Check for null pointer in dictRelease, listRelease and cluster_slot_d…

…estroy (#113)

Signed-off-by: Björn Svensson <bjorn.a.svensson@est.tech>

src/adlist.c

@@ -59,6 +59,8 @@ void listRelease(hilist *list) {
     unsigned long len;
     listNode *current, *next;
 
+    if (list == NULL)
+        return;
     current = list->head;
     len = list->len;
     while (len--) {

src/async.c

@@ -156,10 +156,8 @@ static valkeyAsyncContext *valkeyAsyncInitialize(valkeyContext *c) {
 
     return ac;
 oom:
-    if (channels)
-        dictRelease(channels);
-    if (patterns)
-        dictRelease(patterns);
+    dictRelease(channels);
+    dictRelease(patterns);
     return NULL;
 }
 

src/cluster.c

@@ -271,12 +271,8 @@ static void freeValkeyClusterNode(valkeyClusterNode *node) {
         node->acon->data = NULL;
         valkeyAsyncFree(node->acon);
     }
-    if (node->slots != NULL) {
-        listRelease(node->slots);
-    }
-    if (node->slaves != NULL) {
-        listRelease(node->slaves);
-    }
+    listRelease(node->slots);
+    listRelease(node->slaves);
     vk_free(node);
 }
 
@@ -337,6 +333,8 @@ static int cluster_slot_ref_node(cluster_slot *slot, valkeyClusterNode *node) {
 }
 
 static void cluster_slot_destroy(cluster_slot *slot) {
+    if (slot == NULL)
+        return;
     slot->start = 0;
     slot->end = 0;
     slot->node = NULL;
@@ -849,12 +847,8 @@ static dict *parse_cluster_slots(valkeyClusterContext *cc, valkeyReply *reply) {
     // passthrough
 
 error:
-    if (nodes != NULL) {
-        dictRelease(nodes);
-    }
-    if (slot != NULL) {
-        cluster_slot_destroy(slot);
-    }
+    dictRelease(nodes);
+    cluster_slot_destroy(slot);
     return NULL;
 }
 
@@ -1037,9 +1031,7 @@ static dict *parse_cluster_nodes(valkeyClusterContext *cc, valkeyReply *reply) {
         goto error;
     }
 
-    if (nodes_name != NULL) {
-        dictRelease(nodes_name);
-    }
+    dictRelease(nodes_name);
 
     return nodes;
 
@@ -1050,12 +1042,8 @@ static dict *parse_cluster_nodes(valkeyClusterContext *cc, valkeyReply *reply) {
 error:
     sdsfreesplitres(part, count_part);
     sdsfreesplitres(slot_start_end, count_slot_start_end);
-    if (nodes != NULL) {
-        dictRelease(nodes);
-    }
-    if (nodes_name != NULL) {
-        dictRelease(nodes_name);
-    }
+    dictRelease(nodes);
+    dictRelease(nodes_name);
     return NULL;
 }
 
@@ -1233,9 +1221,8 @@ static int updateNodesAndSlotmap(valkeyClusterContext *cc, dict *nodes) {
      * the release procedure might access cc->nodes. */
     dict *oldnodes = cc->nodes;
     cc->nodes = nodes;
-    if (oldnodes != NULL) {
-        dictRelease(oldnodes);
-    }
+    dictRelease(oldnodes);
+
     if (cc->event_callback != NULL) {
         cc->event_callback(cc, VALKEYCLUSTER_EVENT_SLOTMAP_UPDATED,
                            cc->event_privdata);
@@ -1322,14 +1309,8 @@ void valkeyClusterFree(valkeyClusterContext *cc) {
     vk_free(cc->username);
     vk_free(cc->password);
     vk_free(cc->table);
-
-    if (cc->nodes != NULL) {
-        dictRelease(cc->nodes);
-    }
-
-    if (cc->requests != NULL) {
-        listRelease(cc->requests);
-    }
+    dictRelease(cc->nodes);
+    listRelease(cc->requests);
 
     memset(cc, 0xff, sizeof(*cc));
     vk_free(cc);
@@ -2705,10 +2686,8 @@ void valkeyClusterReset(valkeyClusterContext *cc) {
         } while (reply != NULL);
     }
 
-    if (cc->requests) {
-        listRelease(cc->requests);
-        cc->requests = NULL;
-    }
+    listRelease(cc->requests);
+    cc->requests = NULL;
 
     if (cc->need_update_route) {
         status = valkeyClusterUpdateSlotmap(cc);

src/dict.c

@@ -253,6 +253,8 @@ static int _dictClear(dict *ht) {
 
 /* Clear & Release the hash table */
 void dictRelease(dict *ht) {
+    if (ht == NULL)
+        return;
     _dictClear(ht);
     vk_free(ht);
 }