From 7fc9eac6c923232317cf484995e075e69b6cf0ac Mon Sep 17 00:00:00 2001
From: water <672684719@qq.com>
Date: Sat, 1 Aug 2026 23:24:58 +0800
Subject: [PATCH] fix: prevent NPE in RetriableStream when cancel() races
 start() (#12964)

---
 .../io/grpc/internal/RetriableStream.java     | 23 +++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/core/src/main/java/io/grpc/internal/RetriableStream.java b/core/src/main/java/io/grpc/internal/RetriableStream.java
index 0c37a0beaca..4ddd24b3e93 100644
--- a/core/src/main/java/io/grpc/internal/RetriableStream.java
+++ b/core/src/main/java/io/grpc/internal/RetriableStream.java
@@ -392,6 +392,26 @@ public void runWith(Substream substream) {
   public final void start(ClientStreamListener listener) {
     masterListener = listener;
 
+    if (savedCloseMasterListenerReason != null) {
+      // cancel() was called before start() completed; close immediately with
+      // the already-saved reason.
+      listenerSerializeExecutor.execute(
+          new Runnable() {
+            @Override
+            public void run() {
+              if (masterListener == null || isClosed) {
+                return;
+              }
+              isClosed = true;
+              masterListener.closed(
+                  savedCloseMasterListenerReason.status,
+                  savedCloseMasterListenerReason.progress,
+                  savedCloseMasterListenerReason.metadata);
+            }
+          });
+      return;
+    }
+
     Status shutdownStatus = prestart();
 
     if (shutdownStatus != null) {
@@ -844,6 +864,9 @@ private void safeCloseMasterListener(Status status, RpcProgress progress, Metada
           new Runnable() {
             @Override
             public void run() {
+              if (masterListener == null) {
+                return;
+              }
               isClosed = true;
               masterListener.closed(status, progress, metadata);
             }