Add warning for negative steps

Author: Girgias

ext/standard/array.c

@@ -2751,6 +2751,10 @@ PHP_FUNCTION(range)
 
 			/* We only want positive step values. */
 			if (step_double < 0.0) {
+				php_error_docref(NULL, E_WARNING, "Argument #3 ($step) must be greater than 0, $step multiplied by -1");
+				if (UNEXPECTED(EG(exception))) {
+					RETURN_THROWS();
+				}
 				step_double *= -1;
 			}
 			step = zend_dval_to_lval(step_double);
@@ -2761,6 +2765,10 @@ PHP_FUNCTION(range)
 			step = Z_LVAL_P(user_step);
 			/* We only want positive step values. */
 			if (step < 0) {
+				php_error_docref(NULL, E_WARNING, "Argument #3 ($step) must be greater than 0, $step multiplied by -1");
+				if (UNEXPECTED(EG(exception))) {
+					RETURN_THROWS();
+				}
 				step *= -1;
 			}
 			step_double = (double) step;

ext/standard/tests/array/range/range_step_errors.phpt

@@ -87,8 +87,30 @@ try {
     echo $e->getMessage(), "\n";
 }
 
+echo "Step must not be negative\n";
+try {
+    var_dump(range('a', 'c', -1));
+} catch (\ValueError $e) {
+    echo $e->getMessage(), "\n";
+}
+try {
+    var_dump(range(1, 3, -1));
+} catch (\ValueError $e) {
+    echo $e->getMessage(), "\n";
+}
+try {
+    var_dump(range('a', 'c', -1));
+} catch (\ValueError $e) {
+    echo $e->getMessage(), "\n";
+}
+try {
+    var_dump(range(1.5, 3.5, -1.5));
+} catch (\ValueError $e) {
+    echo $e->getMessage(), "\n";
+}
+
 ?>
---EXPECT--
+--EXPECTF--
 Step cannot be 0
 range(): Argument #3 ($step) cannot be 0
 range(): Argument #3 ($step) cannot be 0
@@ -111,3 +133,42 @@ range(): Argument #3 ($step) must be less than the range spanned by argument #1
 range(): Argument #3 ($step) must be less than the range spanned by argument #1 ($start) and argument #2 ($end)
 -- Testing ( (low > high) && (low-high < step) ) for characters --
 range(): Argument #3 ($step) must be less than the range spanned by argument #1 ($start) and argument #2 ($end)
+Step must not be negative
+
+Warning: range(): Argument #3 ($step) must be greater than 0, $step multiplied by -1 in %s on line %d
+array(3) {
+  [0]=>
+  string(1) "a"
+  [1]=>
+  string(1) "b"
+  [2]=>
+  string(1) "c"
+}
+
+Warning: range(): Argument #3 ($step) must be greater than 0, $step multiplied by -1 in %s on line %d
+array(3) {
+  [0]=>
+  int(1)
+  [1]=>
+  int(2)
+  [2]=>
+  int(3)
+}
+
+Warning: range(): Argument #3 ($step) must be greater than 0, $step multiplied by -1 in %s on line %d
+array(3) {
+  [0]=>
+  string(1) "a"
+  [1]=>
+  string(1) "b"
+  [2]=>
+  string(1) "c"
+}
+
+Warning: range(): Argument #3 ($step) must be greater than 0, $step multiplied by -1 in %s on line %d
+array(2) {
+  [0]=>
+  float(1.5)
+  [1]=>
+  float(3)
+}