1 files changed, 54 insertions, 0 deletions
diff --git a/src/net/http/httptest/server_test.go b/src/net/http/httptest/server_test.go
index 39568b358c..5313f65456 100644
--- a/src/net/http/httptest/server_test.go
+++ b/src/net/http/httptest/server_test.go
@@ -9,6 +9,7 @@ import (
 	"io"
 	"net"
 	"net/http"
+	"sync"
 	"testing"
 )
 
@@ -203,6 +204,59 @@ func TestServerZeroValueClose(t *testing.T) {
 	ts.Close() // tests that it doesn't panic
 }
 
+// Issue 51799: test hijacking a connection and then closing it
+// concurrently with closing the server.
+func TestCloseHijackedConnection(t *testing.T) {
+	hijacked := make(chan net.Conn)
+	ts := NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		defer close(hijacked)
+		hj, ok := w.(http.Hijacker)
+		if !ok {
+			t.Fatal("failed to hijack")
+		}
+		c, _, err := hj.Hijack()
+		if err != nil {
+			t.Fatal(err)
+		}
+		hijacked <- c
+	}))
+
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		req, err := http.NewRequest("GET", ts.URL, nil)
+		if err != nil {
+			t.Log(err)
+		}
+		// Use a client not associated with the Server.
+		var c http.Client
+		resp, err := c.Do(req)
+		if err != nil {
+			t.Log(err)
+			return
+		}
+		resp.Body.Close()
+	}()
+
+	wg.Add(1)
+	conn := <-hijacked
+	go func(conn net.Conn) {
+		defer wg.Done()
+		// Close the connection and then inform the Server that
+		// we closed it.
+		conn.Close()
+		ts.Config.ConnState(conn, http.StateClosed)
+	}(conn)
+
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		ts.Close()
+	}()
+	wg.Wait()
+}
+
 func TestTLSServerWithHTTP2(t *testing.T) {
 	modes := []struct {
 		name      string