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muglugnikic
muglug
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nikic
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Implement never return type
The never type can be used to indicate that a function never returns, for example because it always unwinds. RFC: https://wiki.php.net/rfc/noreturn_type Closes GH-6761.
1 parent 6adfe9d commit 6cd0b48

32 files changed

Lines changed: 888 additions & 509 deletions

‎UPGRADING‎

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@@ -151,6 +151,8 @@ PHP 8.1 UPGRADE NOTES
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RFC: https://wiki.php.net/rfc/array_unpacking_string_keys
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. Added support for enumerations.
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RFC: https://wiki.php.net/rfc/enumerations
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. Added support for never return type
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RFC: https://wiki.php.net/rfc/noreturn_type
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- Curl:
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. Added CURLOPT_DOH_URL option.

‎Zend/Optimizer/dce.c‎

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@@ -155,6 +155,7 @@ static inline bool may_have_side_effects(
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case ZEND_TICKS:
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case ZEND_YIELD:
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case ZEND_YIELD_FROM:
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case ZEND_VERIFY_NEVER_TYPE:
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/* Intrinsic side effects */
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return 1;
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case ZEND_DO_FCALL:

‎Zend/Optimizer/pass1.c‎

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@@ -676,6 +676,7 @@ void zend_optimizer_pass1(zend_op_array *op_array, zend_optimizer_ctx *ctx)
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case ZEND_COALESCE:
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case ZEND_ASSERT_CHECK:
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case ZEND_JMP_NULL:
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case ZEND_VERIFY_NEVER_TYPE:
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collect_constants = 0;
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break;
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}

‎Zend/Optimizer/zend_cfg.c‎

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@@ -301,6 +301,7 @@ ZEND_API int zend_build_cfg(zend_arena **arena, const zend_op_array *op_array, u
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case ZEND_GENERATOR_RETURN:
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case ZEND_EXIT:
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case ZEND_MATCH_ERROR:
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case ZEND_VERIFY_NEVER_TYPE:
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if (i + 1 < op_array->last) {
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BB_START(i + 1);
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}
@@ -515,6 +516,7 @@ ZEND_API int zend_build_cfg(zend_arena **arena, const zend_op_array *op_array, u
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case ZEND_EXIT:
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case ZEND_THROW:
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case ZEND_MATCH_ERROR:
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case ZEND_VERIFY_NEVER_TYPE:
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break;
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case ZEND_JMP:
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block->successors_count = 1;

‎Zend/Optimizer/zend_dump.c‎

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@@ -471,6 +471,9 @@ ZEND_API void zend_dump_op(const zend_op_array *op_array, const zend_basic_block
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case IS_VOID:
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fprintf(stderr, " (void)");
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break;
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case IS_NEVER:
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fprintf(stderr, " (never)");
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break;
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default:
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fprintf(stderr, " (\?\?\?)");
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break;

‎Zend/tests/return_types/never_allowed.phpt‎

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@@ -0,0 +1,29 @@
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--TEST--
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never return type: acceptable cases
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--FILE--
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<?php
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function foo(): never {
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throw new Exception('bad');
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}
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try {
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foo();
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} catch (Exception $e) {
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// do nothing
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}
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function calls_foo(): never {
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foo();
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}
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try {
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calls_foo();
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} catch (Exception $e) {
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// do nothing
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}
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echo "OK!", PHP_EOL;
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?>
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--EXPECT--
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OK!

‎Zend/tests/return_types/never_covariance.phpt‎

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@@ -0,0 +1,78 @@
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--TEST--
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never return type: acceptable covariance cases
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--FILE--
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<?php
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class A
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{
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public function foo(): string
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{
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return "hello";
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}
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public function bar(): never
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{
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throw new UnexpectedValueException('parent');
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}
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public function &baz()
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{
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}
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public function someReturningStaticMethod() : static
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{
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}
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}
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class B extends A
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{
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public function foo(): never
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{
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throw new UnexpectedValueException('bad');
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}
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public function bar(): never
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{
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throw new UnexpectedValueException('child');
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}
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public function &baz(): never
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{
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throw new UnexpectedValueException('child');
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}
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public function someReturningStaticMethod(): never
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{
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throw new UnexpectedValueException('child');
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}
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}
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try {
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(new B)->foo();
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} catch (UnexpectedValueException $e) {
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// do nothing
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}
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try {
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(new B)->bar();
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} catch (UnexpectedValueException $e) {
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// do nothing
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}
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try {
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(new B)->baz();
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} catch (UnexpectedValueException $e) {
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// do nothing
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}
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try {
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(new B)->someReturningStaticMethod();
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} catch (UnexpectedValueException $e) {
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// do nothing
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}
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echo "OK!", PHP_EOL;
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?>
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--EXPECT--
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OK!

‎Zend/tests/return_types/never_disallowed1.phpt‎

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@@ -0,0 +1,13 @@
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--TEST--
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never return type: unacceptable cases: any return
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--FILE--
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<?php
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function foo(): never {
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return "hello"; // not permitted in a never function
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}
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// Note the lack of function call: function validated at compile-time
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?>
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--EXPECTF--
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Fatal error: A never-returning function must not return in %s on line %d

‎Zend/tests/return_types/never_disallowed2.phpt‎

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@@ -0,0 +1,13 @@
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--TEST--
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never return type: unacceptable cases: empty return
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--FILE--
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<?php
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function foo(): never {
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return; // not permitted in a never function
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}
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// Note the lack of function call: function validated at compile-time
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?>
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--EXPECTF--
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Fatal error: A never-returning function must not return in %s on line %d

‎Zend/tests/return_types/never_disallowed3.phpt‎

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@@ -0,0 +1,19 @@
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--TEST--
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never return type: unacceptable cases: implicit return
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--FILE--
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<?php
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function foo(): never {
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if (false) {
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throw new Exception('bad');
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}
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}
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foo();
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?>
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--EXPECTF--
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Fatal error: Uncaught TypeError: foo(): never-returning function must not implicitly return in %s:%d
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Stack trace:
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#0 %s(%d): foo()
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#1 {main}
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thrown in %s on line %d

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