fix(spray): guard emitStats against cancelled context

spray/context_test.go

@@ -0,0 +1,74 @@
+package spray
+
+import (
+	"context"
+	"sync/atomic"
+	"testing"
+
+	"github.com/chainreactors/sdk/pkg/types"
+)
+
+// TestEmitStats_PanicAfterContextCancel reproduces the w3 pipeline panic.
+//
+// Scenario: consumer sets OnStats callback → context times out → consumer
+// shuts down (closes its channel) → SDK defer calls emitStats → callback
+// sends to closed channel → panic: send on closed channel.
+//
+// This test MUST panic before the fix and pass after.
+func TestEmitStats_PanicAfterContextCancel(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+
+	// Simulate pipeline's p.events channel
+	events := make(chan struct{}, 1)
+
+	c := &Context{
+		ctx: ctx,
+		statsHandler: func(stats types.Stats) {
+			events <- struct{}{} // this panics when events is closed
+		},
+	}
+
+	// Step 1: consumer abandons — context cancel + close channel
+	cancel()
+	close(events)
+
+	// Step 2: SDK defer fires emitStats after consumer is gone
+	panicked := true
+	func() {
+		defer func() {
+			if r := recover(); r == nil {
+				panicked = false
+			}
+		}()
+		c.emitStats(types.Stats{Engine: "spray"})
+	}()
+
+	if panicked {
+		t.Fatal("emitStats called statsHandler after context was cancelled, " +
+			"causing send on closed channel — this is the bug being fixed")
+	}
+}
+
+func TestEmitStats_NilContext(t *testing.T) {
+	var c *Context
+	c.emitStats(types.Stats{})
+}
+
+func TestEmitStats_NilHandler(t *testing.T) {
+	c := &Context{ctx: context.Background()}
+	c.emitStats(types.Stats{})
+}
+
+func TestEmitStats_ContextActive(t *testing.T) {
+	var called atomic.Bool
+	c := &Context{
+		ctx: context.Background(),
+		statsHandler: func(stats types.Stats) {
+			called.Store(true)
+		},
+	}
+	c.emitStats(types.Stats{Engine: "test"})
+	if !called.Load() {
+		t.Fatal("statsHandler should be called when context is active")
+	}
+}

spray/types.go

@@ -110,9 +110,10 @@ func (c *Context) SetStatsHandler(handler func(types.Stats)) *Context {
 }
 
 func (c *Context) emitStats(stats types.Stats) {
-	if c != nil && c.statsHandler != nil {
-		c.statsHandler(stats)
+	if c == nil || c.statsHandler == nil || c.ctx.Err() != nil {
+		return
 	}
+	c.statsHandler(stats)
 }
 
 // ========================================