matchAnnotation and instantiateAnnotation break on extended classes

[thosakwe]

Hi, I'm experiencing an error that is blocking my progress using package:source_gen. I am more than happy to submit a PR to fix it, but I'd need clearance first.

Anyways, I'm building a PostgreSQL ORM generator, driven by a few annotations. I chose to model relations the following way:

class Relationship {
  final String localKey;
  final String foreignKey;
  final String foreignTable;
  final bool cascadeOnDelete;

  const Relationship._(
      {this.localKey,
      this.foreignKey,
      this.foreignTable,
      this.cascadeOnDelete});
}

class HasMany extends Relationship {
  const HasMany(
      {String localKey,
      String foreignKey,
      String foreignTable,
      bool cascadeOnDelete: false})
      : super._(
            localKey: localKey,
            foreignKey: foreignKey,
            foreignTable: foreignTable,
            cascadeOnDelete: cascadeOnDelete == true);
}

const HasMany hasMany = const HasMany();  
// HasOne and BelongsTo (omitted here) are virtually identical to HasMany

I've written a helper findAnnotation<T> function that calls matchAnnotation and instantiateAnnotation in one go.

import 'package:analyzer/dart/element/element.dart';
import 'package:source_gen/src/annotation.dart';

T findAnnotation<T>(FieldElement field, Type outType) {
  var first = field.metadata
      .firstWhere((ann) => matchAnnotation(outType, ann), orElse: () => null);
  return first == null ? null : instantiateAnnotation(first);
}

Firstly, matchAnnotation is not able to tell that @hasMany is an instance of Relationship.
I hacked around this by instead searching for a HasMany or HasOne, etc.

But instantiateAnnotation crashes with the following error when encountering a child class:

PS C:\Users\thosa\Source\Angel\postgres> dart tool/build.dart
[INFO] Build: Reading cached dependency graph...
[INFO] Build: Reading cached dependency graph completed, took 15ms
[INFO] Build: Finalizing build setup...
[INFO] Build: Updating dependency graph with changes since last build.
[INFO] Build: Initializing inputs
[INFO] Build: Deleting previous outputs
[INFO] Build: Deleting 3 declared outputs which already existed on disk.
[INFO] Build: Finalizing build setup completed, took 192ms
[INFO] Build: Running build...
[INFO] runBuilder: Hm: make
[INFO] runBuilder: Hm: description
[INFO] runBuilder: Hm: familyFriendly
[INFO] runBuilder: Hm: recalledAt
[SEVERE] runBuilder: Error running PostgresORMGenerator for class _Car extends Model.
type 'SuperConstructorInvocationImpl' is not a subtype of type 'ConstructorFieldInitializer' in type cast where
  SuperConstructorInvocationImpl is from package:analyzer/src/dart/ast/ast.dart
  ConstructorFieldInitializer is from package:analyzer/dart/ast/ast.dart

