Only import SwiftProtobuf when WKTs are used as input/output

Sources/GRPCProtobufCodeGen/ProtobufCodeGenParser.swift

@@ -110,15 +110,26 @@ extension ProtobufCodeGenParser {
     var codeDependencies: [Dependency] = [
       Dependency(module: self.moduleNames.grpcProtobuf, accessLevel: .internal)
     ]
+
     // If there's a dependency on a bundled proto then add the SwiftProtobuf import.
     //
     // Importing SwiftProtobuf unconditionally results in warnings in the generated
     // code if access-levels are used on imports and no bundled protos are used.
-    let dependsOnBundledProto = file.dependencies.contains { descriptor in
-      SwiftProtobufInfo.isBundledProto(file: descriptor)
+    //
+    // The import is only needed if a bundled proto is used as the input or output type
+    // for an RPC. The file may have a dependency on a bundled proto without requiring
+    // the SwiftProtobuf import (e.g. a message depending on a bundle proto may be
+    // defined in the same file as the service, the dependency will be in the '.pb.swift'
+    // along with the message code).
+    let needsProtobufImport = file.services.contains { service in
+      service.methods.contains { method in
+        let inputIsBundled = SwiftProtobufInfo.isBundledProto(file: method.inputType.file)
+        let outputIsBundled = SwiftProtobufInfo.isBundledProto(file: method.outputType.file)
+        return inputIsBundled || outputIsBundled
+      }
     }
 
-    if dependsOnBundledProto {
+    if needsProtobufImport {
       let dependency = Dependency(
         module: self.moduleNames.swiftProtobuf,
         accessLevel: self.accessLevel

Tests/GRPCProtobufCodeGenTests/ProtobufCodeGenParserTests.swift

@@ -66,8 +66,7 @@ struct ProtobufCodeGenParserTests {
     @available(gRPCSwiftProtobuf 2.0, *)
     func dependencies() throws {
       let expected: [GRPCCodeGen.Dependency] = [
-        .init(module: "GRPCProtobuf", accessLevel: .internal),  // Always an internal import
-        .init(module: "SwiftProtobuf", accessLevel: .internal),
+        .init(module: "GRPCProtobuf", accessLevel: .internal)  // Always an internal import
       ]
       #expect(try self.codeGen.dependencies == expected)
     }

dev/protos/local/test-service.proto

@@ -3,7 +3,7 @@ syntax = "proto3";
 
 package test;
 
-// Using a WKT forces an "SwiftProtobuf" to be imported in generated code.
+// WKT isn't used in API generated by gRPC, so no import is expected.
 import "google/protobuf/any.proto";
 
 // Service docs.