update how we calculate import prefixes

protoc_plugin/CHANGELOG.md

@@ -1,3 +1,10 @@
+## 22.4.0-wip
+
+* Update how we calculate import prefixes ([#1010]); import prefixes are now
+  unique per-library instead of being unique across all generated libraries.
+
+[#1010]: https://github.com/google/protobuf.dart/issues/1010
+
 ## 22.3.0
 
 * Update the generated code to improve readability and to better follow common

protoc_plugin/lib/src/base_type.dart

@@ -38,9 +38,9 @@ class BaseType {
   String get package => generator == null ? '' : generator!.package;
 
   /// The Dart expression to use for this type when in a different file.
-  String get prefixed => generator == null
+  String prefixed(FileGenerator fileGen) => generator == null
       ? unprefixed
-      : '${generator!.fileImportPrefix}.$unprefixed';
+      : '${generator!.importPrefix(context: fileGen)}.$unprefixed';
 
   /// Returns the name to use in generated code for this Dart type.
   ///
@@ -51,7 +51,7 @@ class BaseType {
   String getDartType(FileGenerator fileGen) =>
       (fileGen.protoFileUri == generator?.fileGen?.protoFileUri)
           ? unprefixed
-          : prefixed;
+          : prefixed(fileGen);
 
   String getRepeatedDartType(FileGenerator fileGen) =>
       '$protobufImportPrefix.PbList<${getDartType(fileGen)}>';

protoc_plugin/lib/src/code_generator.dart

@@ -19,9 +19,8 @@ import 'options.dart';
 import 'output_config.dart';
 
 abstract class ProtobufContainer {
-  // Internal map of proto file URIs to prefix aliases to resolve name conflicts
-  static final _importPrefixes = <String, String>{};
-  static int _idx = 0;
+  // A map of proto file paths to import prefix aliases.
+  final Map<String, String> _prefixes = {};
 
   String get package;
   String? get classname;
@@ -40,22 +39,17 @@ abstract class ProtobufContainer {
   /// This exists because names from protoc come like this.
   String get dottedName => '.$fullName';
 
-  String get fileImportPrefix => _getFileImportPrefix();
-
   String get binaryDescriptorName =>
       '${lowerCaseFirstLetter(classname!)}Descriptor';
 
-  String _getFileImportPrefix() {
-    final path = fileGen!.protoFileUri.toString();
-    if (_importPrefixes.containsKey(path)) {
-      return _importPrefixes[path]!;
-    }
-    final alias = '\$$_idx';
-    _importPrefixes[path] = alias;
-    _idx++;
-    return alias;
+  String importPrefix({required FileGenerator context}) {
+    final protoFilePath = fileGen!.protoFileUri.toString();
+    return context._calculateImportPrefix(protoFilePath);
   }
 
+  String _calculateImportPrefix(String protoImportPath) =>
+      _prefixes.putIfAbsent(protoImportPath, () => '\$${_prefixes.length}');
+
   /// The generator of the .pb.dart file defining this entity.
   ///
   /// (Represents the .pb.dart file that we need to import in order to use it.)

protoc_plugin/lib/src/enum_generator.dart

@@ -88,13 +88,15 @@ class EnumGenerator extends ProtobufContainer {
   }
 
   /// Returns a const expression that evaluates to the JSON for this message.
-  /// [usage] represents the .pb.dart file where the expression will be used.
-  String getJsonConstant(FileGenerator usage) {
+  ///
+  /// [context] represents the .pb.dart file where the expression will be used.
+  String getJsonConstant(FileGenerator context) {
     final name = '$classname\$json';
-    if (usage.protoFileUri == fileGen!.protoFileUri) {
+    if (context.protoFileUri == fileGen!.protoFileUri) {
       return name;
     }
-    return '$fileImportPrefix.$name';
+
+    return '${importPrefix(context: context)}.$name';
   }
 
   static const int _enumValueTag = 2;

protoc_plugin/lib/src/file_generator.dart

@@ -671,14 +671,16 @@ class FileGenerator extends ProtobufContainer {
   void _addImport(ImportWriter importWriter, OutputConfiguration config,
       FileGenerator target, String ext) {
     final url = config.resolveImport(target.protoFileUri, protoFileUri, ext);
+    final import = url.toString();
 
