Un-register notification and server event when RedisModule_OnLoad fails

When we register notification or server event in RedisModule_OnLoad, but
RedisModule_OnLoad eventually fails, triggering notification or server event
will cause the server to crash.

If the loading fails on a later stage of moduleLoad, we do call moduleUnload
which handles all un-registration, but when it fails on the RedisModule_OnLoad
call, we only un-register several specific things and these two are missing.

Fixes redis#12808.

src/module.c

@@ -12190,6 +12190,8 @@ int moduleLoad(const char *path, void **module_argv, int module_argc, int is_loa
             moduleRemoveCateogires(ctx.module);
             moduleRemoveConfigs(ctx.module);
             moduleUnregisterAuthCBs(ctx.module);
+            moduleUnsubscribeNotifications(ctx.module);
+            moduleUnsubscribeAllServerEvents(ctx.module);
             moduleFreeModuleStructure(ctx.module);
         }
         moduleFreeContext(&ctx);

tests/modules/hooks.c

@@ -407,9 +407,6 @@ int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
         return REDISMODULE_ERR; \
     }
 
-    REDISMODULE_NOT_USED(argv);
-    REDISMODULE_NOT_USED(argc);
-
     if (RedisModule_Init(ctx,"testhook",1,REDISMODULE_APIVER_1)
         == REDISMODULE_ERR) return REDISMODULE_ERR;
 
@@ -471,6 +468,18 @@ int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
     if (RedisModule_CreateCommand(ctx,"hooks.pexpireat", cmdKeyExpiry,"",0,0,0) == REDISMODULE_ERR)
         return REDISMODULE_ERR;
 
+    if (argc == 1) {
+        const char *ptr = RedisModule_StringPtrLen(argv[0], NULL);
+        if (!strcasecmp(ptr, "noload")) {
+            /* This is a hint that we return ERR at the last moment of OnLoad. */
+            RedisModule_FreeDict(ctx, event_log);
+            RedisModule_FreeDict(ctx, removed_event_log);
+            RedisModule_FreeDict(ctx, removed_subevent_type);
+            RedisModule_FreeDict(ctx, removed_expiry_log);
+            return REDISMODULE_ERR;
+        }
+    }
+
     return REDISMODULE_OK;
 }
 

tests/modules/keyspace_events.c

@@ -318,9 +318,6 @@ static int cmdGetDels(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
 /* This function must be present on each Redis module. It is used in order to
  * register the commands into the Redis server. */
 int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
-    REDISMODULE_NOT_USED(argv);
-    REDISMODULE_NOT_USED(argc);
-
     if (RedisModule_Init(ctx,"testkeyspace",1,REDISMODULE_APIVER_1) == REDISMODULE_ERR){
         return REDISMODULE_ERR;
     }
@@ -405,6 +402,16 @@ int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
         return REDISMODULE_ERR;
     }
 
+    if (argc == 1) {
+        const char *ptr = RedisModule_StringPtrLen(argv[0], NULL);
+        if (!strcasecmp(ptr, "noload")) {
+            /* This is a hint that we return ERR at the last moment of OnLoad. */
+            RedisModule_FreeDict(ctx, loaded_event_log);
+            RedisModule_FreeDict(ctx, module_event_log);
+            return REDISMODULE_ERR;
+        }
+    }
+
     return REDISMODULE_OK;
 }
 

tests/unit/moduleapi/hooks.tcl

@@ -310,4 +310,12 @@ tags "modules" {
             assert_equal [string match {*module-event-shutdown*} [exec tail -5 < $replica_stdout]] 1
         }
     }
+
+    start_server {} {
+        test {OnLoad failure will handle un-registration} {
+            catch {r module load $testmodule noload}
+            r flushall
+            r ping
+        }
+    }
 }

tests/unit/moduleapi/keyspace_events.tcl

@@ -102,4 +102,17 @@ tags "modules" {
             assert_equal {OK} [r set x 1 EX 1]
         }
     }
+
+    start_server {} {
+        test {OnLoad failure will handle un-registration} {
+            catch {r module load $testmodule noload}
+            r set x 1
+            r hset y f v
+            r lpush z 1 2 3
+            r sadd p 1 2 3
+            r zadd t 1 f1 2 f2
+            r xadd s * f v
+            r ping
+        }
+    }
 }