From 7f67e19b2f26fe076013b9acab252d4b3d0e33e8 Mon Sep 17 00:00:00 2001
From: Rob Shakir <robjs@google.com>
Date: Thu, 21 May 2026 15:18:39 +0000
Subject: [PATCH] Add test for repeated session parameters

This test verifies that the server returns FailedPrecondition when a client sends SessionParameters more than once on a stream.
---
 compliance/compliance.go | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/compliance/compliance.go b/compliance/compliance.go
index 4636023..6bb45aa 100644
--- a/compliance/compliance.go
+++ b/compliance/compliance.go
@@ -156,6 +156,11 @@ var (
 			Fn:        ModifyConnectionSinglePrimaryPreserve,
 			ShortName: "Modify RPC Connection with invalid persist/redundancy parameters",
 		},
+	}, {
+		In: Test{
+			Fn:        ModifyConnectionRepeatedSessionParameters,
+			ShortName: "Modify RPC Connection with repeated SessionParameters",
+		},
 	}, {
 		In: Test{
 			Fn:        InvalidElectionIDAndAFTOperation,
@@ -785,6 +790,37 @@ func InvalidParamsAndAFTOperation(c *fluent.GRIBIClient, t testing.TB, _ ...Test
 	chk.HasRecvClientErrorWithStatus(t, err, want, chk.IgnoreDetails())
 }
 
+// ModifyConnectionRepeatedSessionParameters validates that the server returns an error when a client
+// specifies session parameters more than once on a stream.
+func ModifyConnectionRepeatedSessionParameters(c *fluent.GRIBIClient, t testing.TB, _ ...TestOpt) {
+	defer electionID.Inc()
+	c.Connection().WithRedundancyMode(fluent.ElectedPrimaryClient).WithPersistence().WithInitialElectionID(electionID.Load(), 0)
+	c.Start(context.Background(), t)
+	defer c.Stop(t)
+
+	c.StartSending(context.Background(), t)
+
+	// Inject a second session parameters message.
+	c.Modify().InjectRequest(t, &spb.ModifyRequest{
+		Params: &spb.SessionParameters{
+			Redundancy:  spb.SessionParameters_SINGLE_PRIMARY,
+			Persistence: spb.SessionParameters_PRESERVE,
+		},
+	})
+
+	err := awaitTimeout(context.Background(), c, t, time.Minute)
+	if err == nil {
+		t.Fatal("did not get expected error from server, got: nil")
+	}
+	t.Logf("Received error from server: %v", err)
+
+	want := fluent.ModifyError().
+		WithCode(codes.FailedPrecondition).
+		AsStatus(t)
+
+	chk.HasRecvClientErrorWithStatus(t, err, want, chk.IgnoreDetails())
+}
+
 // AddIPv4Entry adds a fully referenced IPv4Entry and checks whether the specified ACK
 // type (wantACK) is returned.
 func AddIPv4Entry(c *fluent.GRIBIClient, wantACK fluent.ProgrammingResult, t testing.TB, _ ...TestOpt) {