     // .pb.dart files should always be prefixed -- the protoFileUri check will
     // evaluate to true not just for the main .pb.dart file based off the proto
     // file, but also for the .pbserver.dart, .pbgrpc.dart files.
-    if ((ext == '.pb.dart') || protoFileUri != target.protoFileUri) {
-      importWriter.addImport(url.toString(), prefix: target.fileImportPrefix);
+    if (ext == '.pb.dart' || protoFileUri != target.protoFileUri) {
+      importWriter.addImport(import,
+          prefix: target.importPrefix(context: fileGen));
     } else {
-      importWriter.addImport(url.toString());
+      importWriter.addImport(import);
     }
   }
 

protoc_plugin/lib/src/gen/google/protobuf/compiler/plugin.pb.dart

@@ -15,7 +15,7 @@ import 'dart:core' as $core;
 import 'package:fixnum/fixnum.dart' as $fixnum;
 import 'package:protobuf/protobuf.dart' as $pb;
 
-import '../descriptor.pb.dart' as $2;
+import '../descriptor.pb.dart' as $0;
 
 export 'package:protobuf/protobuf.dart' show GeneratedMessageGenericExtensions;
 
@@ -121,8 +121,8 @@ class CodeGeneratorRequest extends $pb.GeneratedMessage {
     $core.Iterable<$core.String>? fileToGenerate,
     $core.String? parameter,
     Version? compilerVersion,
-    $core.Iterable<$2.FileDescriptorProto>? protoFile,
-    $core.Iterable<$2.FileDescriptorProto>? sourceFileDescriptors,
+    $core.Iterable<$0.FileDescriptorProto>? protoFile,
+    $core.Iterable<$0.FileDescriptorProto>? sourceFileDescriptors,
   }) {
     final result = create();
     if (fileToGenerate != null) result.fileToGenerate.addAll(fileToGenerate);
@@ -152,12 +152,12 @@ class CodeGeneratorRequest extends $pb.GeneratedMessage {
     ..aOS(2, _omitFieldNames ? '' : 'parameter')
     ..aOM<Version>(3, _omitFieldNames ? '' : 'compilerVersion',
         subBuilder: Version.create)
-    ..pc<$2.FileDescriptorProto>(
+    ..pc<$0.FileDescriptorProto>(
         15, _omitFieldNames ? '' : 'protoFile', $pb.PbFieldType.PM,
-        subBuilder: $2.FileDescriptorProto.create)
-    ..pc<$2.FileDescriptorProto>(
+        subBuilder: $0.FileDescriptorProto.create)
+    ..pc<$0.FileDescriptorProto>(
         17, _omitFieldNames ? '' : 'sourceFileDescriptors', $pb.PbFieldType.PM,
-        subBuilder: $2.FileDescriptorProto.create);
+        subBuilder: $0.FileDescriptorProto.create);
 
   @$core.Deprecated('See https://github.com/google/protobuf.dart/issues/998.')
   CodeGeneratorRequest clone() =>
@@ -229,13 +229,13 @@ class CodeGeneratorRequest extends $pb.GeneratedMessage {
   /// Type names of fields and extensions in the FileDescriptorProto are always
   /// fully qualified.
   @$pb.TagNumber(15)
-  $pb.PbList<$2.FileDescriptorProto> get protoFile => $_getList(3);
+  $pb.PbList<$0.FileDescriptorProto> get protoFile => $_getList(3);
 
   /// File descriptors with all options, including source-retention options.
   /// These descriptors are only provided for the files listed in
   /// files_to_generate.
   @$pb.TagNumber(17)
-  $pb.PbList<$2.FileDescriptorProto> get sourceFileDescriptors => $_getList(4);
+  $pb.PbList<$0.FileDescriptorProto> get sourceFileDescriptors => $_getList(4);
 }
 
