fix: add logic to check for IAM RPC methods within the service before adding mixin to avoid generating duplicate methods

generator/gapic-generator-typescript/typescript/src/generator.ts

@@ -19,7 +19,7 @@ import * as yaml from 'js-yaml';
 import * as serializer from 'proto3-json-serializer';
 import protobuf from 'protobufjs';
 import type * as protos from '../../protos/index.js';
-import protoJson from '../../protos/protos.json' assert {type: 'json'};
+import protoJson from '../../protos/protos.json' with {type: 'json'};
 import * as url from 'url';
 import {API} from './schema/api.js';
 import {processTemplates} from './templater.js';
@@ -163,13 +163,30 @@ export class Generator {
       const content = fs.readFileSync(filename, 'utf8');
       const info = yaml.load(content) as ServiceYaml;
       this.serviceYaml = info;
-      const serviceMixins = [];
+      let serviceMixins: string[] = [];
       for (let i = 0; i < info.apis?.length || 0; i++) {
         const api = info.apis[i];
         for (const [, value] of Object.entries(api)) {
           serviceMixins.push(value);
         }
       }
+      if (serviceMixins.includes('google.iam.v1.IAMPolicy')) {
+        // Check if any of the services in the protos have SetIamPolicy, GetIamPolicy, or TestIamPermissions methods.
+        // If so, then remove the IAMPolicy mixin from the service yaml file to avoid duplicates.
+        const methods = API.getServiceMethods(
+          this.request.protoFile,
+          this.request.fileToGenerate,
+        );
+        if (
+          methods.has('SetIamPolicy') ||
+          methods.has('GetIamPolicy') ||
+          methods.has('TestIamPermissions')
+        ) {
+          serviceMixins = serviceMixins.filter(
+            m => m !== 'google.iam.v1.IAMPolicy',
+          );
+        }
+      }
       this.serviceYaml.apis = serviceMixins;
     }
     // override if needed

generator/gapic-generator-typescript/typescript/src/schema/api.ts

@@ -43,7 +43,7 @@
   handwrittenLayer?: boolean;
   legacyProtoLoad: boolean;
   restNumericEnums: boolean;
   documentationUri: any;
   newIssueUri: string;
   title?: string;
 
@@ -87,6 +87,28 @@
     return filteredProtos;
   }
 
+  static getServiceMethods(
+    fds: protos.google.protobuf.IFileDescriptorProto[],
+    filesToGenerate: string[],
+  ) {
+    const methods = new Set<string>();
+    const filesToGenerateSet = new Set(filesToGenerate);
+    for (const fd of fds) {
+      if (filesToGenerateSet.has(fd.name!) && fd.service) {
+        for (const service of fd.service) {
+          if (service.method) {
+            for (const method of service.method) {
+              if (method.name) {
+                methods.add(method.name);
+              }
+            }
+          }
+        }
+      }
+    }
+    return methods;
+  }
+
   constructor(
     fileDescriptors: protos.google.protobuf.IFileDescriptorProto[],
     packageName: string,