Modules: Replicate lazy-expire even if replication is not allowed (#8816)

Before this commit using RM_Call without "!" could cause the master
to lazy-expire a key (delete it) but without replicating to replicas.
This could cause the replica's memory usage to gradually grow and
could also cause consistency issues if the master and replica have
a clock diff.
This bug was introduced in #8617

Added a test which demonstrates that scenario.

3 files changed, 49 insertions, 1 deletions

diff --git a/src/db.c b/src/db.c
index 27af0a53e..ec68c228c 100644
--- a/src/db.c
+++ b/src/db.c
@@ -1453,7 +1453,12 @@ void propagateExpire(redisDb *db, robj *key, int lazy) {
     incrRefCount(argv[0]);
     incrRefCount(argv[1]);
 
+    /* If the master decided to expire a key we must propagate it to replicas no matter what..
+     * Even if module executed a command without asking for propagation. */
+    int prev_replication_allowed = server.replication_allowed;
+    server.replication_allowed = 1;
     propagate(server.delCommand,db->id,argv,2,PROPAGATE_AOF|PROPAGATE_REPL);
+    server.replication_allowed = prev_replication_allowed;
 
     decrRefCount(argv[0]);
     decrRefCount(argv[1]);
diff --git a/tests/modules/propagate.c b/tests/modules/propagate.c
index 7a63ed807..ac04d4f9d 100644
--- a/tests/modules/propagate.c
+++ b/tests/modules/propagate.c
@@ -192,6 +192,19 @@ int propagateTestNestedCommand(RedisModuleCtx *ctx, RedisModuleString **argv, in
     return REDISMODULE_OK;
 }
 
+int propagateTestIncr(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
+{
+    REDISMODULE_NOT_USED(argc);
+    RedisModuleCallReply *reply;
+
+    /* This test propagates the module command, not the INCR it executes. */
+    reply = RedisModule_Call(ctx, "INCR", "s", argv[1]);
+    RedisModule_ReplyWithCallReply(ctx,reply);
+    RedisModule_FreeCallReply(reply);
+    RedisModule_ReplicateVerbatim(ctx);
+    return REDISMODULE_OK;
+}
+
 int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
     REDISMODULE_NOT_USED(argv);
     REDISMODULE_NOT_USED(argc);
@@ -234,5 +247,10 @@ int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
                 "",1,1,1) == REDISMODULE_ERR)
             return REDISMODULE_ERR;
 
+    if (RedisModule_CreateCommand(ctx,"propagate-test.incr",
+                propagateTestIncr,
+                "",1,1,1) == REDISMODULE_ERR)
+            return REDISMODULE_ERR;
+
     return REDISMODULE_OK;
 }
diff --git a/tests/unit/moduleapi/propagate.tcl b/tests/unit/moduleapi/propagate.tcl
index 108637dd9..a8c710074 100644
--- a/tests/unit/moduleapi/propagate.tcl
+++ b/tests/unit/moduleapi/propagate.tcl
@@ -2,7 +2,7 @@ set testmodule [file normalize tests/modules/propagate.so]
 
 tags "modules" {
     test {Modules can propagate in async and threaded contexts} {
-        start_server {} {
+        start_server [list overrides [list loadmodule "$testmodule"]] {
             set replica [srv 0 client]
             set replica_host [srv 0 host]
             set replica_port [srv 0 port]
@@ -213,6 +213,31 @@ tags "modules" {
                     }
                     close_replication_stream $repl
                 }
+
+                test {module RM_Call of expired key propagation} {
+                    $master debug set-active-expire 0
+
+                    $master set k1 900 px 100
+                    wait_for_ofs_sync $master $replica
+                    after 110
+
+                    set repl [attach_to_replication_stream]
+                    $master propagate-test.incr k1
+                    wait_for_ofs_sync $master $replica
+
+                    assert_replication_stream $repl {
+                        {select *}
+                        {del k1}
+                        {propagate-test.incr k1}
+                    }
+                    close_replication_stream $repl
+
+                    assert_equal [$master get k1] 1
+                    assert_equal [$master ttl k1] -1
+                    assert_equal [$replica get k1] 1
+                    assert_equal [$replica ttl k1] -1
+                }
+
                 assert_equal [s -1 unexpected_error_replies] 0
             }
         }