Fix rand_range32() for umax = UINT32_MAX (php#9416)

* Fix rand_range32() for umax = UINT32_MAX

This was introduced in the commit that added the random extension:
4d8dd8d.

Resolves phpGH-9415

* [ci skip] Rename `$r` to `$randomizer` in gh9415.phpt

* Make gh9415.phpt deterministic

* Make gh9415.phpt compatible with 32-bit

Author: TimWolla

NEWS

@@ -10,6 +10,10 @@ PHP                                                                        NEWS
   . Fixed bug GH-9285 (Traits cannot be used in readonly classes).
     (kocsismate)
 
+- Random:
+  . Fixed bug GH-9415 (Randomizer::getInt(0, 2**32 - 1) with Mt19937
+    always returns 1). (timwolla)
+
 - Streams:
   . Fixed bug GH-9316 ($http_response_header is wrong for long status line).
     (cmb, timwolla)

ext/random/random.c

@@ -107,7 +107,7 @@ static inline uint32_t rand_range32(const php_random_algo *algo, php_random_stat
 
 	/* Special case where no modulus is required */
 	if (UNEXPECTED(umax == UINT32_MAX)) {
-		return true;
+		return result;
 	}
 
 	/* Increment the max so range is inclusive of max */

ext/random/tests/03_randomizer/gh9415.phpt

@@ -0,0 +1,19 @@
+--TEST--
+GH-9415: Randomizer::getInt(0, 2**32 - 1) with Mt19937 always returns 1
+--FILE--
+<?php
+
+use Random\Randomizer;
+use Random\Engine\Mt19937;
+
+$randomizer = new Randomizer(new Mt19937(1234));
+// Parameters shifted by -2147483648 to be compatible with 32-bit.
+var_dump($randomizer->getInt(-2147483648, 2147483647));
+
+$randomizer = new Randomizer(new Mt19937(4321));
+var_dump($randomizer->getInt(-2147483648, 2147483647));
+
+?>
+--EXPECT--
+int(-1324913873)
+int(-1843387587)