From 140923722fbac014f1f7a98ab6fba2bd37b93130 Mon Sep 17 00:00:00 2001
From: Andrey Zvonov <32552679+zvonand@users.noreply.github.com>
Date: Wed, 28 Jan 2026 11:04:01 +0100
Subject: [PATCH] Merge pull request #1343 from
 Altinity/backports/25.8.15/90243

25.8.15 Stable backport of #90243: Fix crash in StorageDistributed when parsing malformed shard directory names
---
 src/Storages/StorageDistributed.cpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/Storages/StorageDistributed.cpp b/src/Storages/StorageDistributed.cpp
index e9336640334f..52f9c0dcf4ee 100644
--- a/src/Storages/StorageDistributed.cpp
+++ b/src/Storages/StorageDistributed.cpp
@@ -2015,9 +2015,11 @@ Cluster::Addresses StorageDistributed::parseAddresses(const std::string & name)
                 continue;
             }
 
-            if (address.replica_index > replicas)
+            if (address.replica_index == 0 || address.replica_index > replicas)
             {
-                LOG_ERROR(log, "No shard with replica_index={} ({})", address.replica_index, name);
+                LOG_ERROR(log, "Invalid replica_index={} for directory '{}' (cluster has {} replicas for shard {}). "
+                               "Expected directory format: 'shardN_replicaM' or 'shardN_all_replicas'",
+                                address.replica_index, dirname, replicas, address.shard_index);
                 continue;
             }