fix: do not fail when decoding unknown error (#1077)

Fixes #1076. `google-gax` has no way to know of all possible error protos, so we'll just skip and ignore those that cannot be decoded.

src/googleError.ts

@@ -78,10 +78,19 @@ export class GoogleErrorDecoder {
 
     // google.rpc.Status contains an array of google.protobuf.Any
     // which need a special treatment
+    const details: Array<protobuf.Message> = [];
+    for (const detail of status.details) {
+      try {
+        const decodedDetail = this.decodeProtobufAny(detail);
+        details.push(decodedDetail);
+      } catch (err) {
+        // cannot decode detail, likely because of the unknown type - just skip it
+      }
+    }
     const result = {
       code: status.code,
       message: status.message,
-      details: status.details.map(detail => this.decodeProtobufAny(detail)),
+      details,
     };
     return result;
   }
@@ -98,6 +107,7 @@ export class GoogleErrorDecoder {
   decodeErrorFromBuffer(buffer: Buffer | ArrayBuffer): Error {
     return this.callErrorFromStatus(this.decodeRpcStatus(buffer));
   }
+
   // Decodes gRPC-fallback error which is an instance of google.rpc.Status.
   decodeRpcStatusDetails(
     bufferArr: Buffer[] | ArrayBuffer[]
@@ -108,10 +118,13 @@ export class GoogleErrorDecoder {
       const error_status = this.statusType.decode(
         uint8array
       ) as unknown as RpcStatus;
-      const status_details_array = error_status.details.map(detail =>
-        this.decodeProtobufAny(detail)
-      );
-      status.push(status_details_array[0]);
+      for (const detail of error_status.details) {
+        try {
+          status.push(this.decodeProtobufAny(detail));
+        } catch (err) {
+          // cannot decode detail, likely because of the unknown type - just skip it
+        }
+      }
     });
     return status;
   }

test/unit/googleError.ts

@@ -28,6 +28,25 @@ interface MyObj {
 }
 
 describe('gRPC-google error decoding', () => {
+  const fixtureName = path.resolve(
+    __dirname,
+    '..',
+    'fixtures',
+    'multipleErrors.json'
+  );
+  const protos_path = path.resolve(
+    __dirname,
+    '..',
+    '..',
+    'protos',
+    'google',
+    'rpc'
+  );
+  const root = protobuf.loadSync([
+    path.join(protos_path, 'error_details.proto'),
+    path.join(protos_path, 'status.proto'),
+  ]);
+
   it('decodes multiple errors', async () => {
     // example of when there are multiple errors available to be decoded
     const bufferArr = [] as Buffer[];
@@ -36,26 +55,7 @@ describe('gRPC-google error decoding', () => {
     const decoder = new GoogleErrorDecoder();
     const readFile = util.promisify(fs.readFile);
 
-    const fixtureName = path.resolve(
-      __dirname,
-      '..',
-      'fixtures',
-      'multipleErrors.json'
-    );
-    const protos_path = path.resolve(
-      __dirname,
-      '..',
-      '..',
-      'protos',
-      'google',
-      'rpc'
-    );
-
     const data = await readFile(fixtureName, 'utf8');
-    const root = protobuf.loadSync([
-      path.join(protos_path, 'error_details.proto'),
-      path.join(protos_path, 'status.proto'),
-    ]);
     const objs = JSON.parse(data) as MyObj[];
     for (const obj of objs) {
       const MessageType = root.lookupType(obj.type);
@@ -88,6 +88,33 @@ describe('gRPC-google error decoding', () => {
     assert.strictEqual(JSON.stringify(decodedError), JSON.stringify([]));
   });
 
+  it('DecodeRpcStatus does not fail when unknown type is encoded', () => {
+    const any = {type_url: 'noMatch', value: new Uint8Array()};
+    const status = {code: 3, message: 'test', details: [any]};
+    const Status = root.lookupType('google.rpc.Status');
+    const status_buffer = Status.encode(status).finish();
+    const decoder = new GoogleErrorDecoder();
+
+    const decodedError = decoder.decodeRpcStatus(status_buffer);
+
+    assert.strictEqual(
+      JSON.stringify(decodedError),
+      '{"code":3,"message":"test","details":[]}'
+    );
+  });
+
+  it('DecodeRpcStatusDetails does not fail when unknown type is encoded', () => {
+    const any = {type_url: 'noMatch', value: new Uint8Array()};
+    const status = {code: 3, message: 'test', details: [any]};
+    const Status = root.lookupType('google.rpc.Status');
+    const status_buffer = Status.encode(status).finish();
+    const decoder = new GoogleErrorDecoder();
+
+    const decodedError = decoder.decodeRpcStatusDetails([status_buffer]);
+
+    assert.strictEqual(JSON.stringify(decodedError), JSON.stringify([]));
+  });
+
   it('does not decode when unknown type is encoded in type_url', () => {
     // example of when error details' type_url doesn't match "type.googleapis.com"
     const decoder = new GoogleErrorDecoder();