Allow union types to have additional fields, support required fields.

Uses this feature to add an `id` field to request types, and
`requestId` to response types. These will be used to support multiple
ongoing requests and remove hacks with global variables for cfe/analyzer
internals.

pkgs/_analyzer_macros/lib/query_service.dart

@@ -20,7 +20,7 @@ analyzer.LinkedElementFactory get _elementFactory =>
 class AnalyzerQueryService implements QueryService {
   @override
   Future<QueryResponse> handle(QueryRequest request) async {
-    return QueryResponse(model: _evaluateClassQuery(request.query.target));
+    return QueryResponse(model: _evaluateClassQuery(request.query!.target!));
   }
 
   Model _evaluateClassQuery(QualifiedName target) {

pkgs/_cfe_macros/lib/query_service.dart

@@ -15,7 +15,7 @@ class CfeQueryService implements QueryService {
   @override
   Future<QueryResponse> handle(QueryRequest request) async {
     return QueryResponse(
-        model: await _evaluateClassQuery(request.query.target));
+        model: await _evaluateClassQuery(request.query!.target!));
   }
 
   Future<Model> _evaluateClassQuery(QualifiedName target) async {

pkgs/_macro_client/lib/macro_client.dart

@@ -30,7 +30,8 @@ class MacroClient {
     // Tell the host which macros are in this bundle.
     for (final macro in macros) {
       _sendRequest(MacroRequest.macroStartedRequest(
-          MacroStartedRequest(macroDescription: macro.description)));
+          MacroStartedRequest(macroDescription: macro.description),
+          id: nextRequestId));
     }
 
     const Utf8Decoder()
@@ -64,7 +65,8 @@ class MacroClient {
     switch (hostRequest.type) {
       case HostRequestType.augmentRequest:
         _sendResponse(Response.augmentResponse(
-            await macros.single.augment(_host, hostRequest.asAugmentRequest)));
+            await macros.single.augment(_host, hostRequest.asAugmentRequest),
+            requestId: hostRequest.id));
       default:
       // Ignore unknown request.
       // TODO(davidmorgan): make handling of unknown request types a designed
@@ -96,7 +98,8 @@ class RemoteMacroHost implements Host {
 
   @override
   Future<Model> query(Query query) async {
-    _client._sendRequest(MacroRequest.queryRequest(QueryRequest(query: query)));
+    _client._sendRequest(MacroRequest.queryRequest(QueryRequest(query: query),
+        id: nextRequestId));
     // TODO(davidmorgan): this is needed because the constructor doesn't wait
     // for responses to `MacroStartedRequest`, so we need to discard the
     // responses. Properly track requests and responses.
@@ -105,7 +108,7 @@ class RemoteMacroHost implements Host {
       if (nextResponse.type == ResponseType.macroStartedResponse) {
         continue;
       }
-      return nextResponse.asQueryResponse.model;
+      return nextResponse.asQueryResponse.model!;
     }
   }
 

pkgs/_macro_client/test/macro_client_test.dart

@@ -45,13 +45,15 @@ void main() {
           '{"type":"MacroStartedRequest","value":'
           '{"macroDescription":{"runsInPhases":[2]}}}');
 
-      socket.writeln(
-          json.encode(HostRequest.augmentRequest(AugmentRequest(phase: 2))));
+      var requestId = nextRequestId;
+      socket.writeln(json.encode(
+          HostRequest.augmentRequest(AugmentRequest(phase: 2), id: requestId)));
       final augmentResponse = await responses.next;
       expect(
           augmentResponse,
           '{"type":"AugmentResponse","value":'
-          '{"augmentations":[{"code":"int get x => 3;"}]}}');
+          '{"augmentations":[{"code":"int get x => 3;"}]},'
+          '"requestId":$requestId}');
     });
 
     test('sends query requests to host, sends reponse', () async {
@@ -73,23 +75,30 @@ void main() {
           '{"type":"MacroStartedRequest","value":'
           '{"macroDescription":{"runsInPhases":[3]}}}');
 
-      socket.writeln(json.encode(HostRequest.augmentRequest(AugmentRequest(
-          phase: 3, target: QualifiedName('package:foo/foo.dart#Foo')))));
+      var requestId = nextRequestId;
+      socket.writeln(json.encode(HostRequest.augmentRequest(
+          AugmentRequest(
+              phase: 3, target: QualifiedName('package:foo/foo.dart#Foo')),
+          id: nextRequestId)));
       final queryRequest = await responses.next;
       expect(
         queryRequest,
         '{"type":"QueryRequest","value":'
-        '{"query":{"target":"package:foo/foo.dart#Foo"}}}',
+        '{"query":{"target":"package:foo/foo.dart#Foo"}},'
+        '"id":$requestId}',
       );
 
