Promote warning to ValueError for Spoofchecker::setRestrictionLevel()

Closes GH-6197

Author: Girgias

ext/intl/spoofchecker/spoofchecker_main.c

@@ -125,6 +125,7 @@ PHP_METHOD(Spoofchecker, setChecks)
 /* }}} */
 
 #if U_ICU_VERSION_MAJOR_NUM >= 58
+/* TODO Document this method on PHP.net */
 /* {{{ Set the loosest restriction level allowed for strings. */
 PHP_METHOD(Spoofchecker, setRestrictionLevel)
 {
@@ -143,8 +144,10 @@ PHP_METHOD(Spoofchecker, setRestrictionLevel)
 			USPOOF_MODERATELY_RESTRICTIVE != level &&
 			USPOOF_MINIMALLY_RESTRICTIVE != level &&
 			USPOOF_UNRESTRICTIVE != level) {
-		php_error_docref(NULL, E_WARNING, "Invalid restriction level value");
-		return;
+		zend_argument_value_error(1, "must be one of Spoofchecker::ASCII, Spoofchecker::SINGLE_SCRIPT_RESTRICTIVE, "
+			"Spoofchecker::SINGLE_HIGHLY_RESTRICTIVE, Spoofchecker::SINGLE_MODERATELY_RESTRICTIVE, "
+			"Spoofchecker::SINGLE_MINIMALLY_RESTRICTIVE, or Spoofchecker::UNRESTRICTIVE");
+		RETURN_THROWS();
 	}
 
 	uspoof_setRestrictionLevel(co->uspoof, (URestrictionLevel)level);

ext/intl/tests/spoofchecker_unknown_restriction_level.phpt

@@ -0,0 +1,17 @@
+--TEST--
+Spoofchecker attempting to pass an unknown restriction level
+--SKIPIF--
+<?php if(!extension_loaded('intl') || !class_exists("Spoofchecker")) print 'skip'; ?>
+--FILE--
+<?php
+
+$x = new Spoofchecker();
+try {
+    $x->setRestrictionLevel(Spoofchecker::SINGLE_SCRIPT);
+} catch (\ValueError $e) {
+    echo $e->getMessage(), \PHP_EOL;
+}
+
+?>
+--EXPECT--
+Spoofchecker::setRestrictionLevel(): Argument #1 ($level) must be one of Spoofchecker::ASCII, Spoofchecker::SINGLE_SCRIPT_RESTRICTIVE, Spoofchecker::SINGLE_HIGHLY_RESTRICTIVE, Spoofchecker::SINGLE_MODERATELY_RESTRICTIVE, Spoofchecker::SINGLE_MINIMALLY_RESTRICTIVE, or Spoofchecker::UNRESTRICTIVE