From b100c78df95e4443ba1ef8eeaeea21ae49ef9e12 Mon Sep 17 00:00:00 2001
From: huangzhw <huang_zhw@126.com>
Date: Fri, 4 Jun 2021 21:48:51 +0800
Subject: [PATCH 1/4] Fix XTRIM or XADD with LIMIT may delete more entries than
 limit.

---
 src/t_stream.c             |  7 +++----
 tests/unit/type/stream.tcl | 18 ++++++++++++++++++
 2 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/src/t_stream.c b/src/t_stream.c
index 933ab2ff0262..b5da94fc159f 100644
--- a/src/t_stream.c
+++ b/src/t_stream.c
@@ -702,10 +702,6 @@ int64_t streamTrim(stream *s, streamAddTrimArgs *args) {
 
     int64_t deleted = 0;
     while (raxNext(&ri)) {
-        /* Check if we exceeded the amount of work we could do */
-        if (limit && deleted >= limit)
-            break;
-
         if (trim_strategy == TRIM_STRATEGY_MAXLEN && s->length <= maxlen)
             break;
 
@@ -730,6 +726,9 @@ int64_t streamTrim(stream *s, streamAddTrimArgs *args) {
         }
 
         if (remove_node) {
+            /* Check if we exceeded the amount of work we could do */
+            if (limit && (deleted + entries) > limit)
+                break;
             lpFree(lp);
             raxRemove(s->rax,ri.key,ri.key_len,NULL);
             raxSeek(&ri,">=",ri.key,ri.key_len);
diff --git a/tests/unit/type/stream.tcl b/tests/unit/type/stream.tcl
index a89a6529973f..0b19ab5e4d01 100644
--- a/tests/unit/type/stream.tcl
+++ b/tests/unit/type/stream.tcl
@@ -199,6 +199,15 @@ start_server {
         assert {[r EXISTS otherstream] == 0}
     }
 
+    test {XADD with LIMIT delete entries no more than limit} {
+        r del yourstream
+        for {set j 0} {$j < 3} {incr j} {
+            r XADD yourstream * xitem v
+        }
+        r XADD yourstream MAXLEN ~ 0 limit 1 * xitem v
+        assert {[r XLEN yourstream] >= 3}
+    }
+
     test {XRANGE COUNT works as expected} {
         assert {[llength [r xrange mystream - + COUNT 10]] == 10}
     }
@@ -525,6 +534,15 @@ start_server {
         }
         assert_error ERR* {r XTRIM mystream MAXLEN 1 LIMIT 30}
     }
+
+    test {XTRIM with LIMIT delete entries no more than limit} {
+        r del mystream
+        r config set stream-node-max-entries 2
+        for {set j 0} {$j < 3} {incr j} {
+            r XADD mystream * xitem v
+        }
+        assert {[r XTRIM mystream MAXLEN ~ 0 LIMIT 1] <= 1}
+    }
 }
 
 start_server {tags {"stream"} overrides {appendonly yes}} {

From f340b2d2d8de9e564cd04d5e59662421a0e3014d Mon Sep 17 00:00:00 2001
From: huangzhw <huang_zhw@126.com>
Date: Fri, 4 Jun 2021 22:26:40 +0800
Subject: [PATCH 2/4] change order

---
 src/t_stream.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/t_stream.c b/src/t_stream.c
index b5da94fc159f..6bd769ca29c0 100644
--- a/src/t_stream.c
+++ b/src/t_stream.c
@@ -708,6 +708,10 @@ int64_t streamTrim(stream *s, streamAddTrimArgs *args) {
         unsigned char *lp = ri.data, *p = lpFirst(lp);
         int64_t entries = lpGetInteger(p);
 
+        /* Check if we exceeded the amount of work we could do */
+        if (limit && (deleted + entries) > limit)
+            break;
+
         /* Check if we can remove the whole node. */
         int remove_node;
         streamID master_id = {0}; /* For MINID */
@@ -726,9 +730,6 @@ int64_t streamTrim(stream *s, streamAddTrimArgs *args) {
         }
 
         if (remove_node) {
-            /* Check if we exceeded the amount of work we could do */
-            if (limit && (deleted + entries) > limit)
-                break;
             lpFree(lp);
             raxRemove(s->rax,ri.key,ri.key_len,NULL);
             raxSeek(&ri,">=",ri.key,ri.key_len);

From 3a49bf455f3a3a13337dd74b1e89ff6a764bd9e2 Mon Sep 17 00:00:00 2001
From: huangzhw <huang_zhw@126.com>
Date: Fri, 4 Jun 2021 23:17:03 +0800
Subject: [PATCH 3/4] update test

---
 tests/unit/type/stream.tcl | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/unit/type/stream.tcl b/tests/unit/type/stream.tcl
index 0b19ab5e4d01..63a87fe300f2 100644
--- a/tests/unit/type/stream.tcl
+++ b/tests/unit/type/stream.tcl
@@ -205,7 +205,7 @@ start_server {
             r XADD yourstream * xitem v
         }
         r XADD yourstream MAXLEN ~ 0 limit 1 * xitem v
-        assert {[r XLEN yourstream] >= 3}
+        assert {[r XLEN yourstream] == 4}
     }
 
     test {XRANGE COUNT works as expected} {
@@ -541,7 +541,7 @@ start_server {
         for {set j 0} {$j < 3} {incr j} {
             r XADD mystream * xitem v
         }
-        assert {[r XTRIM mystream MAXLEN ~ 0 LIMIT 1] <= 1}
+        assert {[r XTRIM mystream MAXLEN ~ 0 LIMIT 1] == 0}
     }
 }
 

From 95ef9fa475ae14dc11f921011edd3f4431e96915 Mon Sep 17 00:00:00 2001
From: huangzhw <huang_zhw@126.com>
Date: Sat, 5 Jun 2021 06:47:50 +0800
Subject: [PATCH 4/4] add more test

---
 tests/unit/type/stream.tcl | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tests/unit/type/stream.tcl b/tests/unit/type/stream.tcl
index 63a87fe300f2..f1ee56a8a2c9 100644
--- a/tests/unit/type/stream.tcl
+++ b/tests/unit/type/stream.tcl
@@ -542,6 +542,7 @@ start_server {
             r XADD mystream * xitem v
         }
         assert {[r XTRIM mystream MAXLEN ~ 0 LIMIT 1] == 0}
+        assert {[r XTRIM mystream MAXLEN ~ 0 LIMIT 2] == 2}
     }
 }