From: Andrea Faulds <ajf@ajf.me>
Date: Wed, 14 Oct 2015 18:15:32 +0000 (+0100)
Subject: Add void return type
X-Git-Tag: php-7.1.0alpha1~714
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=366ba41334870f325f248d8e486e3ebf8bafb984;p=php

Add void return type
---

diff --git a/NEWS b/NEWS
index 1d9fd2a100..c33379064b 100644
--- a/NEWS
+++ b/NEWS
@@ -4,6 +4,7 @@ PHP                                                                        NEWS
 
 Core:
   . Fixed bug #62210 (Exceptions can leak temporary variables). (Dmitry, Bob)
+  . Added void return type. (Andrea)
 
 Standard
   . Implemented FR #55716 (Add an option to pass a custom stream context to
diff --git a/UPGRADING b/UPGRADING
index 44516e9079..8929404d98 100644
--- a/UPGRADING
+++ b/UPGRADING
@@ -18,10 +18,16 @@ PHP 7.1 UPGRADE NOTES
 ========================================
 1. Backward Incompatible Changes
 ========================================
+- Core:
+  . 'void' can no longer be used as the name of a class, interface, or trait.
+    This applies to declarations, class_alias() and use statements.
 
 ========================================
 2. New Features
 ========================================
+- Core
+  . Added void return type, which requires that a function not return a value.
+    (RFC: https://wiki.php.net/rfc/void_return_type)
 
 ========================================
 3. Changes in SAPI modules
diff --git a/Zend/tests/return_types/void_allowed.phpt b/Zend/tests/return_types/void_allowed.phpt
new file mode 100644
index 0000000000..8f07c7392e
--- /dev/null
+++ b/Zend/tests/return_types/void_allowed.phpt
@@ -0,0 +1,20 @@
+--TEST--
+void return type: acceptable cases
+--FILE--
+<?php
+
+function foo(): void {
+    // okay
+}
+
+foo();
+
+function bar(): void {
+    return; // okay
+}
+
+bar();
+
+echo "OK!", PHP_EOL;
+--EXPECT--
+OK!
diff --git a/Zend/tests/return_types/void_disallowed1.phpt b/Zend/tests/return_types/void_disallowed1.phpt
new file mode 100644
index 0000000000..b20f129a58
--- /dev/null
+++ b/Zend/tests/return_types/void_disallowed1.phpt
@@ -0,0 +1,12 @@
+--TEST--
+void return type: unacceptable cases: explicit NULL return
+--FILE--
+<?php
+
+function foo(): void {
+    return NULL; // not permitted in a void function
+}
+
+// Note the lack of function call: function validated at compile-time
+--EXPECTF--
+Fatal error: A void function must not return a value in %s on line %d
diff --git a/Zend/tests/return_types/void_disallowed2.phpt b/Zend/tests/return_types/void_disallowed2.phpt
new file mode 100644
index 0000000000..7bbc3ac24f
--- /dev/null
+++ b/Zend/tests/return_types/void_disallowed2.phpt
@@ -0,0 +1,12 @@
+--TEST--
+void return type: unacceptable cases: explicit return of some other value
+--FILE--
+<?php
+
+function foo(): void {
+    return -1; // not permitted in a void function
+}
+
+// Note the lack of function call: function validated at compile-time
+--EXPECTF--
+Fatal error: A void function must not return a value in %s on line %d
diff --git a/Zend/tests/return_types/void_parameter.phpt b/Zend/tests/return_types/void_parameter.phpt
new file mode 100644
index 0000000000..4c6e918406
--- /dev/null
+++ b/Zend/tests/return_types/void_parameter.phpt
@@ -0,0 +1,8 @@
+--TEST--
+void return type: not valid as a parameter type
+--FILE--
+<?php
+
+function foobar(void $a) {}
+--EXPECTF--
+Fatal error: void cannot be used as a parameter type in %s on line %d
diff --git a/Zend/zend_API.c b/Zend/zend_API.c
index 5a488f7e9d..384599b90e 100644
--- a/Zend/zend_API.c
+++ b/Zend/zend_API.c
@@ -183,6 +183,8 @@ ZEND_API char *zend_get_type_by_const(int type) /* {{{ */
 			return "callable";
 		case IS_ARRAY:
 			return "array";
+		case IS_VOID:
+			return "void";
 		default:
 			return "unknown";
 	}
diff --git a/Zend/zend_compile.c b/Zend/zend_compile.c
index a987dcef83..092c7af466 100644
--- a/Zend/zend_compile.c
+++ b/Zend/zend_compile.c
@@ -153,6 +153,7 @@ static const struct reserved_class_name reserved_class_names[] = {
 	{ZEND_STRL("static")},
 	{ZEND_STRL("string")},
 	{ZEND_STRL("true")},
+	{ZEND_STRL("void")},
 	{NULL, 0}
 };
 
@@ -196,6 +197,7 @@ static const builtin_type_info builtin_types[] = {
 	{ZEND_STRL("float"), IS_DOUBLE},
 	{ZEND_STRL("string"), IS_STRING},
 	{ZEND_STRL("bool"), _IS_BOOL},
+	{ZEND_STRL("void"), IS_VOID},
 	{NULL, 0, IS_UNDEF}
 };
 