 /// Represents a single generated file.
@@ -244,7 +244,7 @@ class CodeGeneratorResponse_File extends $pb.GeneratedMessage {
     $core.String? name,
     $core.String? insertionPoint,
     $core.String? content,
-    $2.GeneratedCodeInfo? generatedCodeInfo,
+    $0.GeneratedCodeInfo? generatedCodeInfo,
   }) {
     final result = create();
     if (name != null) result.name = name;
@@ -271,8 +271,8 @@ class CodeGeneratorResponse_File extends $pb.GeneratedMessage {
     ..aOS(1, _omitFieldNames ? '' : 'name')
     ..aOS(2, _omitFieldNames ? '' : 'insertionPoint')
     ..aOS(15, _omitFieldNames ? '' : 'content')
-    ..aOM<$2.GeneratedCodeInfo>(16, _omitFieldNames ? '' : 'generatedCodeInfo',
-        subBuilder: $2.GeneratedCodeInfo.create)
+    ..aOM<$0.GeneratedCodeInfo>(16, _omitFieldNames ? '' : 'generatedCodeInfo',
+        subBuilder: $0.GeneratedCodeInfo.create)
     ..hasRequiredFields = false;
 
   @$core.Deprecated('See https://github.com/google/protobuf.dart/issues/998.')
@@ -379,15 +379,15 @@ class CodeGeneratorResponse_File extends $pb.GeneratedMessage {
   /// point is used, this information will be appropriately offset and inserted
   /// into the code generation metadata for the generated files.
   @$pb.TagNumber(16)
-  $2.GeneratedCodeInfo get generatedCodeInfo => $_getN(3);
+  $0.GeneratedCodeInfo get generatedCodeInfo => $_getN(3);
   @$pb.TagNumber(16)
-  set generatedCodeInfo($2.GeneratedCodeInfo value) => $_setField(16, value);
+  set generatedCodeInfo($0.GeneratedCodeInfo value) => $_setField(16, value);
   @$pb.TagNumber(16)
   $core.bool hasGeneratedCodeInfo() => $_has(3);
   @$pb.TagNumber(16)
   void clearGeneratedCodeInfo() => $_clearField(16);
   @$pb.TagNumber(16)
-  $2.GeneratedCodeInfo ensureGeneratedCodeInfo() => $_ensure(3);
+  $0.GeneratedCodeInfo ensureGeneratedCodeInfo() => $_ensure(3);
 }
 
 /// The plugin writes an encoded CodeGeneratorResponse to stdout.

protoc_plugin/lib/src/grpc_generator.dart

@@ -97,14 +97,15 @@ class GrpcServiceGenerator {
   /// Returns the Dart class name to use for a message type.
   ///
   /// Throws an exception if it can't be resolved.
-  String _getDartClassName(String fqname) {
-    final mg = _deps[fqname];
-    if (mg == null) {
-      final location = _undefinedDeps[fqname];
+  String _getDartClassName(String fqName) {
+    final generator = _deps[fqName];
+    if (generator == null) {
+      final location = _undefinedDeps[fqName];
       // TODO(nichite): Throw more actionable error.
-      throw 'FAILURE: Unknown type reference ($fqname) for $location';
+      throw 'FAILURE: Unknown type reference ($fqName) for $location';
     }
-    return '${mg.fileImportPrefix}.${mg.classname}';
+
+    return '${generator.importPrefix(context: fileGen)}.${generator.classname}';
   }
 
   void generate(IndentingWriter out) {

protoc_plugin/lib/src/message_generator.dart

@@ -160,13 +160,14 @@ class MessageGenerator extends ProtobufContainer {
   }
 
   /// Returns a const expression that evaluates to the JSON for this message.
-  /// [usage] represents the .pb.dart file where the expression will be used.
-  String getJsonConstant(FileGenerator usage) {
+  ///
+  /// [context] represents the .pb.dart file where the expression will be used.
+  String getJsonConstant(FileGenerator context) {
     final name = '$classname\$json';
-    if (usage.protoFileUri == fileGen.protoFileUri) {
+    if (context.protoFileUri == fileGen.protoFileUri) {
       return name;
     }
-    return '$fileImportPrefix.$name';
+    return '${importPrefix(context: context)}.$name';
   }
 
   /// Adds all mixins used in this message and any submessages.

protoc_plugin/lib/src/service_generator.dart

@@ -14,18 +14,18 @@ class ServiceGenerator {
   ///
   /// The key is the fully qualified name with a leading '.'.
   /// Populated by [resolve].
-  final _deps = <String, MessageGenerator>{};
+  final Map<String, MessageGenerator> _deps = {};
 
   /// The message types needed transitively by this service.
   ///
   /// The key is the fully qualified name with a leading '.'.
   /// Populated by [resolve].
-  final _transitiveDeps = <String, MessageGenerator>{};
+  final Map<String, MessageGenerator> _transitiveDeps = {};
 
