bug #60908 [Uid] Improve entropy of the increment for UUIDv7 (nicolas-grekas)

nicolas-grekas · nicolas-grekas · commit 95c85091e87d · 2025-06-27T17:10:11.000+02:00
This PR was merged into the 6.4 branch. Discussion ---------- [Uid] Improve entropy of the increment for UUIDv7 | Q | A | ------------- | --- | Branch? | 6.4 | Bug fix? | yes | New feature? | no | Deprecations? | no | Issues | - | License | MIT Looks like we're missing the sign bit when computing the random increments on x64. Commits ------- 125f4ad [Uid] Improve entropy of the increment for UUIDv7
diff --git a/src/Symfony/Component/Uid/UuidV7.php b/src/Symfony/Component/Uid/UuidV7.php
@@ -60,7 +60,7 @@ public static function generate(?\DateTimeInterface $time = null): string
 
         if ($time > self::$time || (null !== $mtime && $time !== self::$time)) {
             randomize:
-            self::$rand = unpack('n*', isset(self::$seed) ? random_bytes(10) : self::$seed = random_bytes(16));
+            self::$rand = unpack('S*', isset(self::$seed) ? random_bytes(10) : self::$seed = random_bytes(16));
             self::$rand[1] &= 0x03FF;
             self::$time = $time;
         } else {
@@ -76,7 +76,7 @@ public static function generate(?\DateTimeInterface $time = null): string
             // 24-bit number in the self::$seedParts list and decrement self::$seedIndex.
 
             if (!self::$seedIndex) {
-                $s = unpack('l*', self::$seed = hash('sha512', self::$seed, true));
+                $s = unpack(\PHP_INT_SIZE >= 8 ? 'L*' : 'l*', self::$seed = hash('sha512', self::$seed, true));
                 $s[] = ($s[1] >> 8 & 0xFF0000) | ($s[2] >> 16 & 0xFF00) | ($s[3] >> 24 & 0xFF);
                 $s[] = ($s[4] >> 8 & 0xFF0000) | ($s[5] >> 16 & 0xFF00) | ($s[6] >> 24 & 0xFF);
                 $s[] = ($s[7] >> 8 & 0xFF0000) | ($s[8] >> 16 & 0xFF00) | ($s[9] >> 24 & 0xFF);