@@ -2164,6 +2166,11 @@ static zend_op *zend_delayed_compile_end(uint32_t offset) /* {{{ */
 
 static void zend_emit_return_type_check(znode *expr, zend_arg_info *return_info) /* {{{ */
 {
+	/* `return ...;` is illegal in a void function (but `return;` isn't) */
+	if (expr && return_info->type_hint == IS_VOID) {
+		zend_error_noreturn(E_COMPILE_ERROR, "A void function must not return a value");
+	}
+
 	if (return_info->type_hint != IS_UNDEF) {
 		zend_op *opline = zend_emit_op(NULL, ZEND_VERIFY_RETURN_TYPE, expr, NULL);
 		if (expr && expr->op_type == IS_CONST) {
@@ -4706,6 +4713,10 @@ void zend_compile_params(zend_ast *ast, zend_ast *return_type_ast) /* {{{ */
 
 			zend_compile_typename(type_ast, arg_info);
 
+			if (arg_info->type_hint == IS_VOID) {
+				zend_error_noreturn(E_COMPILE_ERROR, "void cannot be used as a parameter type");
+			}
+
 			if (type_ast->kind == ZEND_AST_TYPE) {
 				if (arg_info->type_hint == IS_ARRAY) {
 					if (default_ast && !has_null_default
diff --git a/Zend/zend_execute.c b/Zend/zend_execute.c
index aa48b06767..044b49e760 100644
--- a/Zend/zend_execute.c
+++ b/Zend/zend_execute.c
@@ -946,6 +946,24 @@ static ZEND_COLD void zend_verify_internal_return_error(const zend_function *zf,
 		fclass, fsep, fname, need_msg, need_kind, returned_msg, returned_kind);
 }
 
+static ZEND_COLD void zend_verify_void_return_error(const zend_function *zf, const char *returned_msg, const char *returned_kind)
+{
+	const char *fname = ZSTR_VAL(zf->common.function_name);
+	const char *fsep;
+	const char *fclass;
+
+	if (zf->common.scope) {
+		fsep =  "::";
+		fclass = ZSTR_VAL(zf->common.scope->name);
+	} else {
+		fsep =  "";
+		fclass = "";
+	}
+
+	zend_type_error("%s%s%s() must not return a value, %s%s returned",
+		fclass, fsep, fname, returned_msg, returned_kind);
+}
+
 #if ZEND_DEBUG
 static int zend_verify_internal_return_type(zend_function *zf, zval *ret)
 {
@@ -975,6 +993,8 @@ static int zend_verify_internal_return_type(zend_function *zf, zval *ret)
 			} else if (ret_info->type_hint == _IS_BOOL &&
 			           EXPECTED(Z_TYPE_P(ret) == IS_FALSE || Z_TYPE_P(ret) == IS_TRUE)) {
 				/* pass */
+			} else if (ret_info->type_hint == IS_VOID) {
+				zend_verify_void_return_error(zf, zend_zval_type_name(ret), "");
 			} else {
 				/* Use strict check to verify return value of internal function */
 				zend_verify_internal_return_error(zf, "be of the type ", zend_get_type_by_const(ret_info->type_hint), zend_zval_type_name(ret), "");
@@ -1035,6 +1055,12 @@ static zend_always_inline void zend_verify_return_type(zend_function *zf, zval *
 			} else if (ret_info->type_hint == _IS_BOOL &&
 			           EXPECTED(Z_TYPE_P(ret) == IS_FALSE || Z_TYPE_P(ret) == IS_TRUE)) {
 				/* pass */
+			/* There would be a check here for the IS_VOID type hint, which
+			 * would trigger an error because a value had been returned.
+			 * However, zend_compile.c already does a compile-time check
+			 * that bans `return ...;` within a void function. Thus we can skip
+			 * this part of the runtime check for non-internal functions.
+			 */
 			} else if (UNEXPECTED(!zend_verify_scalar_type_hint(ret_info->type_hint, ret, ZEND_RET_USES_STRICT_TYPES()))) {
 				zend_verify_return_error(zf, "be of the type ", zend_get_type_by_const(ret_info->type_hint), zend_zval_type_name(ret), "");
 			}
@@ -1048,7 +1074,7 @@ static ZEND_COLD int zend_verify_missing_return_type(zend_function *zf, void **c
 	char *need_msg;
 	zend_class_entry *ce;
 
-	if (ret_info->type_hint) {
+	if (ret_info->type_hint && EXPECTED(ret_info->type_hint != IS_VOID)) {
 		if (ret_info->class_name) {
 			if (EXPECTED(*cache_slot)) {
 				ce = (zend_class_entry*)*cache_slot;
diff --git a/Zend/zend_types.h b/Zend/zend_types.h
index 9d15f498f8..805ea6d8c7 100644
--- a/Zend/zend_types.h
+++ b/Zend/zend_types.h
@@ -318,6 +318,7 @@ struct _zend_ast_ref {
 /* fake types */
 #define _IS_BOOL					13
 #define IS_CALLABLE					14
+#define IS_VOID						18
 
 /* internal types */
 #define IS_INDIRECT             	15