From 75610e3f5536ebe937871d05b4f1cd26088b0476 Mon Sep 17 00:00:00 2001
From: Joseph Doherty <dohejw01@gmail.com>
Date: Thu, 28 May 2026 15:17:10 -0400
Subject: [PATCH] client/go: wrap browseChildren duplicate-page-token error in
 GatewayError

---
 clients/go/mxgateway/galaxy.go      |  5 ++++-
 clients/go/mxgateway/galaxy_test.go | 27 +++++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/clients/go/mxgateway/galaxy.go b/clients/go/mxgateway/galaxy.go
index fa8dc4f..acac8d1 100644
--- a/clients/go/mxgateway/galaxy.go
+++ b/clients/go/mxgateway/galaxy.go
@@ -375,7 +375,10 @@ func (c *GalaxyClient) browseChildrenInner(
 			return nodes, nil
 		}
 		if _, dup := seen[pageToken]; dup {
-			return nil, fmt.Errorf("mxgateway: galaxy browse children returned repeated page token %q", pageToken)
+			return nil, &GatewayError{
+				Op:  "galaxy browse children",
+				Err: fmt.Errorf("repeated page token %q", pageToken),
+			}
 		}
 		seen[pageToken] = struct{}{}
 	}
diff --git a/clients/go/mxgateway/galaxy_test.go b/clients/go/mxgateway/galaxy_test.go
index 5780e5f..0f0202a 100644
--- a/clients/go/mxgateway/galaxy_test.go
+++ b/clients/go/mxgateway/galaxy_test.go
@@ -738,3 +738,30 @@ func TestGalaxyBrowseWithFilterForwardsToRequest(t *testing.T) {
 		t.Fatal("HistorizedOnly = false, want true")
 	}
 }
+
+func TestGalaxyBrowseChildrenRejectsRepeatedPageToken(t *testing.T) {
+	// Build a reply that carries a non-empty NextPageToken so browseChildrenInner
+	// will request a second page. Queue the same reply twice so the second response
+	// returns the same page token, triggering the duplicate-token guard.
+	page := buildBrowseReply(
+		[]*pb.GalaxyObject{obj(1, "Plant", true)},
+		[]bool{true},
+		1,
+	)
+	page.NextPageToken = "1:abc:1"
+
+	fake := &fakeGalaxyServer{
+		browseChildrenReplies: []*pb.BrowseChildrenReply{page, page},
+	}
+	client, cleanup := newGalaxyBufconnClient(t, fake)
+	defer cleanup()
+
+	_, err := client.Browse(context.Background(), nil)
+	if err == nil {
+		t.Fatal("Browse: error = nil, want repeated-page-token error")
+	}
+	var gwErr *GatewayError
+	if !errors.As(err, &gwErr) {
+		t.Fatalf("error type = %T, want *GatewayError; err = %v", err, err)
+	}
+}