Compile error on MacOS with C++ extension when using ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX

[dktapps]

Description

https://github.com/pmmp/ext-morton/blob/2532e9f09d3bc6f6975d78b6632086b894dcef75/morton.cpp#L45

This code compiles fine with GCC on Ubuntu 20.04 on 8.3.0RC1, but fails on MacOS with clang with the following errors:

/Users/runner/work/PHP-Binaries/PHP-Binaries/install_data/subdir/php/ext/morton/morton.cpp:45:1: error: expected '(' for function-style cast or type construction
ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_morton2d_encode, 0, 2, IS_LONG, 0)
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Users/runner/work/PHP-Binaries/PHP-Binaries/install_data/subdir/php/Zend/zend_API.h:202:2: note: expanded from macro 'ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX'
        ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX2(name, return_reference, required_num_args, type, allow_null, 0)
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Users/runner/work/PHP-Binaries/PHP-Binaries/install_data/subdir/php/Zend/zend_API.h:199:50: note: expanded from macro 'ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX2'
                { (const char*)(uintptr_t)(required_num_args), ZEND_TYPE_INIT_CODE(type, allow_null, _ZEND_ARG_INFO_FLAGS(return_reference, 0, is_tentative_return_type)), NULL },
                                                               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Users/runner/work/PHP-Binaries/PHP-Binaries/install_data/subdir/php/Zend/zend_types.h:287:2: note: expanded from macro 'ZEND_TYPE_INIT_CODE'
        ZEND_TYPE_INIT_MASK(((code) == _IS_BOOL ? MAY_BE_BOOL : ( (code) == IS_ITERABLE ? _ZEND_TYPE_ITERABLE_BIT : ((code) == IS_MIXED ? MAY_BE_ANY : (1 << (code))))) \
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Users/runner/work/PHP-Binaries/PHP-Binaries/install_data/subdir/php/Zend/zend_types.h:284:20: note: expanded from macro 'ZEND_TYPE_INIT_MASK'
        _ZEND_TYPE_PREFIX { NULL, (_type_mask) }
        ~~~~~~~~~~~~~~~~~ ^
/Users/runner/work/PHP-Binaries/PHP-Binaries/install_data/subdir/php/ext/morton/morton.cpp:46:2: error: expected '(' for function-style cast or type construction
        ZEND_ARG_TYPE_INFO(0, x, IS_LONG, 0)
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Users/runner/work/PHP-Binaries/PHP-Binaries/install_data/subdir/php/Zend/zend_API.h:135:11: note: expanded from macro 'ZEND_ARG_TYPE_INFO'
        { #name, ZEND_TYPE_INIT_CODE(type_hint, allow_null, _ZEND_ARG_INFO_FLAGS(pass_by_ref, 0, 0)), NULL },
                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Users/runner/work/PHP-Binaries/PHP-Binaries/install_data/subdir/php/Zend/zend_types.h:287:2: note: expanded from macro 'ZEND_TYPE_INIT_CODE'
        ZEND_TYPE_INIT_MASK(((code) == _IS_BOOL ? MAY_BE_BOOL : ( (code) == IS_ITERABLE ? _ZEND_TYPE_ITERABLE_BIT : ((code) == IS_MIXED ? MAY_BE_ANY : (1 << (code))))) \
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Users/runner/work/PHP-Binaries/PHP-Binaries/install_data/subdir/php/Zend/zend_types.h:284:20: note: expanded from macro 'ZEND_TYPE_INIT_MASK'
        _ZEND_TYPE_PREFIX { NULL, (_type_mask) }
        ~~~~~~~~~~~~~~~~~ ^

I believe this problem was caused by a change in #11978.

PHP Version

8.3.0RC1

Operating System

MacOS 11 (GitHub Actions)

[iluuu1994]

@kocsismate Can you take a look?

[Girgias]

Considering the intl extensions compiles just fine on MacOS, the only difference is that it defines the arg infos in an autogenerated header file.

So maybe the new macro _ZEND_TYPE_PREFIX to fix the Windows issue is causing some weird CPP issues?

[dktapps]

Not sure which Windows issue you're referring to, as I've been compiling the linked C++ extension on Windows and *nix for years across several different PHP versions with no issues.

If the intl arginfos are included inside an extern "C", that would likely explain the difference in behaviour.

[Girgias]

Not sure which Windows issue you're referring to, as I've been compiling the linked C++ extension on Windows and *nix for years across several different PHP versions with no issues.

If the intl arginfos are included inside an extern "C", that would likely explain the difference in behaviour.

I am talking about the introduction of:

/* FIXME: We could add (zend_type) here at some point but this breaks in MSVC because
 * (zend_type)(zend_type){} is no longer considered constant. */
# define _ZEND_TYPE_PREFIX

Which as far as I can see was introduced because of a MSVC issue, and MSVC is the Windows compiler.

But yes, they include the arginfos via an extern "C" {}

[dktapps]

The empty macro appears to be working correct. The other branch under #ifdef __cplusplus is the problem.

[kocsismate]

The empty macro appears to be working correct. The other branch under #ifdef __cplusplus is the problem.

Thanks for the confirmation ! I guess we have to make it only apply to MSVC.

[dktapps]

I'm just a little puzzled as to what this new macro actually fixes. As I said, the C++ extension I linked has been compiled with MSVC, clang and gcc on Linux, MacOS and Windows for several years, and had no issues without this macro.

I found this commit in the PR that added it, but I don't see any specifics on what exactly it fixed: 62341c0

[kocsismate]

Finally, I found it: https://github.com/php/php-src/actions/runs/5442753605/job/14732712171#step:7:1318

D:\a\php-src\php-src\ext\intl\timezone\timezone_arginfo.h(177): error C4576: a parenthesized type followed by an initializer list is a non-standard explicit type conversion syntax (compiling source file ext\intl\timezone\timezone_class.cpp)

For reference: the following line made untyped constants and properties use the construct unsupported by MSVC: https://github.com/php/php-src/pull/10170/files#diff-5df7a541a3649c4a1ad7870312ebdcd836b6c36dc1dc65c8fda8271c210e014dR2267 (line 2267 in gen_stub.php) The test failure appeared when I merged my original PR to master (#10170). On the other hand, the build was green on PHP-8.2. Then the PR was reverted, and the new one was applied along with Ilija's fix a few weeks later.

[Girgias]

Okay so the need for this type macro prefix is only when we include the arg infos in an extern C in a C++ file for MSVC?

I wonder if it makes more sense to move the arginfo includes out of the extern C for intl and see if we can remove the macro altogether?

[iluuu1994]

I'm not sure if that helps. AFAIK (not knowing C++ at all), designated initializers are a g++ extension, until C++20 where they have finally been standardized with C compatibility. The usual way to initialize structs in C++ is struct_name { ... }, hence the marco. MS doesn't support many extensions in C/C++, that's likely the cause for this failure.