Default throttle_time_ms to 0 if missing in ApiVersions response

src/protocol/requests/apiVersions/fixtures/v1_response_missing_throttle_time.json

@@ -0,0 +1 @@
+{"type":"Buffer","data":[0,0,0,0,0,34,0,0,0,0,0,3,0,1,0,0,0,5,0,2,0,0,0,2,0,3,0,0,0,4,0,4,0,0,0,0,0,5,0,0,0,0,0,6,0,0,0,3,0,7,0,1,0,1,0,8,0,0,0,3,0,9,0,0,0,3,0,10,0,0,0,1,0,11,0,0,0,2,0,12,0,0,0,1,0,13,0,0,0,1,0,14,0,0,0,1,0,15,0,0,0,1,0,16,0,0,0,1,0,17,0,0,0,0,0,18,0,0,0,1,0,19,0,0,0,2,0,20,0,0,0,1,0,21,0,0,0,0,0,22,0,0,0,0,0,23,0,0,0,0,0,24,0,0,0,0,0,25,0,0,0,0,0,26,0,0,0,0,0,27,0,0,0,0,0,28,0,0,0,0,0,29,0,0,0,0,0,30,0,0,0,0,0,31,0,0,0,0,0,32,0,0,0,0,0,33,0,0,0,0]}

src/protocol/requests/apiVersions/v1/response.js

@@ -24,10 +24,22 @@ const decode = async rawData => {
 
   failIfVersionNotSupported(errorCode)
 
+  const apiVersions = decoder.readArray(apiVersion)
+
+  /**
+   * The Java client defaults this value to 0 if not present,
+   * even though it is required in the protocol. This is to
+   * work around https://github.com/tulios/kafkajs/issues/491
+   *
+   * See:
+   * https://github.com/apache/kafka/blob/trunk/clients/src/main/java/org/apache/kafka/common/protocol/CommonFields.java#L23-L25
+   */
+  const throttleTime = decoder.canReadInt32() ? decoder.readInt32() : 0
+
   return {
     errorCode,
-    apiVersions: decoder.readArray(apiVersion),
-    throttleTime: decoder.readInt32(),
+    apiVersions,
+    throttleTime,
   }
 }
 

src/protocol/requests/apiVersions/v1/response.spec.js

@@ -48,6 +48,53 @@ describe('Protocol > Requests > ApiVersions > v1', () => {
     await expect(parse(data)).resolves.toBeTruthy()
   })
 
+  // https://github.com/tulios/kafkajs/issues/491
+  test('defaults throttle_time_ms if it is not provided in the response', async () => {
+    const data = await decode(
+      Buffer.from(require('../fixtures/v1_response_missing_throttle_time.json'))
+    )
+    expect(data).toEqual({
+      apiVersions: [
+        { apiKey: 0, maxVersion: 3, minVersion: 0 },
+        { apiKey: 1, maxVersion: 5, minVersion: 0 },
+        { apiKey: 2, maxVersion: 2, minVersion: 0 },
+        { apiKey: 3, maxVersion: 4, minVersion: 0 },
+        { apiKey: 4, maxVersion: 0, minVersion: 0 },
+        { apiKey: 5, maxVersion: 0, minVersion: 0 },
+        { apiKey: 6, maxVersion: 3, minVersion: 0 },
+        { apiKey: 7, maxVersion: 1, minVersion: 1 },
+        { apiKey: 8, maxVersion: 3, minVersion: 0 },
+        { apiKey: 9, maxVersion: 3, minVersion: 0 },
+        { apiKey: 10, maxVersion: 1, minVersion: 0 },
+        { apiKey: 11, maxVersion: 2, minVersion: 0 },
+        { apiKey: 12, maxVersion: 1, minVersion: 0 },
+        { apiKey: 13, maxVersion: 1, minVersion: 0 },
+        { apiKey: 14, maxVersion: 1, minVersion: 0 },
+        { apiKey: 15, maxVersion: 1, minVersion: 0 },
+        { apiKey: 16, maxVersion: 1, minVersion: 0 },
+        { apiKey: 17, maxVersion: 0, minVersion: 0 },
+        { apiKey: 18, maxVersion: 1, minVersion: 0 },
+        { apiKey: 19, maxVersion: 2, minVersion: 0 },
+        { apiKey: 20, maxVersion: 1, minVersion: 0 },
+        { apiKey: 21, maxVersion: 0, minVersion: 0 },
+        { apiKey: 22, maxVersion: 0, minVersion: 0 },
+        { apiKey: 23, maxVersion: 0, minVersion: 0 },
+        { apiKey: 24, maxVersion: 0, minVersion: 0 },
+        { apiKey: 25, maxVersion: 0, minVersion: 0 },
+        { apiKey: 26, maxVersion: 0, minVersion: 0 },
+        { apiKey: 27, maxVersion: 0, minVersion: 0 },
+        { apiKey: 28, maxVersion: 0, minVersion: 0 },
+        { apiKey: 29, maxVersion: 0, minVersion: 0 },
+        { apiKey: 30, maxVersion: 0, minVersion: 0 },
+        { apiKey: 31, maxVersion: 0, minVersion: 0 },
+        { apiKey: 32, maxVersion: 0, minVersion: 0 },
+        { apiKey: 33, maxVersion: 0, minVersion: 0 },
+      ],
+      errorCode: 0,
+      throttleTime: 0,
+    })
+  })
+
   test('throws KafkaJSProtocolError if the api is not supported', async () => {
     await expect(decode(unsupportedVersionResponse())).rejects.toThrow(
       /The version of API is not supported/