Prevent crashes from get_main_hub when in trap context (#2510)

* Update CHANGELOG
* Prevent crashes from get_main_hub when in trap context

Author: solnic

CHANGELOG.md

@@ -10,6 +10,7 @@
 
 - Default to `internal_error` error type for OpenTelemetry spans [#2473](https://github.com/getsentry/sentry-ruby/pull/2473)
 - Improve `before_send` and `before_send_transaction`'s return value handling ([#2504](https://github.com/getsentry/sentry-ruby/pull/2504))
+- Fix a crash when calling `Sentry.get_main_hub` in a trap context ([#2510](https://github.com/getsentry/sentry-ruby/pull/2510))
 
 ### Internal
 

sentry-ruby/lib/sentry-ruby.rb

@@ -308,6 +308,9 @@ def csp_report_uri
     # @return [Hub]
     def get_main_hub
       MUTEX.synchronize { @main_hub }
+    rescue ThreadError
+      # In some rare cases this may be called in a trap context so we need to handle it gracefully
+      @main_hub
     end
 
     # Takes an instance of Sentry::Breadcrumb and stores it to the current active scope.

sentry-ruby/spec/sentry_spec.rb

@@ -70,6 +70,45 @@
         end
       end
     end
+
+    context "works within a trap context", when: { ruby_engine?: "ruby", ruby_version?: [:>=, "3.4"] } do
+      it "doesn't raise error when accessing main hub in trap context" do
+        read_pipe, write_pipe = IO.pipe
+
+        pid = fork do
+          described_class.init do |config|
+            config.dsn = Sentry::TestHelper::DUMMY_DSN
+          end
+
+          trap('HUP') do
+            hub = described_class.get_main_hub
+
+            write_pipe.write(hub.class.to_s)
+            write_pipe.close
+          end
+
+          Process.kill('HUP', Process.pid)
+        end
+
+        write_pipe.close
+
+        result = nil
+        retries = 0
+
+        while retries < 10
+          break if Process.wait(pid)
+
+          sleep 0.01
+
+          retries += 1
+        end
+
+        result = read_pipe.read
+        read_pipe.close
+
+        expect(result).to eq("Sentry::Hub")
+      end
+    end
   end
 
   describe "#clone_hub_to_current_thread" do

sentry-ruby/spec/spec_helper.rb

@@ -93,6 +93,10 @@ def self.rack_available?
   def self.ruby_version?(op, version)
     RUBY_VERSION.public_send(op, version)
   end
+
+  def self.ruby_engine?(engine)
+    RUBY_ENGINE == engine
+  end
 end
 
 def fixtures_root