Expose HTTP errors that are not meant to be retried (nodejs#2496)

* test: failing test to show http response not passed through

* fix: pass through requests that do not expect a retry

* refactor: cleanup

Author: MzUgM

lib/handler/RetryHandler.js

@@ -172,13 +172,22 @@ class RetryHandler {
     this.retryCount += 1
 
     if (statusCode >= 300) {
-      this.abort(
-        new RequestRetryError('Request failed', statusCode, {
-          headers,
-          count: this.retryCount
-        })
-      )
-      return false
+      if (this.retryOpts.statusCodes.includes(statusCode) === false) {
+        return this.handler.onHeaders(
+          statusCode,
+          rawHeaders,
+          resume,
+          statusMessage
+        )
+      } else {
+        this.abort(
+          new RequestRetryError('Request failed', statusCode, {
+            headers,
+            count: this.retryCount
+          })
+        )
+        return false
+      }
     }
 
     // Checkpoint for resume from where we left it

test/retry-handler.js

@@ -620,3 +620,72 @@ tap.test('retrying a request with a body', t => {
     )
   })
 })
+
+tap.test('should not error if request is not meant to be retried', t => {
+  const server = createServer()
+  server.on('request', (req, res) => {
+    res.writeHead(400)
+    res.end('Bad request')
+  })
+
+  t.plan(3)
+
+  const dispatchOptions = {
+    retryOptions: {
+      method: 'GET',
+      path: '/',
+      headers: {
+        'content-type': 'application/json'
+      }
+    }
+  }
+
+  server.listen(0, () => {
+    const client = new Client(`http://localhost:${server.address().port}`)
+    const chunks = []
+    const handler = new RetryHandler(dispatchOptions, {
+      dispatch: client.dispatch.bind(client),
+      handler: {
+        onConnect () {
+          t.pass()
+        },
+        onBodySent () {
+          t.pass()
+        },
+        onHeaders (status, _rawHeaders, resume, _statusMessage) {
+          t.equal(status, 400)
+          return true
+        },
+        onData (chunk) {
+          chunks.push(chunk)
+          return true
+        },
+        onComplete () {
+          t.equal(Buffer.concat(chunks).toString('utf-8'), 'Bad request')
+        },
+        onError (err) {
+          console.log({ err })
+          t.fail()
+        }
+      }
+    })
+
+    t.teardown(async () => {
+      await client.close()
+      server.close()
+
+      await once(server, 'close')
+    })
+
+    client.dispatch(
+      {
+        method: 'GET',
+        path: '/',
+        headers: {
+          'content-type': 'application/json'
+        }
+      },
+      handler
+    )
+  })
+})