RFC: Counting of non-countable objects

UPGRADING

@@ -108,6 +108,8 @@ PHP 7.2 UPGRADE NOTES
       'Multiple' => ['One header', 'Another header'],
       'Multiline' = "FirstLine\r\n SecondLine",
     ];
+  . count() now raises a warning when an invalid parameter is passed.
+    Only arrays and objects implementing the Countable interface should be passed.
 
 - XML:
   . utf8_encode() and utf8_decode() have been moved to the Standard extension

Zend/tests/generators/errors/count_error.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Generators can't be counted
+--FILE--
+<?php
+
+function gen() { yield; }
+
+$gen = gen();
+
+try {
+    count($gen);
+} catch (Exception $e) {
+    echo $e;
+}
+
+?>
+--EXPECTF--
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d

ext/date/tests/timezone_transitions_get_variation2.phpt

@@ -145,24 +145,32 @@ int(8)
 
 Warning: timezone_transitions_get() expects parameter 2 to be integer, array given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- int indexed array --
 
 Warning: timezone_transitions_get() expects parameter 2 to be integer, array given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- associative array --
 
 Warning: timezone_transitions_get() expects parameter 2 to be integer, array given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- nested arrays --
 
 Warning: timezone_transitions_get() expects parameter 2 to be integer, array given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- uppercase NULL --
@@ -193,48 +201,64 @@ int(8)
 
 Warning: timezone_transitions_get() expects parameter 2 to be integer, string given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- empty string SQ --
 
 Warning: timezone_transitions_get() expects parameter 2 to be integer, string given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- string DQ --
 
 Warning: timezone_transitions_get() expects parameter 2 to be integer, string given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- string SQ --
 
 Warning: timezone_transitions_get() expects parameter 2 to be integer, string given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- mixed case string --
 
 Warning: timezone_transitions_get() expects parameter 2 to be integer, string given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- heredoc --
 
 Warning: timezone_transitions_get() expects parameter 2 to be integer, string given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- instance of classWithToString --
 
 Warning: timezone_transitions_get() expects parameter 2 to be integer, object given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- instance of classWithoutToString --
 
 Warning: timezone_transitions_get() expects parameter 2 to be integer, object given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- undefined var --
@@ -249,5 +273,7 @@ int(8)
 
 Warning: timezone_transitions_get() expects parameter 2 to be integer, resource given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 ===DONE===

ext/date/tests/timezone_transitions_get_variation3.phpt

@@ -145,24 +145,32 @@ int(1)
 
 Warning: timezone_transitions_get() expects parameter 3 to be integer, array given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- int indexed array --
 
 Warning: timezone_transitions_get() expects parameter 3 to be integer, array given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- associative array --
 
 Warning: timezone_transitions_get() expects parameter 3 to be integer, array given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- nested arrays --
 
 Warning: timezone_transitions_get() expects parameter 3 to be integer, array given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- uppercase NULL --
@@ -193,48 +201,64 @@ int(1)
 
 Warning: timezone_transitions_get() expects parameter 3 to be integer, string given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- empty string SQ --
 
 Warning: timezone_transitions_get() expects parameter 3 to be integer, string given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- string DQ --
 
 Warning: timezone_transitions_get() expects parameter 3 to be integer, string given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- string SQ --
 
 Warning: timezone_transitions_get() expects parameter 3 to be integer, string given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- mixed case string --
 
 Warning: timezone_transitions_get() expects parameter 3 to be integer, string given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- heredoc --
 
 Warning: timezone_transitions_get() expects parameter 3 to be integer, string given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- instance of classWithToString --
 
 Warning: timezone_transitions_get() expects parameter 3 to be integer, object given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- instance of classWithoutToString --
 
 Warning: timezone_transitions_get() expects parameter 3 to be integer, object given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 
 -- undefined var --
@@ -249,5 +273,7 @@ int(1)
 
 Warning: timezone_transitions_get() expects parameter 3 to be integer, resource given in %s on line %d
 string(7) "boolean"
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 int(1)
 ===DONE===

ext/standard/array.c

@@ -790,6 +790,7 @@ PHP_FUNCTION(count)
 
 	switch (Z_TYPE_P(array)) {
 		case IS_NULL:
+			php_error_docref(NULL, E_WARNING, "Parameter must be an array or an object that implements Countable");
 			RETURN_LONG(0);
 			break;
 		case IS_ARRAY:
@@ -820,8 +821,14 @@ PHP_FUNCTION(count)
 				}
 				return;
 			}
+
+			/* If There's no handler and it doesn't implement Countable then add a warning */
+			php_error_docref(NULL, E_WARNING, "Parameter must be an array or an object that implements Countable");
+			RETURN_LONG(1);
+			break;
 		}
 		default:
+			php_error_docref(NULL, E_WARNING, "Parameter must be an array or an object that implements Countable");
 			RETURN_LONG(1);
 			break;
 	}

ext/standard/tests/array/count_invalid.phpt

@@ -0,0 +1,42 @@
+--TEST--
+Only arrays and countable objects can be counted
+--FILE--
+<?php
+
+$result = count(null);
+var_dump($result);
+
+$result = count("string");
+var_dump($result);
+
+$result = count(123);
+var_dump($result);
+
+$result = count(true);
+var_dump($result);
+
+$result = count(false);
+var_dump($result);
+
+$result = count((object) []);
+var_dump($result);
+
+?>
+--EXPECTF--
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
+int(0)
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
+int(1)
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
+int(1)
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
+int(1)
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
+int(1)
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
+int(1)

ext/standard/tests/array/count_recursive.phpt

@@ -132,7 +132,11 @@ closedir( $resource2 );
 --EXPECTF--
 *** Testing basic functionality of count() function ***
 -- Testing NULL --
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 COUNT_NORMAL: should be 0, is 0
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 COUNT_RECURSIVE: should be 0, is 0
 -- Testing arrays --
 COUNT_NORMAL: should be 2, is 2
@@ -141,9 +145,15 @@ COUNT_RECURSIVE: should be 8, is 8
 COUNT_NORMAL: should be 3, is 3
 COUNT_RECURSIVE: should be 6, is 6
 -- Testing strings --
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 COUNT_NORMAL: should be 1, is 1
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 COUNT_RECURSIVE: should be 1, is 1
 -- Testing various types with no second argument --
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 COUNT_NORMAL: should be 1, is 1
 COUNT_NORMAL: should be 2, is 2
 -- Testing really cool arrays --
@@ -184,11 +194,19 @@ COUNT_NORMAL is 4
 COUNT_RECURSIVE is 7
 
 -- Testing count() on constants with no second argument --
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 COUNT_NORMAL: should be 1, is 1
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 COUNT_NORMAL: should be 1, is 1
 
 -- Testing count() on NULL and Unset variables --
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 COUNT_NORMAL: should be 0, is 0
+
+Warning: count(): Parameter must be an array or an object that implements Countable in %s on line %d
 COUNT_NORMAL: should be 1, is 1
 COUNT_NORMAL: should be 0, is 0