ignore unused_imports for json files (#1013)

Author: devoncarew

protoc_plugin/CHANGELOG.md

@@ -2,6 +2,7 @@
 
 * Update how we calculate import prefixes ([#1010]); import prefixes are now
   unique per-library instead of being unique across all generated libraries.
+* Ignore `unused_import` diagnostics for `*.pbjson.dart` files.
 
 [#1010]: https://github.com/google/protobuf.dart/issues/1010
 

protoc_plugin/lib/src/file_generator.dart

@@ -237,6 +237,7 @@ class FileGenerator extends ProtobufContainer {
     final files = [
       makeFile('.pb.dart', mainWriter.toString()),
       if (enumWriter != null) makeFile('.pbenum.dart', enumWriter.toString()),
+      // TODO(devoncarew): Consider not emitting empty json files.
       makeFile('.pbjson.dart', generateJsonFile(config)),
     ];
 
@@ -269,8 +270,8 @@ class FileGenerator extends ProtobufContainer {
   IndentingWriter generateMainFile(
       [OutputConfiguration config = const DefaultOutputConfiguration()]) {
     if (!_linked) throw StateError('not linked');
-    final out = makeWriter();
 
+    final out = makeWriter();
     writeMainHeader(out, config);
 
     // Generate code.
@@ -516,6 +517,7 @@ class FileGenerator extends ProtobufContainer {
   String generateGrpcFile(
       [OutputConfiguration config = const DefaultOutputConfiguration()]) {
     if (!_linked) throw StateError('not linked');
+
     final out = makeWriter();
     _writeHeading(out);
 
@@ -578,8 +580,9 @@ class FileGenerator extends ProtobufContainer {
   String generateJsonFile(
       [OutputConfiguration config = const DefaultOutputConfiguration()]) {
     if (!_linked) throw StateError('not linked');
+
     final out = makeWriter();
-    _writeHeading(out);
+    _writeHeading(out, extraIgnores: {'unused_import'});
 
     final importWriter = ImportWriter();
     importWriter.addImport(_convertImportUrl, prefix: _convertImportPrefix);

protoc_plugin/test/goldens/oneMessage.pbjson

@@ -8,7 +8,7 @@
 // ignore_for_file: constant_identifier_names
 // ignore_for_file: curly_braces_in_flow_control_structures
 // ignore_for_file: deprecated_member_use_from_same_package, library_prefixes
-// ignore_for_file: non_constant_identifier_names
+// ignore_for_file: non_constant_identifier_names, unused_import
 
 import 'dart:convert' as $convert;
 import 'dart:core' as $core;

protoc_plugin/test/goldens/serviceGenerator.pb.json

@@ -8,7 +8,7 @@
 // ignore_for_file: constant_identifier_names
 // ignore_for_file: curly_braces_in_flow_control_structures
 // ignore_for_file: deprecated_member_use_from_same_package, library_prefixes
-// ignore_for_file: non_constant_identifier_names
+// ignore_for_file: non_constant_identifier_names, unused_import
 
 import 'dart:convert' as $convert;
 import 'dart:core' as $core;

protoc_plugin/test/goldens/topLevelEnum.pbjson

@@ -8,7 +8,7 @@
 // ignore_for_file: constant_identifier_names
 // ignore_for_file: curly_braces_in_flow_control_structures
 // ignore_for_file: deprecated_member_use_from_same_package, library_prefixes
-// ignore_for_file: non_constant_identifier_names
+// ignore_for_file: non_constant_identifier_names, unused_import
 
 import 'dart:convert' as $convert;
 import 'dart:core' as $core;