Throw ValueError when 1 is provided to the second argument of log()

Author: alexandre-daubois

UPGRADING

@@ -142,6 +142,8 @@ PHP 8.5 UPGRADE NOTES
   . Using a printf-family function with a formatter that did not specify the
     precision previously incorrectly reset the precision instead of treating
     it as a precision of 0. See GH-18897.
+  . Passing 1 as the second argument to log() now throws a ValueError.
+    Previously, it returned NaN.
 
 ========================================
 2. New Features

ext/standard/math.c

@@ -668,7 +668,8 @@ PHP_FUNCTION(log)
 	}
 
 	if (base == 1.0) {
-		RETURN_DOUBLE(ZEND_NAN);
+        zend_argument_value_error(2, "must not be 1");
+        RETURN_THROWS();
 	}
 
 	if (base <= 0.0) {

ext/standard/tests/math/log_error.phpt

@@ -9,6 +9,13 @@ try {
 } catch (ValueError $exception) {
     echo $exception->getMessage() . "\n";
 }
+
+try {
+    log(36, 1);
+} catch (ValueError $exception) {
+    echo $exception->getMessage() . "\n";
+}
 ?>
 --EXPECT--
 log(): Argument #2 ($base) must be greater than 0
+log(): Argument #2 ($base) must not be 1