From ca4819ac6dbd3d99a1f20c1e08625020b8a48994 Mon Sep 17 00:00:00 2001
From: Eric Anderson <ejona@google.com>
Date: Thu, 6 Mar 2025 07:57:32 -0800
Subject: [PATCH] core: Apply ManagedChannelImpl's updateBalancingState()
 immediately

ffcc360ba adjusted updateBalancingState() to require being run within
the sync context. However, it still queued the work into the sync
context, which was unnecessary. This re-entering the sync context
unnecessarily delays the new state from being used.
---
 .../io/grpc/internal/ManagedChannelImpl.java  | 28 ++++++++-----------
 1 file changed, 11 insertions(+), 17 deletions(-)

diff --git a/core/src/main/java/io/grpc/internal/ManagedChannelImpl.java b/core/src/main/java/io/grpc/internal/ManagedChannelImpl.java
index 4581995447..dd4d0aef5b 100644
--- a/core/src/main/java/io/grpc/internal/ManagedChannelImpl.java
+++ b/core/src/main/java/io/grpc/internal/ManagedChannelImpl.java
@@ -1388,24 +1388,18 @@ final class ManagedChannelImpl extends ManagedChannel implements
       syncContext.throwIfNotInThisSynchronizationContext();
       checkNotNull(newState, "newState");
       checkNotNull(newPicker, "newPicker");
-      final class UpdateBalancingState implements Runnable {
-        @Override
-        public void run() {
-          if (LbHelperImpl.this != lbHelper || panicMode) {
-            return;
-          }
-          updateSubchannelPicker(newPicker);
-          // It's not appropriate to report SHUTDOWN state from lb.
-          // Ignore the case of newState == SHUTDOWN for now.
-          if (newState != SHUTDOWN) {
-            channelLogger.log(
-                ChannelLogLevel.INFO, "Entering {0} state with picker: {1}", newState, newPicker);
-            channelStateManager.gotoState(newState);
-          }
-        }
-      }
 
-      syncContext.execute(new UpdateBalancingState());
+      if (LbHelperImpl.this != lbHelper || panicMode) {
+        return;
+      }
+      updateSubchannelPicker(newPicker);
+      // It's not appropriate to report SHUTDOWN state from lb.
+      // Ignore the case of newState == SHUTDOWN for now.
+      if (newState != SHUTDOWN) {
+        channelLogger.log(
+            ChannelLogLevel.INFO, "Entering {0} state with picker: {1}", newState, newPicker);
+        channelStateManager.gotoState(newState);
+      }
     }
 
     @Override