From 454e12cb8961f21c9dd8502dc82ae6ffd7e22fe0 Mon Sep 17 00:00:00 2001
From: Oran Agra <oran@redislabs.com>
Date: Wed, 4 Dec 2019 17:29:29 +0200
Subject: [PATCH] AOFRW on an empty stream created with MKSTREAM loads badkly

the AOF will be loaded successfully, but the stream will be missing,
i.e inconsistencies with the original db.

this was because XADD with id of 0-0 would error.

add a test to reproduce.
---
 src/aof.c                          |  3 ++-
 tests/unit/type/stream-cgroups.tcl | 13 +++++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/aof.c b/src/aof.c
index 8ab9349f0..6bb239252 100644
--- a/src/aof.c
+++ b/src/aof.c
@@ -1212,12 +1212,13 @@ int rewriteStreamObject(rio *r, robj *key, robj *o) {
         /* Use the XADD MAXLEN 0 trick to generate an empty stream if
          * the key we are serializing is an empty string, which is possible
          * for the Stream type. */
+        id.ms = 0; id.seq = 1; 
         if (rioWriteBulkCount(r,'*',7) == 0) return 0;
         if (rioWriteBulkString(r,"XADD",4) == 0) return 0;
         if (rioWriteBulkObject(r,key) == 0) return 0;
         if (rioWriteBulkString(r,"MAXLEN",6) == 0) return 0;
         if (rioWriteBulkString(r,"0",1) == 0) return 0;
-        if (rioWriteBulkStreamID(r,&s->last_id) == 0) return 0;
+        if (rioWriteBulkStreamID(r,&id) == 0) return 0;
         if (rioWriteBulkString(r,"x",1) == 0) return 0;
         if (rioWriteBulkString(r,"y",1) == 0) return 0;
     }
diff --git a/tests/unit/type/stream-cgroups.tcl b/tests/unit/type/stream-cgroups.tcl
index 072ed14d6..6b9a4a9cd 100644
--- a/tests/unit/type/stream-cgroups.tcl
+++ b/tests/unit/type/stream-cgroups.tcl
@@ -311,4 +311,17 @@ start_server {
             }
         }
     }
+
+    start_server {tags {"stream"} overrides {appendonly yes aof-use-rdb-preamble no}} {
+        test {Empty stream with no lastid can be rewrite into AOF correctly} {
+            r XGROUP CREATE mystream group-name $ MKSTREAM
+            assert {[dict get [r xinfo stream mystream] length] == 0}
+            set grpinfo [r xinfo groups mystream]
+            r bgrewriteaof
+            waitForBgrewriteaof r
+            r debug loadaof
+            assert {[dict get [r xinfo stream mystream] length] == 0}
+            assert {[r xinfo groups mystream] == $grpinfo}
+        }
+    }
 }