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--- rfc:get_class_disallow_null_parameter [2016/08/13 22:55] – created danack
+++ rfc:get_class_disallow_null_parameter [2018/03/01 23:26] (current) – RFC was implemented in PHP 7.2 carusogabriel
@@ Line 1: / Line 1: @@
 ====== PHP RFC: get_class() disallow null parameter ======
-  * Version: 0.9
+  * Version: 1.0
   * Date: 2016-08-12
   * Author: Danack
-  * Status: Draft
+  * Status: Implemented (in PHP 7.2)
   * First Published at: https://wiki.php.net/rfc/get_class_disallow_null_parameter
@@ Line 26: / Line 26: @@
 If $result contains null, the output will be of the class context where get_class() was called from, in this case "Foo".
+This feature violates the [[https://en.wikipedia.org/wiki/Principle_of_least_astonishment|Principle of least astonishment]]: "if a necessary feature has a high astonishment factor, it may be necessary to redesign the feature."
 ===== Proposal =====
-Disallow null being passed to the function as a valid parameter.
+Disallow null being passed to the function as a valid parameter. If get_class() is called with null as the parameter, a warning will be emitted:
+<code>
+Warning: get_class() expects parameter 1 to be object, null given in %s on line %d
+</code>
 I.e. the valid ways to call the function will be:
-* called without any parameter.
+  * without any parameter.
-* called with an object as the parameter.
+  * with an object as the parameter.
 Those two options will continue to have the same behaviour they currently have.
@@ Line 53: / Line 61: @@
 <code php>
 if ($some_value_that_may_be_null === null) {
-    $x = null;
+    $x = get_class();
 }
 else {
@@ Line 63: / Line 71: @@
 .2
-===== Proposed Voting Choices =====
+===== Voting =====
-The voting question will be "Should the function be changed to disallow null being passed as a parameter?" with yes/no being the options. As it is not a language or syntax change, the vote will pass if 50%+1 vote yes.
+Should the get_class() function be changed to disallow null being passed as a parameter? As it is not a language or syntax change, the vote will pass if 50%+1 vote yes.
-===== Patches and Tests =====
+<doodle title="get_class() disallow null parameter" auth="Danack" voteType="single" closed="true">
+   * Yes
+   * No
+</doodle>
-https://github.com/Danack/php-src/tree/get_class_rfc
+Voting ended on the 8th October 2016 9pm UTC
-===== Implementation =====
+===== null vs default param =====
-After the project is implemented, this section should contain
-  - the version(s) it was merged to
-  - a link to the git commit(s)
-  - a link to the PHP manual entry for the feature
+When this topic was discussed before, it came as a surprise to some people that PHP can tell the difference between passing null and having a default value be null. This is perfectly possible in both internal code, as well as userland code:
+<code php>
+function get_class($item = null)
+{
+    if (func_num_args() == 0) {
+        return get_current_scope_name();
+    }
+    if ($item === null) {
+        trigger_error("get_class passed null, which is not an object.");
+    }
+    if (is_object($item) == false) {
+        trigger_error("value is not an object");
+        return false;
+    }
+    return gettype($item);
+}
+</code>
+===== Patches and Tests =====
+https://github.com/php/php-src/pull/2082
+===== Implementation =====
+After the project is implemented, this section should contain
+  - This was merged for PHP 7.2
+  - https://github.com/php/php-src/pull/2082/commits/86aa1c784d3b584e6d0c235870a882c8fd169a74
+  - https://secure.php.net/manual/en/function.get-class.php#refsect1-function.get-class-changelog

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