Fix resolving nested serialized types

moor_generator/lib/src/backends/build/build_backend.dart

@@ -8,7 +8,6 @@ import 'package:build/build.dart' as build show log;
 import 'package:logging/logging.dart';
 import 'package:moor_generator/src/analyzer/options.dart';
 import 'package:moor_generator/src/backends/backend.dart';
-import 'package:moor_generator/src/backends/build/serialized_types.dart';
 
 class BuildBackend extends Backend {
   final MoorOptions options;
@@ -29,10 +28,8 @@ class BuildBackend extends Backend {
 class BuildBackendTask extends BackendTask {
   final BuildStep step;
   final BuildBackend backend;
-  final TypeDeserializer typeDeserializer;
 
-  BuildBackendTask(this.step, this.backend)
-      : typeDeserializer = TypeDeserializer(step);
+  BuildBackendTask(this.step, this.backend);
 
   @override
   Uri get entrypoint => step.inputId.uri;
@@ -76,6 +73,7 @@ class BuildBackendTask extends BackendTask {
     // prepare the result. See PreprocessBuilder for details
     final preparedHelperFile =
         _resolve(context).changeExtension('.dart_in_moor');
+    final temporaryFile = _resolve(context).changeExtension('.temp.dart');
 
     if (!await step.canRead(preparedHelperFile)) {
       throw CannotLoadTypeException('Generated helper file not found. '
@@ -83,10 +81,17 @@ class BuildBackendTask extends BackendTask {
     }
 
     final content = await step.readAsString(preparedHelperFile);
-    final json = jsonDecode(content) as Map<String, dynamic>;
-    final serializedType = json[dartExpression] as Map<String, dynamic>;
+    final json =
+        (jsonDecode(content) as Map<String, dynamic>).cast<String, String>();
+    final fieldName = json[dartExpression];
+    if (fieldName == null) {
+      throw CannotLoadTypeException('Generated helper file does not contain '
+          '$dartExpression!');
+    }
 
-    return typeDeserializer
-        .deserialize(SerializedType.fromJson(serializedType));
+    final library = await step.resolver.libraryFor(temporaryFile);
+    final field = library.units.first.topLevelVariables
+        .firstWhere((element) => element.name == fieldName);
+    return field.type;
   }
 }

moor_generator/lib/src/backends/build/preprocess_builder.dart

@@ -2,10 +2,7 @@
 import 'dart:async';
 import 'dart:convert';
 
-import 'package:analyzer/dart/ast/ast.dart';
-import 'package:analyzer/dart/element/element.dart';
 import 'package:build/build.dart';
-import 'package:moor_generator/src/backends/build/serialized_types.dart';
 import 'package:moor_generator/src/utils/string_escaper.dart';
 import 'package:sqlparser/sqlparser.dart';
 
@@ -85,8 +82,11 @@ class PreprocessBuilder extends Builder {
     final importedDartFiles =
         seenFiles.where((asset) => asset.extension == '.dart');
 
+    final codeToField = <String, String>{};
+
     // to analyze the expressions, generate a fake Dart file that declares each
-    // expression in a `var`, we can then read the static type.
+    // expression in a `var`, we can then read the static type when resolving
+    // file later.
 
     final dartBuffer = StringBuffer();
     for (final import in importedDartFiles) {
@@ -95,38 +95,20 @@ class PreprocessBuilder extends Builder {
     }
 
     for (var i = 0; i < dartLexemes.length; i++) {
-      dartBuffer.write('var ${_nameForDartExpr(i)} = ${dartLexemes[i]};\n');
+      final name = _nameForDartExpr(i);
+      dartBuffer.write('var $name = ${dartLexemes[i]};\n');
+      codeToField[dartLexemes[i]] = name;
     }
 
     final tempDartAsset = input.changeExtension('.temp.dart');
+
+    // Await the file needed to resolve types.
     await buildStep.writeAsString(tempDartAsset, dartBuffer.toString());
 
-    // we can now resolve the library we just wrote
-
-    final createdLibrary = await buildStep.resolver.libraryFor(tempDartAsset);
-    final serializer = TypeSerializer(buildStep.resolver);
-    final codeToType = <String, SerializedType>{};
-
-    for (var i = 0; i < dartLexemes.length; i++) {
-      final member =
-          _findVariableDefinition(_nameForDartExpr(i), createdLibrary);
-      final node = await buildStep.resolver.astNodeFor(member, resolve: true)
-          as VariableDeclaration;
-
-      final type = node.initializer.staticType;
-      codeToType[dartLexemes[i]] = await serializer.serialize(type);
-    }
-
+    // And the file mapping Dart expressions onto the variable names here
     final outputAsset = input.changeExtension('.dart_in_moor');
-    await buildStep.writeAsString(outputAsset, jsonEncode(codeToType));
+    await buildStep.writeAsString(outputAsset, json.encode(codeToField));
   }
 
