Fixed the behavior when construct/unserialize is executed multiple times.

Author: SakiTakamachi

ext/bcmath/bcmath.c

@@ -1355,14 +1355,19 @@ PHP_METHOD(BcMath_Number, __construct)
 		Z_PARAM_STR_OR_LONG(str, lval);
 	ZEND_PARSE_PARAMETERS_END();
 
+	bcmath_number_obj_t *intern = get_bcmath_number_from_zval(ZEND_THIS);
+	if (UNEXPECTED(intern->num != NULL)) {
+		zend_readonly_property_modification_error_ex(ZSTR_VAL(bcmath_number_ce->name), "value");
+		RETURN_THROWS();
+	}
+
 	bc_num num = NULL;
 	size_t scale;
 	if (bc_num_from_obj_or_str_or_long_with_err(&num, &scale, NULL, str, lval, 1) == FAILURE) {
 		bc_free_num(&num);
 		RETURN_THROWS();
 	}
 
-	bcmath_number_obj_t *intern = get_bcmath_number_from_zval(ZEND_THIS);
 	intern->num = num;
 	intern->scale = scale;
 }
@@ -1737,15 +1742,19 @@ PHP_METHOD(BcMath_Number, __unserialize)
 		goto fail;
 	}
 
+	bcmath_number_obj_t *intern = get_bcmath_number_from_zval(ZEND_THIS);
+	if (UNEXPECTED(intern->num != NULL)) {
+		zend_readonly_property_modification_error_ex(ZSTR_VAL(bcmath_number_ce->name), "value");
+		RETURN_THROWS();
+	}
+
 	bc_num num = NULL;
 	size_t scale;
 	if (php_str2num_ex(&num, Z_STR_P(zv), &scale) == FAILURE) {
 		bc_free_num(&num);
 		goto fail;
 	}
 
-	bcmath_number_obj_t *intern = get_bcmath_number_from_zval(ZEND_THIS);
-
 	intern->num = num;
 	intern->scale = scale;
 

ext/bcmath/tests/number/construct_error.phpt

@@ -4,6 +4,13 @@ BcMath\Number construct error
 bcmath
 --FILE--
 <?php
+try {
+    $num = new BcMath\Number('1');
+    $num->__construct(5);
+} catch (Error $e) {
+    echo $e->getMessage() . "\n";
+}
+
 try {
     $num = new BcMath\Number('a');
     var_dump($num);
@@ -12,4 +19,5 @@ try {
 }
 ?>
 --EXPECT--
+Cannot modify readonly property BcMath\Number::$value
 BcMath\Number::__construct(): Argument #1 ($num) is not well-formed

ext/bcmath/tests/number/unserialize_error.phpt

@@ -4,11 +4,19 @@ BcMath\Number unserialize error
 bcmath
 --FILE--
 <?php
+try {
+    $num = new BcMath\Number(1);
+    $num->__unserialize(['value' => '5']);
+} catch (Error $e) {
+    echo $e->getMessage() . "\n";
+}
+
 try {
     unserialize('O:13:"BcMath\Number":1:{s:5:"value";s:1:"a";}');
 } catch (Exception $e) {
     echo $e->getMessage();
 }
 ?>
 --EXPECT--
+Cannot modify readonly property BcMath\Number::$value
 Invalid serialization data for BcMath\Number object