From f2a8041cd5690d3416c1705b25f3b9b4635d1b55 Mon Sep 17 00:00:00 2001
From: Valentino Geron <valentino@redislabs.com>
Date: Thu, 1 Apr 2021 12:13:55 +0300
Subject: [PATCH] Fix XAUTOCLAIM response to return the next available id as
 the cursor (#8725)

This command used to return the last scanned entry id as the cursor,
instead of the next one to be scanned.
so in the next call, the user could / should have sent `(cursor` and not
just `cursor` if he wanted to avoid scanning the same record twice.

Scanning the record twice would look odd if someone is checking what
exactly was scanned, but it also has a side effect of incrementing the
delivery count twice.
---
 src/t_stream.c                     |  3 +++
 tests/unit/type/stream-cgroups.tcl | 12 ++++++------
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/t_stream.c b/src/t_stream.c
index 1407ee98b..f175eed9a 100644
--- a/src/t_stream.c
+++ b/src/t_stream.c
@@ -3151,6 +3151,9 @@ void xautoclaimCommand(client *c) {
         server.dirty++;
     }
 
+    /* We need to return the next entry as a cursor for the next XAUTOCLAIM call */
+    raxNext(&ri);
+
     streamID endid;
     if (raxEOF(&ri)) {
         endid.ms = endid.seq = 0;
diff --git a/tests/unit/type/stream-cgroups.tcl b/tests/unit/type/stream-cgroups.tcl
index f8de0741d..53eb46ca3 100644
--- a/tests/unit/type/stream-cgroups.tcl
+++ b/tests/unit/type/stream-cgroups.tcl
@@ -373,7 +373,7 @@ start_server {
         after 200
         set reply [r XAUTOCLAIM mystream mygroup consumer2 10 - COUNT 1]
         assert_equal [llength $reply] 2
-        assert_equal [lindex $reply 0] $id1
+        assert_equal [lindex $reply 0] "0-0"
         assert_equal [llength [lindex $reply 1]] 1
         assert_equal [llength [lindex $reply 1 0]] 2
         assert_equal [llength [lindex $reply 1 0 1]] 2
@@ -392,7 +392,7 @@ start_server {
         set reply [r XAUTOCLAIM mystream mygroup consumer2 10 - COUNT 2]
         # id1 is self-claimed here but not id2 ('count' was set to 2)
         assert_equal [llength $reply] 2
-        assert_equal [lindex $reply 0] $id2
+        assert_equal [lindex $reply 0] $id3
         assert_equal [llength [lindex $reply 1]] 2
         assert_equal [llength [lindex $reply 1 0]] 2
         assert_equal [llength [lindex $reply 1 0 1]] 2
@@ -438,22 +438,22 @@ start_server {
         set reply [r XAUTOCLAIM mystream mygroup consumer2 10 - COUNT 2]
         assert_equal [llength $reply] 2
         set cursor [lindex $reply 0]
-        assert_equal $cursor $id2
+        assert_equal $cursor $id3
         assert_equal [llength [lindex $reply 1]] 2
         assert_equal [llength [lindex $reply 1 0 1]] 2
         assert_equal [lindex $reply 1 0 1] {a 1}
 
         # Claim 2 more entries
-        set reply [r XAUTOCLAIM mystream mygroup consumer2 10 ($cursor COUNT 2]
+        set reply [r XAUTOCLAIM mystream mygroup consumer2 10 $cursor COUNT 2]
         assert_equal [llength $reply] 2
         set cursor [lindex $reply 0]
-        assert_equal $cursor $id4
+        assert_equal $cursor $id5
         assert_equal [llength [lindex $reply 1]] 2
         assert_equal [llength [lindex $reply 1 0 1]] 2
         assert_equal [lindex $reply 1 0 1] {c 3}
 
         # Claim last entry
-        set reply [r XAUTOCLAIM mystream mygroup consumer2 10 ($cursor COUNT 2]
+        set reply [r XAUTOCLAIM mystream mygroup consumer2 10 $cursor COUNT 1]
         assert_equal [llength $reply] 2
         set cursor [lindex $reply 0]
         assert_equal $cursor {0-0}