   /// Maps each undefined type to a string describing its location.
   ///
   /// Populated by [resolve].
-  final _undefinedDeps = <String, String>{};
+  final Map<String, String> _undefinedDeps = {};
 
   final String classname;
 
@@ -118,16 +118,18 @@ class ServiceGenerator {
   /// should be prefixed unless the target file is the main file (the client
   /// generator calls this method). Otherwise, prefix everything.
   String _getDartClassName(String fqname, {bool forMainFile = false}) {
-    final mg = _deps[fqname];
-    if (mg == null) {
+    final generator = _deps[fqname];
+    if (generator == null) {
       final location = _undefinedDeps[fqname];
       throw 'FAILURE: Unknown type reference ($fqname) for $location';
     }
-    if (forMainFile && fileGen.protoFileUri == mg.fileGen.protoFileUri) {
+
+    if (forMainFile && fileGen.protoFileUri == generator.fileGen.protoFileUri) {
       // If it's the same file, we import it without using "as".
-      return mg.classname;
+      return generator.classname;
     }
-    return '${mg.fileImportPrefix}.${mg.classname}';
+
+    return '${generator.importPrefix(context: fileGen)}.${generator.classname}';
   }
 
   List<MethodDescriptorProto> get _methodDescriptors => _descriptor.method;

protoc_plugin/pubspec.yaml

@@ -1,5 +1,5 @@
 name: protoc_plugin
-version: 22.3.0
+version: 22.4.0-wip
 description: A protobuf protoc compiler plugin used to generate Dart code.
 repository: https://github.com/google/protobuf.dart/tree/master/protoc_plugin
 

protoc_plugin/test/goldens/imports.pb

@@ -14,8 +14,8 @@ import 'dart:core' as $core;
 
 import 'package:protobuf/protobuf.dart' as $pb;
 
-import 'package1.pb.dart' as $1;
-import 'package2.pb.dart' as $2;
+import 'package1.pb.dart' as $0;
+import 'package2.pb.dart' as $1;
 
 export 'package:protobuf/protobuf.dart' show GeneratedMessageGenericExtensions;
 
@@ -29,8 +29,8 @@ class M extends $pb.GeneratedMessage {
 
   static final $pb.BuilderInfo _i = $pb.BuilderInfo(_omitMessageNames ? '' : 'M', createEmptyInstance: create)
     ..aOM<M>(1, _omitFieldNames ? '' : 'm', subBuilder: M.create)
-    ..aOM<$1.M>(2, _omitFieldNames ? '' : 'm1', subBuilder: $1.M.create)
-    ..aOM<$2.M>(3, _omitFieldNames ? '' : 'm2', subBuilder: $2.M.create)
+    ..aOM<$0.M>(2, _omitFieldNames ? '' : 'm1', subBuilder: $0.M.create)
+    ..aOM<$1.M>(3, _omitFieldNames ? '' : 'm2', subBuilder: $1.M.create)
     ..hasRequiredFields = false
   ;
 
@@ -63,26 +63,26 @@ class M extends $pb.GeneratedMessage {
   M ensureM() => $_ensure(0);
 
   @$pb.TagNumber(2)
-  $1.M get m1 => $_getN(1);
+  $0.M get m1 => $_getN(1);
   @$pb.TagNumber(2)
-  set m1($1.M value) => $_setField(2, value);
+  set m1($0.M value) => $_setField(2, value);
   @$pb.TagNumber(2)
   $core.bool hasM1() => $_has(1);
   @$pb.TagNumber(2)
   void clearM1() => $_clearField(2);
   @$pb.TagNumber(2)
-  $1.M ensureM1() => $_ensure(1);
+  $0.M ensureM1() => $_ensure(1);
 
   @$pb.TagNumber(3)
-  $2.M get m2 => $_getN(2);
+  $1.M get m2 => $_getN(2);
   @$pb.TagNumber(3)
-  set m2($2.M value) => $_setField(3, value);
+  set m2($1.M value) => $_setField(3, value);
   @$pb.TagNumber(3)
   $core.bool hasM2() => $_has(2);
   @$pb.TagNumber(3)
   void clearM2() => $_clearField(3);
   @$pb.TagNumber(3)
-  $2.M ensureM2() => $_ensure(2);
+  $1.M ensureM2() => $_ensure(2);
 }