Fix #80763: msgfmt_format() does not accept DateTime references

`intl_zval_to_millis()` needs to cater to references.

Closes GH-6707.

NEWS

@@ -2,6 +2,10 @@ PHP                                                                        NEWS
 |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 ?? ??? 2021, php 7.4.17
 
+- Intl:
+  . Fixed bug #80763 (msgfmt_format() does not accept DateTime references).
+    (cmb)
+
 - MySQLnd:
   . Fixed bug #80713 (SegFault when disabling ATTR_EMULATE_PREPARES and
     MySQL 8.0). (Nikita)

ext/intl/common/common_date.cpp

@@ -175,6 +175,7 @@ U_CFUNC double intl_zval_to_millis(zval *z, intl_error *err, const char *func)
 		return ZEND_NAN;
 	}
 
+try_again:
 	switch (Z_TYPE_P(z)) {
 	case IS_STRING:
 		type = is_numeric_string(Z_STRVAL_P(z), Z_STRLEN_P(z), &lv, &rv, 0);
@@ -227,6 +228,9 @@ U_CFUNC double intl_zval_to_millis(zval *z, intl_error *err, const char *func)
 			efree(message);
 		}
 		break;
+	case IS_REFERENCE:
+		z = Z_REFVAL_P(z);
+		goto try_again;
 	default:
 		spprintf(&message, 0, "%s: invalid PHP type for date", func);
 		intl_errors_set(err, U_ILLEGAL_ARGUMENT_ERROR,

ext/intl/tests/bug80763.phpt

@@ -0,0 +1,16 @@
+--TEST--
+Bug #80763 (msgfmt_format() does not accept DateTime references)
+--SKIPIF--
+<?php
+if (!extension_loaded('intl')) die('skip intl extension not available');
+?>
+--FILE--
+<?php
+$today = new DateTime('2021-02-17 12:00:00');
+$formatter = new \MessageFormatter('en_US', 'Today is {today, date, full}.');
+$params = ['today' => $today];
+array_walk($params, fn() => 1);
+var_dump($formatter->format($params));
+?>
+--EXPECT--
+string(38) "Today is Wednesday, February 17, 2021."