From c55e33a99fa2efd5a9583964c45425ef0855182b Mon Sep 17 00:00:00 2001
From: Moti Cohen <moticless@gmail.com>
Date: Thu, 31 Jul 2025 15:44:25 +0300
Subject: [PATCH] KEYSIZES - Fix resolving key slot on modules (#14240)

In cluster mode with modules, for a given key, the slot resolution for
the KEYSIZES histogram update was incorrect. As a result, the histogram
might gracefully ignored those keys instead or update the wrong slot
histogram.
---
 src/module.c                  |  6 +++---
 tests/unit/moduleapi/list.tcl | 31 +++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/src/module.c b/src/module.c
index 41e6d93d3..216030809 100644
--- a/src/module.c
+++ b/src/module.c
@@ -4743,7 +4743,7 @@ int RM_ListDelete(RedisModuleKey *key, long index) {
     if (moduleListIteratorSeek(key, index, REDISMODULE_WRITE)) {
         listTypeDelete(key->iter, &key->u.list.entry);
         int64_t l = (int64_t) listTypeLength(key->kv);
-        updateKeysizesHist(key->db, getKeySlot(key->kv->ptr), OBJ_LIST, l+1, l);
+        updateKeysizesHist(key->db, getKeySlot(key->key->ptr), OBJ_LIST, l+1, l);
         if (moduleDelKeyIfEmpty(key)) return REDISMODULE_OK;
         listTypeTryConversion(key->kv, LIST_CONV_SHRINKING, moduleFreeListIterator, key);
         if (!key->iter) return REDISMODULE_OK; /* Return ASAP if iterator has been freed */
@@ -4872,7 +4872,7 @@ int RM_ZsetIncrby(RedisModuleKey *key, double score, RedisModuleString *ele, int
     }
     if (out_flags & ZADD_OUT_ADDED) {
         int64_t l = (int64_t) zsetLength(key->kv);
-        updateKeysizesHist(key->db, getKeySlot(key->kv->ptr), OBJ_ZSET, l-1, l);
+        updateKeysizesHist(key->db, getKeySlot(key->key->ptr), OBJ_ZSET, l-1, l);
     }
     if (flagsptr) *flagsptr = moduleZsetAddFlagsFromCoreFlags(out_flags);
     return REDISMODULE_OK;
@@ -4902,7 +4902,7 @@ int RM_ZsetRem(RedisModuleKey *key, RedisModuleString *ele, int *deleted) {
     if (key->kv != NULL && zsetDel(key->kv,ele->ptr)) {
         if (deleted) *deleted = 1;
         int64_t l = (int64_t) zsetLength(key->kv);
-        updateKeysizesHist(key->db, getKeySlot(key->kv->ptr), OBJ_ZSET, l+1, l);
+        updateKeysizesHist(key->db, getKeySlot(key->key->ptr), OBJ_ZSET, l+1, l);
         moduleDelKeyIfEmpty(key);
     } else {
         if (deleted) *deleted = 0;
diff --git a/tests/unit/moduleapi/list.tcl b/tests/unit/moduleapi/list.tcl
index 53f79ca4a..91793c54f 100644
--- a/tests/unit/moduleapi/list.tcl
+++ b/tests/unit/moduleapi/list.tcl
@@ -192,3 +192,34 @@ start_server {tags {"modules"}} {
         assert_equal {OK} [r module unload list]
     }
 }
+
+# A basic test that exercises a module's list commands under cluster mode.
+# Currently, many module commands are never run even once in a clustered setup.
+# This test helps ensure that basic module functionality works correctly and that
+# the KEYSIZES histogram remains accurate and that insert & delete was tested.
+set testmodule [file normalize tests/modules/list.so]
+set modules [list loadmodule $testmodule]
+start_cluster 2 2 [list config_lines [list loadmodule $testmodule enable-debug-command yes]] {
+    test "Module list - KEYSIZES is updated correctly in cluster mode" {
+        for {set srvid -2} {$srvid <= 0} {incr srvid} {
+            set instance [srv $srvid client]
+            # Assert consistency after each command
+            $instance DEBUG KEYSIZES-HIST-ASSERT 1
+    
+            for {set i 0} {$i < 50} {incr i} {
+                for {set j 0} {$j < 4} {incr j} {
+                    catch {$instance list.insert "list:$i" $j "item:$j"} e
+                    if {![string match "OK" $e]} {assert_match "*MOVED*" $e}
+                }
+            }
+            for {set i 0} {$i < 50} {incr i} {
+                for {set j 0} {$j < 4} {incr j} {
+                    catch {$instance list.delete "list:$i" 0} e
+                    if {![string match "OK" $e]} {assert_match "*MOVED*" $e}
+                }
+            }
+            # Verify also that instance is responsive and didn't crash on assert
+            assert_equal [$instance dbsize] 0
+        }
+    }
+}