-      socket.writeln(json.encode(Response.queryResponse(QueryResponse(
-          model: Model(uris: {'package:foo/foo.dart': Library()})))));
+      socket.writeln(json.encode(Response.queryResponse(
+          QueryResponse(
+              model: Model(uris: {'package:foo/foo.dart': Library()})),
+          requestId: requestId)));
 
       final augmentRequest = await responses.next;
       expect(
         augmentRequest,
         '{"type":"AugmentResponse","value":'
-        '{"augmentations":[{"code":"// {\\"uris\\":{\\"package:foo/foo.dart\\":{}}}"}]}}',
+        '{"augmentations":[{"code":"// {\\"uris\\":{\\"package:foo/foo.dart\\":{}}}"}]},'
+        '"requestId":$requestId}',
       );
     });
   });

pkgs/_macro_host/lib/macro_host.dart

@@ -67,7 +67,7 @@ class MacroHost {
     // TODO(davidmorgan): this just assumes the macro is running, actually
     // track macro lifecycle.
     final response = await macroServer.sendToMacro(
-        name, HostRequest.augmentRequest(request));
+        name, HostRequest.augmentRequest(request, id: nextRequestId));
     return response.asAugmentResponse;
   }
 }
@@ -88,12 +88,15 @@ class _HostService implements HostService {
         _macroPhases!.complete(request
             .asMacroStartedRequest.macroDescription.runsInPhases
             .toSet());
-        return Response.macroStartedResponse(MacroStartedResponse());
+        return Response.macroStartedResponse(MacroStartedResponse(),
+            requestId: request.id);
       case MacroRequestType.queryRequest:
         return Response.queryResponse(
-            await queryService.handle(request.asQueryRequest));
+            await queryService.handle(request.asQueryRequest),
+            requestId: request.id);
       default:
-        return Response.errorResponse(ErrorResponse(error: 'unsupported'));
+        return Response.errorResponse(ErrorResponse(error: 'unsupported'),
+            requestId: request.id);
     }
   }
 }

pkgs/_macro_server/test/macro_server_test.dart

@@ -36,8 +36,10 @@ class TestHostService implements HostService {
   Future<Response> handle(MacroRequest request) async {
     if (request.type == MacroRequestType.macroStartedRequest) {
       _macroStartedRequestsController.add(request.asMacroStartedRequest);
-      return Response.macroStartedResponse(MacroStartedResponse());
+      return Response.macroStartedResponse(MacroStartedResponse(),
+          requestId: request.id);
     }
-    return Response.errorResponse(ErrorResponse(error: 'unimplemented'));
+    return Response.errorResponse(ErrorResponse(error: 'unimplemented'),
+        requestId: request.id);
   }
 }

pkgs/dart_model/lib/src/dart_model.g.dart

@@ -1,5 +1,5 @@
 // This file is generated. To make changes edit schemas/*.schema.json
-// then run from the repo root: dart tool/model_generator/bin/main.dart
+// then run from the repo root: dart tool/dart_model_generator/bin/main.dart
 
 /// An augmentation to Dart code. TODO(davidmorgan): this is a placeholder.
 extension type Augmentation.fromJson(Map<String, Object?> node) {
@@ -165,12 +165,19 @@ enum StaticTypeType {
 }
 
 extension type StaticType.fromJson(Map<String, Object?> node) {
-  static StaticType neverType(NeverType neverType) =>
-      StaticType.fromJson({'type': 'NeverType', 'value': null});
+  static StaticType neverType(NeverType neverType) => StaticType.fromJson({
+        'type': 'NeverType',
+        'value': neverType,
+      });
   static StaticType nullableType(NullableType nullableType) =>
-      StaticType.fromJson({'type': 'NullableType', 'value': nullableType.node});
-  static StaticType voidType(VoidType voidType) =>
-      StaticType.fromJson({'type': 'VoidType', 'value': voidType.string});
+      StaticType.fromJson({
+        'type': 'NullableType',
+        'value': nullableType,
+      });
+  static StaticType voidType(VoidType voidType) => StaticType.fromJson({
+        'type': 'VoidType',
+        'value': voidType,
+      });
   StaticTypeType get type {
     switch (node['type'] as String) {
       case 'NeverType':

pkgs/macro_service/lib/src/macro_service.dart

@@ -18,3 +18,20 @@ abstract interface class MacroService {
   /// Handles [request].
   Future<Response> handle(HostRequest request);
 }
+
+/// Shared implementation of auto incrementing 32 bit IDs.
+///
+/// These roll back to 0 once it is greater than 2^32.
+///
+/// These are only unique to the process which generates the request,
+/// so for instance the host and macro services may generate conflicting ids
+/// and that is allowed.
+int get nextRequestId {
+  final next = _nextRequestId++;
+  if (_nextRequestId > 2 ^ 32) {
+    _nextRequestId = 0;
+  }
+  return next;
+}
+
+int _nextRequestId = 0;

pkgs/macro_service/lib/src/macro_service.g.dart

@@ -1,5 +1,5 @@
 // This file is generated. To make changes edit schemas/*.schema.json
-// then run from the repo root: dart tool/model_generator/bin/main.dart
+// then run from the repo root: dart tool/dart_model_generator/bin/main.dart
 
 import 'package:dart_model/dart_model.dart';
 
