Fix module / script call CLUSTER SLOTS / SHARDS fake client check crash

src/aof.c

@@ -1371,6 +1371,7 @@ struct client *createAOFClient(void) {
      */
     c->raw_flag = 0;
     c->flag.deny_blocking = 1;
+    c->flag.fake = 1;
 
     /* We set the fake client as a replica waiting for the synchronization
      * so that the server will not try to send replies to this client. */

src/eval.c

@@ -260,6 +260,7 @@ void scriptingInit(int setup) {
     if (lctx.lua_client == NULL) {
         lctx.lua_client = createClient(NULL);
         lctx.lua_client->flag.script = 1;
+        lctx.lua_client->flag.fake = 1;
 
         /* We do not want to allow blocking commands inside Lua */
         lctx.lua_client->flag.deny_blocking = 1;

src/functions.c

@@ -408,6 +408,7 @@ int functionsRegisterEngine(const char *engine_name, engine *engine) {
     client *c = createClient(NULL);
     c->flag.deny_blocking = 1;
     c->flag.script = 1;
+    c->flag.fake = 1;
     engineInfo *ei = zmalloc(sizeof(*ei));
     *ei = (engineInfo){
         .name = engine_name_sds,

src/module.c

@@ -656,6 +656,7 @@ client *moduleAllocTempClient(void) {
     } else {
         c = createClient(NULL);
         c->flag.module = 1;
+        c->flag.fake = 1;
         c->user = NULL; /* Root user */
     }
     return c;
@@ -894,8 +895,10 @@ void moduleCreateContext(ValkeyModuleCtx *out_ctx, ValkeyModule *module, int ctx
     out_ctx->flags = ctx_flags;
     if (ctx_flags & VALKEYMODULE_CTX_TEMP_CLIENT)
         out_ctx->client = moduleAllocTempClient();
-    else if (ctx_flags & VALKEYMODULE_CTX_NEW_CLIENT)
+    else if (ctx_flags & VALKEYMODULE_CTX_NEW_CLIENT) {
         out_ctx->client = createClient(NULL);
+        out_ctx->client->flag.fake = 1;
+    }
 
     /* Calculate the initial yield time for long blocked contexts.
      * in loading we depend on the server hz, but in other cases we also wait

src/networking.c

@@ -346,6 +346,7 @@ client *createCachedResponseClient(int resp) {
     /* Allocating the `conn` allows to prepare the caching client before adding
      * data to the clients output buffer by `prepareClientToWrite`. */
     recording_client->conn = zcalloc(sizeof(connection));
+    recording_client->flag.fake = 1;
     return recording_client;
 }
 
@@ -3246,8 +3247,10 @@ char *getClientSockname(client *c) {
 int isClientConnIpV6(client *c) {
     /* The cached client peer id is on the form "[IPv6]:port" for IPv6
      * addresses, so we just check for '[' here. */
-    if ((c->conn == NULL || c->conn->type == NULL) && server.current_client) {
-        /* Fake client? Use current client instead. */
+    if (c->flag.fake && server.current_client) {
+        /* Fake client? Use current client instead.
+         * Noted that in here we are assuming server.current_client is set
+         * and real (aof has already violated this in loadSingleAppendOnlyFil). */
         c = server.current_client;
     }
     return getClientPeerId(c)[0] == '[';

src/server.h

@@ -1242,7 +1242,8 @@ typedef struct ClientFlags {
     uint64_t dont_cache_primary : 1; /* In some cases we don't want to cache the primary. For example, the replica
                                       * knows that it does not need the cache and required a full sync. With this
                                       * flag, we won't cache the primary in freeClient. */
-    uint64_t reserved : 6;           /* Reserved for future use */
+    uint64_t fake : 1;               /* This is a fake client without a real connection. */
+    uint64_t reserved : 5;           /* Reserved for future use */
 } ClientFlags;
 
 typedef struct client {

tests/integration/aof.tcl

@@ -673,3 +673,26 @@ tags {"aof external:skip"} {
         }
     }
 }
+
+# make sure the test infra won't use SELECT
+set old_singledb $::singledb
+set ::singledb 1
+
+tags {"aof cluster external:skip"} {
+    test {Test cluster slots / cluster shards in aof won't crash} {
+        create_aof $aof_dirpath $aof_file {
+            append_to_aof [formatCommand cluster slots]
+            append_to_aof [formatCommand cluster shards]
+        }
+
+        create_aof_manifest $aof_dirpath $aof_manifest_file {
+            append_to_manifest "file appendonly.aof.1.incr.aof seq 1 type i\n"
+        }
+
+        start_server_aof [list dir $server_path cluster-enabled yes] {
+            assert_equal [r ping] {PONG}
+        }
+    }
+}
+
+set ::singledb $old_singledb