Fixed bug #73730 (textdomain(null) throws in strict mode)

The $text_domain parameter may be NULL, which we have to cater to
explicitly with regard to strict_types.

NEWS

@@ -21,6 +21,9 @@ PHP                                                                        NEWS
   . Fixed bug #75124 (gdImageGrayScale() may produce colors). (cmb)
   . Fixed bug #75139 (libgd/gd_interpolation.c:1786: suspicious if ?). (cmb)
 
+- Gettext:
+  . Fixed bug #73730 (textdomain(null) throws in strict mode). (cmb)
+
 - Intl:
   . Fixed bug #75090 (IntlGregorianCalendar doesn't have constants from parent
     class). (tpunt)

ext/gettext/gettext.c

@@ -161,16 +161,16 @@ PHP_MINFO_FUNCTION(php_gettext)
    Set the textdomain to "domain". Returns the current domain */
 PHP_NAMED_FUNCTION(zif_textdomain)
 {
-	char *domain, *domain_name, *retval;
-	size_t domain_len;
+	char *domain = NULL, *domain_name, *retval;
+	size_t domain_len = 0;
 
-	if (zend_parse_parameters(ZEND_NUM_ARGS(), "s", &domain, &domain_len) == FAILURE) {
+	if (zend_parse_parameters(ZEND_NUM_ARGS(), "s!", &domain, &domain_len) == FAILURE) {
 		return;
 	}
 
 	PHP_GETTEXT_DOMAIN_LENGTH_CHECK
 
-	if (strcmp(domain, "") && strcmp(domain, "0")) {
+	if (domain != NULL && strcmp(domain, "") && strcmp(domain, "0")) {
 		domain_name = domain;
 	} else {
 		domain_name = NULL;

ext/gettext/tests/bug73730.phpt

@@ -0,0 +1,16 @@
+--TEST--
+Bug #73730 (textdomain(null) throws in strict mode)
+--SKIPIF--
+<?php
+if (!extension_loaded('gettext')) die('skip gettext extension is not available');
+?>
+--FILE--
+<?php
+declare(strict_types=1);
+
+var_dump(textdomain(null));
+?>
+===DONE===
+--EXPECT--
+string(8) "messages"
+===DONE===