Function TestCompactionInputConcurrent

pkg/session/session_race_test.go:32–51

TestCompactionInputConcurrent pins the data-race fix for the compactor: CompactionInput must read s.Messages under s.mu (via snapshotItems) so it stays safe against concurrent AddMessage and ApplyCompaction calls. Run with -race; without the lock the slice header read aliases the live backing array

(t *testing.T)

// header read aliases the live backing array and the race detector
// flags the AddMessage append.
func TestCompactionInputConcurrent(t *testing.T) {
	t.Parallel()

	s := New()
	var wg sync.WaitGroup
	for range 100 {
		wg.Go(func() {
			s.AddMessage(&Message{Message: chat.Message{Role: chat.MessageRoleUser, Content: "u"}})
		})
		wg.Go(func() {
			_, _ = s.CompactionInput()
		})
	}
	// One concurrent ApplyCompaction-shaped write to exercise the same
	// lock from a writer that also bumps the cumulative token counts.
	wg.Go(func() {
		s.ApplyCompaction(0, 0, Item{Summary: "snap"})
	})
	wg.Wait()
}