@@ -66,9 +66,15 @@ enum HostRequestType {
 }
 
 extension type HostRequest.fromJson(Map<String, Object?> node) {
-  static HostRequest augmentRequest(AugmentRequest augmentRequest) =>
-      HostRequest.fromJson(
-          {'type': 'AugmentRequest', 'value': augmentRequest.node});
+  static HostRequest augmentRequest(
+    AugmentRequest augmentRequest, {
+    required int id,
+  }) =>
+      HostRequest.fromJson({
+        'type': 'AugmentRequest',
+        'value': augmentRequest,
+        'id': id,
+      });
   HostRequestType get type {
     switch (node['type'] as String) {
       case 'AugmentRequest':
@@ -84,6 +90,9 @@ extension type HostRequest.fromJson(Map<String, Object?> node) {
     }
     return AugmentRequest.fromJson(node['value'] as Map<String, Object?>);
   }
+
+  /// The id of this request, must be returned in responses.
+  int get id => node['id'] as int;
 }
 
 /// Information about a macro that the macro provides to the host.
@@ -125,12 +134,23 @@ enum MacroRequestType {
 
 extension type MacroRequest.fromJson(Map<String, Object?> node) {
   static MacroRequest macroStartedRequest(
-          MacroStartedRequest macroStartedRequest) =>
-      MacroRequest.fromJson(
-          {'type': 'MacroStartedRequest', 'value': macroStartedRequest.node});
-  static MacroRequest queryRequest(QueryRequest queryRequest) =>
-      MacroRequest.fromJson(
-          {'type': 'QueryRequest', 'value': queryRequest.node});
+    MacroStartedRequest macroStartedRequest, {
+    required int id,
+  }) =>
+      MacroRequest.fromJson({
+        'type': 'MacroStartedRequest',
+        'value': macroStartedRequest,
+        'id': id,
+      });
+  static MacroRequest queryRequest(
+    QueryRequest queryRequest, {
+    required int id,
+  }) =>
+      MacroRequest.fromJson({
+        'type': 'QueryRequest',
+        'value': queryRequest,
+        'id': id,
+      });
   MacroRequestType get type {
     switch (node['type'] as String) {
       case 'MacroStartedRequest':
@@ -155,6 +175,9 @@ extension type MacroRequest.fromJson(Map<String, Object?> node) {
     }
     return QueryRequest.fromJson(node['value'] as Map<String, Object?>);
   }
+
+  /// The id of this request, must be returned in responses.
+  int get id => node['id'] as int;
 }
 
 /// Macro's query about the code it should augment.
@@ -189,17 +212,42 @@ enum ResponseType {
 }
 
 extension type Response.fromJson(Map<String, Object?> node) {
-  static Response augmentResponse(AugmentResponse augmentResponse) =>
-      Response.fromJson(
-          {'type': 'AugmentResponse', 'value': augmentResponse.node});
-  static Response errorResponse(ErrorResponse errorResponse) =>
-      Response.fromJson({'type': 'ErrorResponse', 'value': errorResponse.node});
+  static Response augmentResponse(
+    AugmentResponse augmentResponse, {
+    required int requestId,
+  }) =>
+      Response.fromJson({
+        'type': 'AugmentResponse',
+        'value': augmentResponse,
+        'requestId': requestId,
+      });
+  static Response errorResponse(
+    ErrorResponse errorResponse, {
+    required int requestId,
+  }) =>
+      Response.fromJson({
+        'type': 'ErrorResponse',
+        'value': errorResponse,
+        'requestId': requestId,
+      });
   static Response macroStartedResponse(
-          MacroStartedResponse macroStartedResponse) =>
-      Response.fromJson(
-          {'type': 'MacroStartedResponse', 'value': macroStartedResponse.node});
-  static Response queryResponse(QueryResponse queryResponse) =>
-      Response.fromJson({'type': 'QueryResponse', 'value': queryResponse.node});
+    MacroStartedResponse macroStartedResponse, {
+    required int requestId,
+  }) =>
+      Response.fromJson({
+        'type': 'MacroStartedResponse',
+        'value': macroStartedResponse,
+        'requestId': requestId,
+      });
+  static Response queryResponse(
+    QueryResponse queryResponse, {
+    required int requestId,
+  }) =>
+      Response.fromJson({
+        'type': 'QueryResponse',
+        'value': queryResponse,
+        'requestId': requestId,
+      });
   ResponseType get type {
     switch (node['type'] as String) {
       case 'AugmentResponse':
@@ -242,4 +290,7 @@ extension type Response.fromJson(Map<String, Object?> node) {
     }
     return QueryResponse.fromJson(node['value'] as Map<String, Object?>);
   }
+
+  /// The id of the [AugmentRequest] this is responding to.
+  int get requestId => node['requestId'] as int;
 }