From f3fcf9a06e38bdef6cd37f46c358716446fde31b Mon Sep 17 00:00:00 2001
From: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Date: Wed, 21 Oct 2026 14:29:49 -0700
Subject: [PATCH] ec distribution: register each node id once

Adding the same node twice appended it to RackToNodes twice, so every
count that walks rack nodes double-counted its shards.
---
 weed/storage/erasure_coding/distribution/analysis.go |  5 ++++-
 .../erasure_coding/distribution/distribution_test.go | 12 ++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/weed/storage/erasure_coding/distribution/analysis.go b/weed/storage/erasure_coding/distribution/analysis.go
index 2a7c98b820..5f60efda56 100644
--- a/weed/storage/erasure_coding/distribution/analysis.go
+++ b/weed/storage/erasure_coding/distribution/analysis.go
@@ -16,8 +16,11 @@ func NewTopologyAnalysis() *TopologyAnalysis {
 }
 
 // AddNode registers a node in the topology, including any shards it already
-// holds for the volume being analyzed.
+// holds for the volume being analyzed. A node id may only register once.
 func (a *TopologyAnalysis) AddNode(node *TopologyNode) {
+	if _, ok := a.AllNodes[node.NodeID]; ok {
+		return
+	}
 	a.AllNodes[node.NodeID] = node
 	a.RackToNodes[rackKey(node.DataCenter, node.Rack)] = append(a.RackToNodes[rackKey(node.DataCenter, node.Rack)], node)
 	if !contains(a.DCToRacks[node.DataCenter], node.Rack) {
diff --git a/weed/storage/erasure_coding/distribution/distribution_test.go b/weed/storage/erasure_coding/distribution/distribution_test.go
index 574bab7b06..367807ac10 100644
--- a/weed/storage/erasure_coding/distribution/distribution_test.go
+++ b/weed/storage/erasure_coding/distribution/distribution_test.go
@@ -125,6 +125,18 @@ func TestTopologyAnalysis(t *testing.T) {
 	assert.Equal(t, []int{0, 1, 2}, a.RackToShards[rackKey("dc1", "r1")])
 }
 
+// A node registered twice must still count once in rack and shard totals.
+func TestTopologyAnalysisDuplicateNode(t *testing.T) {
+	a := NewTopologyAnalysis()
+	a.AddNode(makeNode("n1", "dc1", "r1", 5, 0, 1))
+	a.AddNode(makeNode("n1", "dc1", "r1", 5, 0, 1))
+	a.Finalize()
+
+	assert.Equal(t, 1, a.TotalNodes)
+	assert.Len(t, a.RackToNodes[rackKey("dc1", "r1")], 1)
+	assert.Equal(t, 2, a.ShardsByNode["n1"])
+}
+
 // Shards may be registered either through TopologyNode.ShardIDs or through
 // AddShardLocation — both must leave the node holding the shards.
 func TestTopologyAnalysisAddShardLocation(t *testing.T) {