Fix crash on RM_Call inside module load (#11346)

PR #9320 introduces initialization order changes. Now cluster is initialized after modules.
This changes causes a crash if the module uses RM_Call inside the load function
on cluster mode (the code will try to access `server.cluster` which at this point is NULL).

To solve it, separate cluster initialization into 2 phases:
1. Structure initialization that happened before the modules initialization
2. Listener initialization that happened after.

Test was added to verify the fix.

1 files changed, 22 insertions, 0 deletions

diff --git a/tests/modules/basics.c b/tests/modules/basics.c
index 55b36fa5e..b6f9766c6 100644
--- a/tests/modules/basics.c
+++ b/tests/modules/basics.c
@@ -893,6 +893,28 @@ int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
     if (RedisModule_Init(ctx,"test",1,REDISMODULE_APIVER_1)
         == REDISMODULE_ERR) return REDISMODULE_ERR;
 
+    /* Perform RM_Call inside the RedisModule_OnLoad
+     * to verify that it works as expected without crashing.
+     * The tests will verify it on different configurations
+     * options (cluster/no cluster). A simple ping command
+     * is enough for this test. */
+    RedisModuleCallReply *reply = RedisModule_Call(ctx, "ping", "");
+    if (RedisModule_CallReplyType(reply) != REDISMODULE_REPLY_STRING) {
+        RedisModule_FreeCallReply(reply);
+        return REDISMODULE_ERR;
+    }
+    size_t len;
+    const char *reply_str = RedisModule_CallReplyStringPtr(reply, &len);
+    if (len != 4) {
+        RedisModule_FreeCallReply(reply);
+        return REDISMODULE_ERR;
+    }
+    if (memcmp(reply_str, "PONG", 4) != 0) {
+        RedisModule_FreeCallReply(reply);
+        return REDISMODULE_ERR;
+    }
+    RedisModule_FreeCallReply(reply);
+
     if (RedisModule_CreateCommand(ctx,"test.call",
         TestCall,"write deny-oom",1,1,1) == REDISMODULE_ERR)
         return REDISMODULE_ERR;