   String _nameForDartExpr(int i) => 'expr_$i';
-
-  TopLevelVariableElement _findVariableDefinition(
-      String name, LibraryElement element) {
-    return element.units
-        .expand((u) => u.topLevelVariables)
-        .firstWhere((e) => e.name == name);
-  }
 }

moor_generator/lib/src/backends/build/serialized_types.dart

@@ -1,159 +0,0 @@
-//@dart=2.9
-import 'dart:async';
-
-import 'package:analyzer/dart/analysis/results.dart';
-import 'package:analyzer/dart/analysis/session.dart';
-import 'package:analyzer/dart/element/element.dart';
-import 'package:analyzer/dart/element/nullability_suffix.dart';
-import 'package:analyzer/dart/element/type.dart';
-import 'package:build/build.dart';
-import 'package:moor_generator/src/backends/backend.dart';
-import 'package:source_gen/source_gen.dart';
-
-/// A serialized version of a [DartType].
-abstract class SerializedType {
-  factory SerializedType.fromJson(Map<String, dynamic> json) {
-    switch (json['type'] as String) {
-      case 'interface':
-        return _SerializedInterfaceType.fromJson(json);
-    }
-    throw ArgumentError('Unknown type kind: ${json['type']}');
-  }
-
-  SerializedType();
-
-  Map<String, dynamic> toJson();
-}
-
-// todo handle non-interface types, recursive types
-
-class _SerializedInterfaceType extends SerializedType {
-  final Uri libraryUri;
-  final String className;
-  final List<SerializedType> typeArgs;
-
-  _SerializedInterfaceType(this.libraryUri, this.className, this.typeArgs);
-
-  factory _SerializedInterfaceType.fromJson(Map<String, dynamic> json) {
-    final serializedTypes = json['type_args'] as List;
-
-    return _SerializedInterfaceType(
-      Uri.parse(json['library'] as String),
-      json['class_name'] as String,
-      serializedTypes
-          .map((raw) => SerializedType.fromJson(raw as Map<String, dynamic>))
-          .toList(),
-    );
-  }
-
-  @override
-  Map<String, dynamic> toJson() {
-    return {
-      'type': 'interface',
-      'library': libraryUri.toString(),
-      'class_name': className,
-      'type_args': [for (var type in typeArgs) type.toJson()],
-    };
-  }
-}
-
-class TypeSerializer {
-  final Resolver resolver;
-
-  TypeSerializer(this.resolver);
-
-  Future<SerializedType> serialize(DartType type) async {
-    if (type is InterfaceType) {
-      final dartClass = type.element;
-
-      Uri uri;
-      if (dartClass.librarySource.uri.scheme == 'dart') {
-        uri = dartClass.librarySource.uri;
-      } else {
-        uri = (await resolver.assetIdForElement(dartClass)).uri;
-      }
-
-      final serializedArgs =
-          await Future.wait(type.typeArguments.map(serialize));
-
-      return _SerializedInterfaceType(
-        uri,
-        dartClass.name,
-        serializedArgs,
-      );
-    } else {
-      throw UnsupportedError(
-          "Couldn't serialize $type, we only support interface types");
-    }
-  }
-}
-
-class TypeDeserializer {
-  /// The [BuildStep] used to resolve
-  final BuildStep buildStep;
-
-  /// The analysis session used to read libraries from the Dart SDK which can't
-  /// be obtained via build apis.
-  AnalysisSession _lastSession;
-
-  TypeDeserializer(this.buildStep);
-
-  Future<DartType> deserialize(SerializedType type) async {
-    if (type is _SerializedInterfaceType) {
-      final library = await _libraryFromUri(type.libraryUri);
-      final args = await Future.wait(type.typeArgs.map(deserialize));
-
-      return LibraryReader(library).findType(type.className).instantiate(
-          typeArguments: args, nullabilitySuffix: NullabilitySuffix.star);
-    }
-
-    throw AssertionError('Unhandled type: $type');
-  }
-
-  Future<LibraryElement> _libraryFromUri(Uri uri) async {
-    if (uri.scheme == 'dart') {
-      var session = await _obtainSession();
-
-      // The session could be invalidated by other builders outside of our
-      // control. There's no better way than to continue fetching a new session
-      // in that case.
-      var attempts = 0;
-      const maxAttempts = 5;
-
-      // ignore: literal_only_boolean_expressions
-      while (true) {
-        try {
-          final info = await session.getLibraryByUri2(uri.toString());
-          if (info is LibraryElementResult) {
-            return info.element;
-          } else {
-            throw NotALibraryException(uri);
-          }
-        } on InconsistentAnalysisException {
-          _lastSession = null; // Invalidate session, then try again
-          session = await _obtainSession();
-          attempts++;
-
-          if (attempts == maxAttempts) rethrow;
-        }
-      }
-    } else {
-      final library = await buildStep.resolver.libraryFor(AssetId.resolve(uri));
-      _lastSession ??= library?.session;
-      return library;
-    }
-  }
-
-  FutureOr<AnalysisSession> _obtainSession() {
-    if (_lastSession != null) {
-      return _lastSession;
-    } else {
-      // resolve bogus library that's not going to change often. We can use the
-      // session from that library. Technically, this is non-hermetic, but the
-      // build runner will throw everything away after an SDK update so it
-      // should be safe
-      return _libraryFromUri(Uri.parse('package:moor/sqlite_keywords.dart'))
-          .then((_) => _lastSession);
-    }
-  }
-}