From e106644572377841c9c4cba624280cfa595a41c3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Bolina?= <jbolina@redhat.com>
Date: Tue, 20 Aug 2024 17:55:41 -0300
Subject: [PATCH] fix: Lcs response parse

* Handle parsing `len` and `matches` in any order;
---
 .../core/output/StringMatchResultOutput.java  | 20 ++++++---
 .../StringMatchResultOutputUnitTests.java     | 43 +++++++++++++++++++
 2 files changed, 58 insertions(+), 5 deletions(-)
 create mode 100644 src/test/java/io/lettuce/core/output/StringMatchResultOutputUnitTests.java

diff --git a/src/main/java/io/lettuce/core/output/StringMatchResultOutput.java b/src/main/java/io/lettuce/core/output/StringMatchResultOutput.java
index 2653f8f2cc..d062966a7b 100644
--- a/src/main/java/io/lettuce/core/output/StringMatchResultOutput.java
+++ b/src/main/java/io/lettuce/core/output/StringMatchResultOutput.java
@@ -23,6 +23,7 @@
 import static io.lettuce.core.StringMatchResult.Position;
 
 import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -37,6 +38,8 @@
  */
 public class StringMatchResultOutput<K, V> extends CommandOutput<K, V, StringMatchResult> {
 
+    private static final ByteBuffer LEN = StandardCharsets.US_ASCII.encode("len");
+
     private final boolean withIdx;
 
     private String matchString;
@@ -45,6 +48,8 @@ public class StringMatchResultOutput<K, V> extends CommandOutput<K, V, StringMat
 
     private List<Long> positions;
 
+    private boolean readingLen = true;
+
     private final List<MatchedPosition> matchedPositions = new ArrayList<>();
 
     public StringMatchResultOutput(RedisCodec<K, V> codec, boolean withIdx) {
@@ -57,18 +62,23 @@ public void set(ByteBuffer bytes) {
 
         if (!withIdx && matchString == null) {
             matchString = (String) codec.decodeKey(bytes);
+        } else {
+            readingLen = LEN.equals(bytes);
         }
     }
 
     @Override
     public void set(long integer) {
 
-        this.len = (int) integer;
-
-        if (positions == null) {
-            positions = new ArrayList<>();
+        if (readingLen) {
+            this.len = (int) integer;
+        } else {
+            if (positions == null) {
+                positions = new ArrayList<>();
+            }
+            positions.add(integer);
         }
-        positions.add(integer);
+
     }
 
     @Override
diff --git a/src/test/java/io/lettuce/core/output/StringMatchResultOutputUnitTests.java b/src/test/java/io/lettuce/core/output/StringMatchResultOutputUnitTests.java
new file mode 100644
index 0000000000..a10a400c65
--- /dev/null
+++ b/src/test/java/io/lettuce/core/output/StringMatchResultOutputUnitTests.java
@@ -0,0 +1,43 @@
+package io.lettuce.core.output;
+
+import io.lettuce.core.StringMatchResult;
+import io.lettuce.core.codec.StringCodec;
+import org.junit.jupiter.api.Test;
+
+import java.nio.ByteBuffer;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class StringMatchResultOutputUnitTests {
+
+    @Test
+    void parseLenAndMatches() {
+        StringMatchResultOutput<String, String> output = new StringMatchResultOutput<>(new StringCodec(), false);
+
+        output.set(ByteBuffer.wrap("len".getBytes()));
+        output.set(42);
+
+        output.set(ByteBuffer.wrap("matches".getBytes()));
+        output.set(0);
+        output.set(5);
+        output.set(10);
+        output.set(15);
+
+        output.complete(2);
+        output.complete(0);
+
+        StringMatchResult result = output.get();
+
+        assertThat(result.getLen()).isEqualTo(42);
+
+        assertThat(result.getMatches()).hasSize(1).satisfies(m -> assertMatchedPositions(m.get(0), 0, 5, 10, 15));
+    }
+
+    private void assertMatchedPositions(StringMatchResult.MatchedPosition match, int... expected) {
+        assertThat(match.getA().getStart()).isEqualTo(expected[0]);
+        assertThat(match.getA().getEnd()).isEqualTo(expected[1]);
+        assertThat(match.getB().getStart()).isEqualTo(expected[2]);
+        assertThat(match.getB().getEnd()).isEqualTo(expected[3]);
+    }
+
+}