From 1eab7ede9b3b4bf4ec0ceb89d4c8622689af778c Mon Sep 17 00:00:00 2001
From: Kyle Keesling <me@kylekeesling.com>
Date: Thu, 11 Jun 2026 11:58:05 -0400
Subject: [PATCH] fix(rails): make Action Cable handle_open/handle_close
 overrides public
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Rails 8.2 decoupled the Action Cable connection from the socket
(rails/rails#50979): ActionCable::Server::Socket now invokes
connection.handle_open and connection.handle_close from outside the
connection. sentry-rails' prepended overrides were private, so on Rails
main every cable connection raises

  NoMethodError (private method 'handle_open' called for an instance of
  ApplicationCable::Connection)

before the welcome message is sent — clients never receive pings or
broadcasts and reconnect in a loop. The error only reaches the Rails
logger (Sentry isn't initialized for the failing connection path), so
it fails silently.

On Rails < 8.2 these methods are only called internally on self, where
visibility doesn't matter, so making them public is safe everywhere.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 CHANGELOG.md                                       |  6 ++++++
 sentry-rails/lib/sentry/rails/action_cable.rb      |  9 +++++++--
 .../spec/sentry/rails/action_cable_spec.rb         | 14 ++++++++++++++
 3 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 17c74116f..b4f4b4bdc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+## Unreleased
+
+### Bug Fixes 🐛
+
+- (rails) Make Action Cable `handle_open`/`handle_close` overrides public so Rails 8.2's `ActionCable::Server::Socket` can invoke them ([rails/rails#50979](https://github.com/rails/rails/pull/50979)); the private overrides raised `NoMethodError` on every cable connection, killing all websocket traffic
+
 ## 6.6.2
 
 ### Bug Fixes 🐛
diff --git a/sentry-rails/lib/sentry/rails/action_cable.rb b/sentry-rails/lib/sentry/rails/action_cable.rb
index 222aab1b8..d2f8d61ad 100644
--- a/sentry-rails/lib/sentry/rails/action_cable.rb
+++ b/sentry-rails/lib/sentry/rails/action_cable.rb
@@ -57,8 +57,13 @@ def finish_transaction(transaction, status_code)
       end
 
       module Connection
-        private
-
+        # These overrides must stay public: Rails 8.2 decoupled the Action
+        # Cable connection from the socket (rails/rails#50979), and
+        # ActionCable::Server::Socket now invokes connection.handle_open and
+        # connection.handle_close from outside the connection. With private
+        # overrides every cable connection raises NoMethodError before the
+        # welcome message is sent. On older Rails versions these methods are
+        # only called internally, so public visibility is harmless there.
         def handle_open
           ErrorHandler.capture(self, transaction_name: "#{self.class.name}#connect") do
             super
diff --git a/sentry-rails/spec/sentry/rails/action_cable_spec.rb b/sentry-rails/spec/sentry/rails/action_cable_spec.rb
index e47ad2efa..9f7d74cf2 100644
--- a/sentry-rails/spec/sentry/rails/action_cable_spec.rb
+++ b/sentry-rails/spec/sentry/rails/action_cable_spec.rb
@@ -73,6 +73,20 @@ def disconnect
       transport.events = []
     end
 
+    describe "Connection method visibility" do
+      before do
+        make_basic_app
+      end
+
+      # Rails 8.2 (rails/rails#50979) invokes connection.handle_open and
+      # connection.handle_close from ActionCable::Server::Socket, outside the
+      # connection — private overrides break every cable connection there.
+      it "keeps handle_open and handle_close public" do
+        expect(Sentry::Rails::ActionCableExtensions::Connection.public_method_defined?(:handle_open)).to eq(true)
+        expect(Sentry::Rails::ActionCableExtensions::Connection.public_method_defined?(:handle_close)).to eq(true)
+      end
+    end
+
     describe "Connection" do
       before do
         make_basic_app