Add get_error_handler(), get_exception_handler() functions

RFC: https://wiki.php.net/rfc/get-error-exception-handler

Closes GH-17693

Author: arnaud-lb

NEWS

@@ -40,6 +40,7 @@ PHP                                                                        NEWS
   . Fixed bug GH-18026 (Improve "expecting token" error for ampersand). (ilutov)
   . Added the (void) cast to indicate that not using a value is intentional.
     (timwolla)
+  . Added get_error_handler(), get_exception_handler() functions. (Arnaud)
 
 - Curl:
   . Added curl_multi_get_handles(). (timwolla)

UPGRADING

@@ -244,6 +244,12 @@ PHP 8.5 UPGRADE NOTES
 6. New Functions
 ========================================
 
+- Core:
+  . get_error_handler() allows retrieving the current user-defined error handler
+    function
+  . get_exception_handler() allows retrieving the current user-defined exception
+    handler function
+
 - Curl:
   . curl_multi_get_handles() allows retrieving all CurlHandles current
     attached to a CurlMultiHandle. This includes both handles added using

Zend/tests/get_error_handler.phpt

@@ -0,0 +1,88 @@
+--TEST--
+get_error_handler()
+--FILE--
+<?php
+
+class C {
+    function handle() {}
+    static function handleStatic() {}
+}
+
+class Invokable {
+    public function __invoke() {
+    }
+}
+
+function foo() {}
+
+echo "No error handler\n";
+var_dump(get_error_handler() === null);
+
+echo "\nFunction string\n";
+set_error_handler('foo');
+var_dump(get_error_handler() === 'foo');
+
+echo "\nNULL\n";
+set_error_handler(null);
+var_dump(get_error_handler() === null);
+
+echo "\nStatic method array\n";
+set_error_handler([C::class, 'handleStatic']);
+var_dump(get_error_handler() === [C::class, 'handleStatic']);
+
+echo "\nStatic method string\n";
+set_error_handler('C::handleStatic');
+var_dump(get_error_handler() === 'C::handleStatic');
+
+echo "\nInstance method array\n";
+set_error_handler([$c = new C(), 'handle']);
+var_dump(get_error_handler() === [$c, 'handle']);
+
+echo "\nFirst class callable method\n";
+set_error_handler($f = (new C())->handle(...));
+var_dump(get_error_handler() === $f);
+
+echo "\nClosure\n";
+set_error_handler($f = function () {});
+var_dump(get_error_handler() === $f);
+
+echo "\nInvokable\n";
+set_error_handler($object = new Invokable());
+var_dump(get_error_handler() === $object);
+
+echo "\nStable return value\n";
+var_dump(get_error_handler() === get_error_handler());
+
+?>
+==DONE==
+--EXPECT--
+No error handler
+bool(true)
+
+Function string
+bool(true)
+
+NULL
+bool(true)
+
+Static method array
+bool(true)
+
+Static method string
+bool(true)
+
+Instance method array
+bool(true)
+
+First class callable method
+bool(true)
+
+Closure
+bool(true)
+
+Invokable
+bool(true)
+
+Stable return value
+bool(true)
+==DONE==

Zend/tests/get_exception_handler.phpt

@@ -0,0 +1,87 @@
+--TEST--
+get_exception_handler()
+--FILE--
+<?php
+
+class C {
+    function handle() {}
+    static function handleStatic() {}
+}
+
+class Invokable {
+    public function __invoke() {
+    }
+}
+
+function foo() {}
+
+echo "No exception handler\n";
+var_dump(get_exception_handler() === null);
+
+echo "\nFunction string\n";
+set_exception_handler('foo');
+var_dump(get_exception_handler() === 'foo');
+
+echo "\nNULL\n";
+set_exception_handler(null);
+var_dump(get_exception_handler() === null);
+
+echo "\nStatic method array\n";
+set_exception_handler([C::class, 'handleStatic']);
+var_dump(get_exception_handler() === [C::class, 'handleStatic']);
+
+echo "\nStatic method string\n";
+set_exception_handler('C::handleStatic');
+var_dump(get_exception_handler() === 'C::handleStatic');
+
+echo "\nInstance method array\n";
+set_exception_handler([$c = new C(), 'handle']);
+var_dump(get_exception_handler() === [$c, 'handle']);
+
+echo "\nFirst class callable method\n";
+set_exception_handler($f = (new C())->handle(...));
+var_dump(get_exception_handler() === $f);
+
+echo "\nClosure\n";
+set_exception_handler($f = function () {});
+var_dump(get_exception_handler() === $f);
+
+echo "\nInvokable\n";
+set_exception_handler($object = new Invokable());
+var_dump(get_exception_handler() === $object);
+
+echo "\nStable return value\n";
+var_dump(get_exception_handler() === get_exception_handler());
+
+?>==DONE==
+--EXPECT--
+No exception handler
+bool(true)
+
+Function string
+bool(true)
+
+NULL
+bool(true)
+
+Static method array
+bool(true)
+
+Static method string
+bool(true)
+
+Instance method array
+bool(true)
+
+First class callable method
+bool(true)
+
+Closure
+bool(true)
+
+Invokable
+bool(true)
+
+Stable return value
+bool(true)
+==DONE==

Zend/zend_builtin_functions.c

@@ -1322,6 +1322,15 @@ ZEND_FUNCTION(restore_error_handler)
 }
 /* }}} */
 
+ZEND_FUNCTION(get_error_handler)
+{
+	ZEND_PARSE_PARAMETERS_NONE();
+
+	if (Z_TYPE(EG(user_error_handler)) != IS_UNDEF) {
+		RETURN_COPY(&EG(user_error_handler));
+	}
+}
+
 /* {{{ Sets a user-defined exception handler function. Returns the previously defined exception handler, or false on error */
 ZEND_FUNCTION(set_exception_handler)
 {
@@ -1368,6 +1377,15 @@ ZEND_FUNCTION(restore_exception_handler)
 }
 /* }}} */
 
+ZEND_FUNCTION(get_exception_handler)
+{
+	ZEND_PARSE_PARAMETERS_NONE();
+
+	if (Z_TYPE(EG(user_exception_handler)) != IS_UNDEF) {
+		RETURN_COPY(&EG(user_exception_handler));
+	}
+}
+
 static inline void get_declared_class_impl(INTERNAL_FUNCTION_PARAMETERS, int flags) /* {{{ */
 {
 	zend_string *key;

Zend/zend_builtin_functions.stub.php

@@ -117,11 +117,15 @@ function set_error_handler(?callable $callback, int $error_levels = E_ALL) {}
 
 function restore_error_handler(): true {}
 
+function get_error_handler(): ?callable {}
+
 /** @return callable|null */
 function set_exception_handler(?callable $callback) {}
 
 function restore_exception_handler(): true {}
 
+function get_exception_handler(): ?callable {}
+
 /**
  * @return array<int, string>
  * @refcount 1