kvserver: improve a test

This test was performing a configuration change by talking directly to
one of the range's replicas. Instead, this change switches it to use an
Admin request which gets routed to the leaseholder. It's better if the
leaseholder coordinates the configuration change; a non-leaseholder can
error out because it might try to send snapshot before it applied the
preceding descriptor change locally (see cockroachdb#56596). The test seems to
currently work realiably, but, without this patch, becomes flaky with
the next commit which restricts who can take the lease for a range with
no lease.

Release note: None

pkg/kv/kvserver/client_raft_test.go

@@ -1166,6 +1166,7 @@ func TestReplicateAfterRemoveAndSplit(t *testing.T) {
 	defer leaktest.AfterTest(t)()
 	defer log.Scope(t).Close(t)
 
+	ctx := context.Background()
 	sc := kvserver.TestStoreConfig(nil)
 	sc.TestingKnobs.DisableMergeQueue = true
 	sc.TestingKnobs.DisableReplicateQueue = true
@@ -1201,11 +1202,11 @@ func TestReplicateAfterRemoveAndSplit(t *testing.T) {
 	// Split the range.
 	splitKey := roachpb.Key("m")
 	splitArgs := adminSplitArgs(splitKey)
-	if _, err := rep1.AdminSplit(context.Background(), *splitArgs, "test"); err != nil {
+	if _, err := rep1.AdminSplit(ctx, *splitArgs, "test"); err != nil {
 		t.Fatal(err)
 	}
 
-	mtc.advanceClock(context.Background())
+	mtc.advanceClock(ctx)
 
 	// Restart store 2.
 	mtc.restartStore(2)
@@ -1217,20 +1218,16 @@ func TestReplicateAfterRemoveAndSplit(t *testing.T) {
 		startKey := roachpb.RKey(splitKey)
 
 		var desc roachpb.RangeDescriptor
-		if err := mtc.dbs[0].GetProto(context.Background(), keys.RangeDescriptorKey(startKey), &desc); err != nil {
-			t.Fatal(err)
-		}
-
-		rep2, err := mtc.findMemberStoreLocked(desc).GetReplica(desc.RangeID)
-		if err != nil {
+		if err := mtc.dbs[0].GetProto(ctx, keys.RangeDescriptorKey(startKey), &desc); err != nil {
 			t.Fatal(err)
 		}
 
 		chgs := roachpb.MakeReplicationChanges(roachpb.ADD_REPLICA, roachpb.ReplicationTarget{
 			NodeID:  mtc.stores[2].Ident.NodeID,
 			StoreID: mtc.stores[2].Ident.StoreID,
 		})
-		_, err = rep2.ChangeReplicas(context.Background(), &desc, kvserver.SnapshotRequest_REBALANCE, kvserverpb.ReasonRangeUnderReplicated, "", chgs)
+
+		_, err = mtc.dbs[0].AdminChangeReplicas(ctx, startKey, desc, chgs)
 		return err
 	}
 

pkg/kv/kvserver/client_test.go

@@ -1157,24 +1157,6 @@ func (m *multiTestContext) findStartKeyLocked(rangeID roachpb.RangeID) roachpb.R
 	return nil // unreached, but the compiler can't tell.
 }
 
-// findMemberStoreLocked finds a non-stopped Store which is a member
-// of the given range.
-func (m *multiTestContext) findMemberStoreLocked(desc roachpb.RangeDescriptor) *kvserver.Store {
-	for _, s := range m.stores {
-		if s == nil {
-			// Store is stopped.
-			continue
-		}
-		for _, r := range desc.InternalReplicas {
-			if s.StoreID() == r.StoreID {
-				return s
-			}
-		}
-	}
-	m.t.Fatalf("couldn't find a live member of %s", &desc)
-	return nil // unreached, but the compiler can't tell.
-}
-
 // restart stops and restarts all stores but leaves the engines intact,
 // so the stores should contain the same persistent storage as before.
 func (m *multiTestContext) restart() {