#0      Object._as (dart:core-patch/object_patch.dart:73)
#1      _createFromConstructor.<anonymous closure> (package:source_gen/src/annotation.dart:153:30)
#2      Object&ListMixin.singleWhere (dart:collection/list.dart:155)
#3      _createFromConstructor (package:source_gen/src/annotation.dart:152:51)
#4      instantiateAnnotation (package:source_gen/src/annotation.dart:44:12)
#5      findAnnotation (package:angel_orm/src/builder/find_annotation.dart:7:33)
#6      buildContext (package:angel_orm/src/builder/postgres/build_context.dart:27:11)
#7      PostgresORMGenerator.generateForAnnotatedElement (package:angel_orm/src/builder/postgres/postgres.dart:31:9)
#8      GeneratorForAnnotation.generate (package:source_gen/src/generator_for_annotation.dart:34:12)
#9      _processUnitMember (package:source_gen/src/builder.dart:119:35)
<asynchronous suspension>
#10     _generate (package:source_gen/src/builder.dart:110:12)
<asynchronous suspension>
#11     GeneratorBuilder._generateForLibrary (package:source_gen/src/builder.dart:55:15)
<asynchronous suspension>
#12     GeneratorBuilder.build (package:source_gen/src/builder.dart:40:11)
<asynchronous suspension>
#13     runBuilder.buildForInput (package:build/src/generate/run_builder.dart:35:21)
<asynchronous suspension>
#14     MappedListIterable.elementAt (dart:_internal/iterable.dart:413)
#15     ListIterator.moveNext (dart:_internal/iterable.dart:342)
#16     Future.wait (dart:async/future.dart:355)
#17     runBuilder.<anonymous closure> (package:build/src/generate/run_builder.dart:41:31)
#18     _rootRun (dart:async/zone.dart:1120)
#19     _CustomZone.run (dart:async/zone.dart:1001)
#20     runZoned (dart:async/zone.dart:1467)
#21     scopeLog (package:build/src/builder/logging.dart:12:38)
#22     runBuilder (package:build/src/generate/run_builder.dart:41:9)
<asynchronous suspension>
#23     BuildImpl._runBuilder (package:build_runner/src/generate/build_impl.dart:554:13)
<asynchronous suspension>
#24     BuildImpl._runPhases.<anonymous closure> (package:build_runner/src/generate/build_impl.dart:442:34)
<asynchronous suspension>
#25     MappedListIterable.elementAt (dart:_internal/iterable.dart:413)
#26     ListIterator.moveNext (dart:_internal/iterable.dart:342)
#27     Future.wait (dart:async/future.dart:355)
#28     BuildImpl._runPhases (package:build_runner/src/generate/build_impl.dart:440:20)
<asynchronous suspension>
#29     logWithTime (package:build_runner/src/logging/logging.dart:19:28)
<asynchronous suspension>
#30     BuildImpl.runBuild.<anonymous closure> (package:build_runner/src/generate/build_impl.dart:146:26)
<asynchronous suspension>
#31     Chain.capture.<anonymous closure> (package:stack_trace/src/chain.dart:93:24)
#32     _rootRun (dart:async/zone.dart:1120)
#33     _CustomZone.run (dart:async/zone.dart:1001)
#34     runZoned (dart:async/zone.dart:1467)
#35     Chain.capture (package:stack_trace/src/chain.dart:91:12)
#36     BuildImpl.runBuild (package:build_runner/src/generate/build_impl.dart:78:11)
<asynchronous suspension>
#37     build (package:build_runner/src/generate/build.dart:65:32)
<asynchronous suspension>
#38     main (file:///C:/Users/thosa/Source/Angel/postgres/tool/build.dart:4:11)
#39     _startIsolate.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:265)
#40     _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:151)

[INFO] Build: Running build completed, took 2420ms
[INFO] Build: Caching finalized dependency graph...
[INFO] Build: Caching finalized dependency graph completed, took 14ms
[INFO] Build: Succeeded after 2659ms with 3 outputs

Is there any way to support annotations that are extended from other classes, or is this currently impossible?

Thanks in advance for your response, and thanks for all the hard work.

[thosakwe]

Ok, so if anybody is reading this, I have a fork where I've now patched getAnnotation to ignore a SuperClassInvocation when it sees one: https://github.com/thosakwe/source_gen

I would also like to patch matchAnnotation to match extended classes, but I'd rather have that in a separate pull request.

My question is: How do I run the tests for this package? I added a test, and can't verify it works. I receive this error when running pub run test:

Bad state: A package configuration file was not found at the expectetd location. \C:\Users\thosa\Source\Dart\source_gen\.packages

test\analysis_utils.dart 58:5     _getPackageResolver
test\analysis_utils.dart 32:25    getAnalysisContextForProjectPath
test\annotation_test.dart 228:23  _getTestLibElement
test\annotation_test.dart 32:26   main.<fn>
===== asynchronous gap ===========================
dart:async                        _Completer.completeError
test\analysis_utils.dart 52:1     getAnalysisContextForProjectPath
===== asynchronous gap ===========================
dart:async                        new Future.microtask
test\analysis_utils.dart 24:56    getAnalysisContextForProjectPath
test\annotation_test.dart 228:23  _getTestLibElement
===== asynchronous gap ===========================
dart:async                        _asyncThenWrapperHelper
test\annotation_test.dart 220:51  _getTestLibElement
test\annotation_test.dart 32:26   main.<fn>
===== asynchronous gap ===========================
dart:async                        new Future.microtask
test\annotation_test.dart 30:18   main.<fn>

Process finished with exit code 1

The path \C:\Users\thosa\Source\Dart\source_gen\.packages definitely exists, and certainly is a file.
I'm guessing this may have to do with that leading slash (I'm on Windows).

[thosakwe]

Okay, so the Windows thing was definitely the reason the tests didn't load. Time to send in a PR.

[jakemac53]

I think you are just the first one to try and use annotations that extend another class :). Seems like a reasonable thing to expect to work though.

[matanlurey]

Closed as part of #159.