Fix RESP3 double parsing returning positive INF for -inf (#1716)

parseDouble() returned positive INF for the RESP3 payload ',-inf',
inverting the sign. The value is reachable with protocol=3, for
example ZSCORE on a member whose score is -inf.

The existing infinity test asserted only is_infinite(), which cannot
detect the sign inversion, so it now checks exact values.

NaN payloads keep their current behavior; that is addressed
separately.

CHANGELOG.md

@@ -1,5 +1,11 @@
 ## Changelog
 
+## Unlreleads
+### Added
+### Changed
+### Fixed
+- Fixed RESP3 double parsing returning positive `INF` for `-inf` payloads (#1716)
+
 ## v3.6.0 (2026-08-14)
 ### Added
 - Added support for new TS commands + Indonesian language support integration test (#1695)

VERSION

@@ -1 +1 @@
-3.6.0
+3.6.1-dev

src/Client.php

@@ -56,7 +56,7 @@ use Traversable;
  */
 class Client implements ClientInterface, IteratorAggregate
 {
-    public const VERSION = '3.6.0';
+    public const VERSION = '3.6.1-dev';
 
     /** @var OptionsInterface */
     private $options;

src/Protocol/Parser/Strategy/Resp3Strategy.php

@@ -63,10 +63,14 @@ class Resp3Strategy extends Resp2Strategy
      */
     protected function parseDouble(string $string): float
     {
-        if ($string === 'inf' || $string === '-inf') {
+        if ($string === 'inf') {
             return INF;
         }
 
+        if ($string === '-inf') {
+            return -INF;
+        }
+
         return (float) $string;
     }
 

tests/Predis/Protocol/Parser/Strategy/Resp3StrategyTest.php

@@ -60,11 +60,11 @@ class Resp3StrategyTest extends PredisTestCase
      * @param  string $data
      * @return void
      */
-    public function testParseDataReturnsFloatInfinityOnInfinityOrNegativeInfinity(string $data): void
+    public function testParseDataReturnsFloatInfinityOnInfinityOrNegativeInfinity(string $data, float $expectedValue): void
     {
         $actualResponse = $this->strategy->parseData($data);
 
-        $this->assertInfinite($actualResponse);
+        $this->assertSame($expectedValue, $actualResponse);
     }
 
     /**
@@ -166,8 +166,8 @@ class Resp3StrategyTest extends PredisTestCase
     public function infinityProvider(): array
     {
         return [
-            'positive infinity' => [",inf\r\n"],
-            'negative infinity' => [",-inf\r\n"],
+            'positive infinity' => [",inf\r\n", INF],
+            'negative infinity' => [",-inf\r\n", -INF],
         ];
     }