Migration: create a simple client of the migration API for early test…

…ing.

Change-Id: I889f7b80fdbb8dbddd8174812ddaca013cf272e3
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/112361
Commit-Queue: Paul Berry <paulberry@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Reviewed-by: Konstantin Shcheglov <scheglov@google.com>

pkg/nnbd_migration/tool/trial_migration.dart

@@ -0,0 +1,139 @@
+// Copyright (c) 2019, 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.
+
+// This is a hacked-together client of the NNBD migration API, intended for
+// early testing of the migration process.  It runs a small hardcoded set of
+// packages through the migration engine and outputs statistics about the
+// result of migration, as well as categories (and counts) of exceptions that
+// occurred.
+
+import 'dart:io';
+
+import 'package:analyzer/dart/analysis/analysis_context_collection.dart';
+import 'package:analyzer_plugin/protocol/protocol_common.dart';
+import 'package:nnbd_migration/nnbd_migration.dart';
+
+main() async {
+  var rootUri = Platform.script.resolve('../../..');
+  var listener = _Listener();
+  for (var testPath in [
+    'third_party/pkg/charcode',
+    'third_party/pkg/collection',
+    'third_party/pkg/logging',
+    'pkg/meta',
+    'third_party/pkg/path',
+    'third_party/pkg/term_glyph',
+//    'third_party/pkg/typed_data', - TODO(paulberry): fatal exception
+    'third_party/pkg/async',
+    'third_party/pkg/source_span',
+    'third_party/pkg/stack_trace',
+    'third_party/pkg/matcher',
+    'third_party/pkg/stream_channel',
+    'third_party/pkg/boolean_selector',
+    'third_party/pkg/test/pkgs/test_api',
+  ]) {
+    print('Migrating $testPath');
+    var testUri = rootUri.resolve(testPath);
+    var contextCollection =
+        AnalysisContextCollection(includedPaths: [testUri.toFilePath()]);
+    var context = contextCollection.contexts.single;
+    var files = context.contextRoot
+        .analyzedFiles()
+        .where((s) => s.endsWith('.dart'))
+        .toList();
+    print('  ${files.length} files found');
+    var migration = NullabilityMigration(listener, permissive: true);
+    for (var file in files) {
+      var resolvedUnit = await context.currentSession.getResolvedUnit(file);
+      migration.prepareInput(resolvedUnit);
+    }
+    for (var file in files) {
+      var resolvedUnit = await context.currentSession.getResolvedUnit(file);
+      migration.processInput(resolvedUnit);
+    }
+    migration.finish();
+  }
+  print('${listener.numTypesMadeNullable} types made nullable');
+  print('${listener.numNullChecksAdded} null checks added');
+  print('${listener.numMetaImportsAdded} meta imports added');
+  print('${listener.numRequiredAnnotationsAdded} required annotations added');
+  print('${listener.numDeadCodeSegmentsFound} dead code segments found');
+  print('${listener.numExceptions} exceptions in '
+      '${listener.groupedExceptions.length} categories');
+  print('Exception categories:');
+  var sortedExceptions = listener.groupedExceptions.entries.toList();
+  sortedExceptions.sort((e1, e2) => e2.value.length.compareTo(e1.value.length));
+  for (var entry in sortedExceptions) {
+    print('  ${entry.key} (x${entry.value.length})');
+  }
+}
+
+class _Listener implements NullabilityMigrationListener {
+  final groupedExceptions = <String, List<String>>{};
+
+  int numExceptions = 0;
+
+  int numTypesMadeNullable = 0;
+
+  int numNullChecksAdded = 0;
+
+  int numMetaImportsAdded = 0;
+
+  int numRequiredAnnotationsAdded = 0;
+
+  int numDeadCodeSegmentsFound = 0;
+
+  @override
+  void addDetail(String detail) {
+    var breakLocation = detail.indexOf('\n\n');
+    if (breakLocation == -1)
+      throw StateError('Could not decode exception $detail');
+    var stackTrace = detail.substring(breakLocation + 2).split('\n');
+    var category = _classifyStackTrace(stackTrace);
+    (groupedExceptions[category] ??= []).add(detail);
+    ++numExceptions;
+  }
+
+  @override
+  void addEdit(SingleNullabilityFix fix, SourceEdit edit) {
+    if (edit.replacement == '?' && edit.length == 0) {
+      ++numTypesMadeNullable;
+    } else if (edit.replacement == '!' && edit.length == 0) {
+      ++numNullChecksAdded;
+    } else if (edit.replacement == "import 'package:meta/meta.dart';\n" &&
+        edit.length == 0) {
+      ++numMetaImportsAdded;
+    } else if (edit.replacement == '@required ' && edit.length == 0) {
+      ++numRequiredAnnotationsAdded;
+    } else if ((edit.replacement == '/* ' ||
+            edit.replacement == ' /*' ||
+            edit.replacement == '; /*') &&
+        edit.length == 0) {
+      ++numDeadCodeSegmentsFound;
+    } else if ((edit.replacement == '*/ ' || edit.replacement == ' */') &&
+        edit.length == 0) {
+      // Already counted
+    } else {
+      print('addEdit($fix, $edit)');
+    }
+  }
+
+  @override
+  void addFix(SingleNullabilityFix fix) {}
+
+  String _classifyStackTrace(List<String> stackTrace) {
+    for (var entry in stackTrace) {
+      if (entry.contains('EdgeBuilder._unimplemented')) continue;
+      if (entry.contains('_AssertionError._doThrowNew')) continue;
+      if (entry.contains('_AssertionError._throwNew')) continue;
+      if (entry.contains('NodeBuilder._unimplemented')) continue;
+      if (entry.contains('Object.noSuchMethod')) continue;
+      if (entry.contains('List.[] (dart:core-patch/growable_array.dart')) {
+        continue;
+      }
+      return entry;
+    }
+    return '???';
+  }
+}