From d8cf925b097462f713d8e2ce62fe93d356ef47ba Mon Sep 17 00:00:00 2001
From: murgatroid99 <mlumish@google.com>
Date: Thu, 27 Feb 2020 09:50:35 -0800
Subject: [PATCH] Handle OK status differently when processing stream endings

---
 packages/grpc-js/src/call-stream.ts | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/packages/grpc-js/src/call-stream.ts b/packages/grpc-js/src/call-stream.ts
index 2d30c2a5..87c0a5a0 100644
--- a/packages/grpc-js/src/call-stream.ts
+++ b/packages/grpc-js/src/call-stream.ts
@@ -460,6 +460,13 @@ export class Http2CallStream implements Call {
       });
       stream.on('close', () => {
         this.trace('HTTP/2 stream closed with code ' + stream.rstCode);
+        /* If we have a final status with an OK status code, that means that
+         * we have received all of the messages and we have processed the
+         * trailers and the call completed successfully, so it doesn't matter
+         * how the stream ends after that */
+        if (this.finalStatus?.code === Status.OK) {
+          return;
+        }
         let code: Status;
         let details = '';
         switch (stream.rstCode) {
@@ -532,9 +539,16 @@ export class Http2CallStream implements Call {
     // The http2 stream could already have been destroyed if cancelWithStatus
     // is called in response to an internal http2 error.
     if (this.http2Stream !== null && !this.http2Stream.destroyed) {
-      /* TODO(murgatroid99): Determine if we want to send different RST_STREAM
-       * codes based on the status code */
-      this.http2Stream.close(NGHTTP2_CANCEL);
+      /* If the call has ended with an OK status, communicate that when closing
+       * the stream, partly to avoid a situation in which we detect an error
+       * RST_STREAM as a result after we have the status */
+      let code: number;
+      if (this.finalStatus?.code === Status.OK) {
+        code = http2.constants.NGHTTP2_NO_ERROR;
+      } else {
+        code = http2.constants.NGHTTP2_CANCEL;
+      }
+      this.http2Stream.close(code);
     }
   }