fix(logging): prevent log errors from crashing main thread

CHANGELOG.md

@@ -4,6 +4,10 @@
 
 - Include otel as custom sampling context ([2683](https://github.com/getsentry/sentry-ruby/pull/2683))
 
+### Fixes
+
+- Prevent logging from crashing main thread ([2795](https://github.com/getsentry/sentry-ruby/pull/2795))
+
 ## 6.1.2
 
 ### Fixes

sentry-ruby/lib/sentry/log_event_buffer.rb

@@ -65,11 +65,18 @@ def size
       @pending_events.size
     end
 
+    def clear!
+      @pending_events.clear
+    end
+
     private
 
     def send_events
       @client.send_logs(@pending_events)
-      @pending_events.clear
+    rescue => e
+      log_debug("[LogEventBuffer] Failed to send logs: #{e.message}")
+    ensure
+      clear!
     end
   end
 end

sentry-ruby/spec/sentry/log_event_buffer_spec.rb

@@ -74,4 +74,61 @@
       expect(log_event_buffer).to be_empty
     end
   end
+
+  describe "error handling" do
+    let(:max_log_events) { 3 }
+
+    let(:error) { Errno::ECONNREFUSED.new("Connection refused") }
+
+    context "when send_logs raises an exception" do
+      before do
+        allow(client).to receive(:send_logs).and_raise(error)
+      end
+
+      it "does not propagate exception from add_event when buffer is full" do
+        expect {
+          3.times { log_event_buffer.add_event(log_event) }
+        }.not_to raise_error
+      end
+
+      it "does not propagate exception from flush" do
+        2.times { log_event_buffer.add_event(log_event) }
+
+        expect {
+          log_event_buffer.flush
+        }.not_to raise_error
+      end
+
+      it "logs the error to sdk_logger" do
+        3.times { log_event_buffer.add_event(log_event) }
+
+        expect(string_io.string).to include("Failed to send logs")
+      end
+
+      it "clears the buffer after a failed send to avoid memory buildup" do
+        3.times { log_event_buffer.add_event(log_event) }
+
+        expect(log_event_buffer).to be_empty
+      end
+    end
+
+    context "when background thread encounters an error" do
+      let(:max_log_events) { 100 }
+
+      before do
+        allow(client).to receive(:send_logs).and_raise(error)
+      end
+
+      it "keeps the background thread alive after an error" do
+        log_event_buffer.add_event(log_event)
+        log_event_buffer.start
+
+        thread = log_event_buffer.instance_variable_get(:@thread)
+
+        expect(thread).to be_alive
+        expect { log_event_buffer.flush }.not_to raise_error
+        expect(thread).to be_alive
+      end
+    end
+  end
 end