {
+    // Handle the case of more than one analysis context being found (typically,
+    // the current directory and one or more sub-directories).
+    if (hasMultipleAnalysisContext) {
+      return _contextCollection.contextFor(options.directory)
+          as DriverBasedAnalysisContext;
+    } else {
+      return _contextCollection.contexts.single as DriverBasedAnalysisContext;
+    }
+  }
+
+  @visibleForTesting
+  bool get hasMultipleAnalysisContext {
+    return _contextCollection.contexts.length > 1;
+  }
+
   /// Perform the indicated source edits to the given source, returning the
   /// resulting transformed text.
   String _applyEdits(SourceFileEdit sourceFileEdit, String source) {

pkg/nnbd_migration/test/migration_cli_test.dart

@@ -362,6 +362,39 @@ int${migrated ? '?' : ''} f() => null;
     assertProjectContents(projectDir, simpleProject(migrated: true));
   }
 
+  test_lifecycle_contextdiscovery_handles_multiple() async {
+    var projectContents = simpleProject();
+    var subProject = simpleProject();
+    for (var filePath in subProject.keys) {
+      projectContents['example/$filePath'] = subProject[filePath];
+    }
+    projectContents['example/analysis_options.yaml'] = '''
+analyzer:
+  strong-mode:
+    implicit-casts: false
+linter:
+  rules:
+    - empty_constructor_bodies
+''';
+
+    var projectDir = await createProjectDir(projectContents);
+    var cli = _createCli();
+    await cli.run(_parseArgs(['--no-web-preview', projectDir]));
+    expect(cli.hasMultipleAnalysisContext, true);
+    expect(cli.analysisContext, isNotNull);
+    var output = logger.stdoutBuffer.toString();
+    expect(output, contains('more than one project found'));
+  }
+
+  test_lifecycle_contextdiscovery_handles_single() async {
+    var projectContents = simpleProject();
+    var projectDir = await createProjectDir(projectContents);
+    var cli = _createCli();
+    await cli.run(_parseArgs(['--no-web-preview', projectDir]));
+    expect(cli.hasMultipleAnalysisContext, false);
+    expect(cli.analysisContext, isNotNull);
+  }
+
   test_lifecycle_ignore_errors_disable() async {
     var projectContents = simpleProject(sourceText: '''
 int f() => null
@@ -918,7 +951,7 @@ int f() => null;
   }
 
   test_migrate_path_normalized() {
-    expect(assertParseArgsSuccess(['..']).directory, isNot(contains('..')));
+    expect(assertParseArgsSuccess(['foo/..']).directory, isNot(contains('..')));
   }
 
   test_migrate_path_one() {