package/php-lua: fix build with GCC14

On Buildroot 2025.02.x, php-lua build fails on the following error:

lua.c:862:44: error: assignment to 'zend_object_write_property_t' {aka 'struct _zval_struct * (*)(struct _zend_object *, struct _zend_string *, struct _zval_struct *, void **)'} from incompatible pointer type 'void (*)(zval *, zval *, zval *, void **)' {aka 'void (*)(struct _zval_struct *, struct _zval_struct *, struct _zval_struct *, void **)'} [-Wincompatible-pointer-types]
862 | lua_object_handlers.write_property =
php_lua_write_property;
| ^
lua.c:863:44: error: assignment to 'zend_object_read_property_t' {aka 'struct _zval_struct * (*)(struct _zend_object *, struct _zend_string *, int, void **, struct _zval_struct *)'} from incompatible pointer type 'zval * (*)(zval *, zval *, int, void **, zval *)' {aka 'struct _zval_struct * (*)(struct _zval_struct *, struct _zval_struct *, int, void **, struct _zval_struct *)'} [-Wincompatible-pointer-types]
863 | lua_object_handlers.read_property =
php_lua_read_property;
| ^
make[2]: *** [Makefile:214: lua.lo] Error 1

This issue is still present on the upstream repository, but it has been fixed on one of its forks. Bring the relevant patch from the fork to allow building php-lua.

---
I've taken a look at the official upstream to make the fix integrated in here as well, but it really looks like a dead end: there has been no activity for 5 years, and the maintainer does not seem to answer PRs or issues. The PR containing the two patches introduced with the BR package has not even been merged. I have been tempted to replace the upstream source with the fork from which I took the patch
(https://github.com/badoo/php-lua), which looks slightly less "dead" (last activity 2 years ago, and some work done to update the module compatibility with current PHP major version). I eventually chose to keep the current upstream and bring this single patch, but please let me know if changing the upstream source would be better.

---
 ...-write-properly-read-property-was-changed.patch | 77 ++++++++++++++++++++++
 1 file changed, 77 insertions(+)

new file mode 100644
index 0000000000000000000000000000000000000000..0c68a7062451d40a2d630c24244ab003bdfb9396
@@ -0,0 +1,77 @@
+From de1068d634519abf2461dac9427b5ff24b6603af Mon Sep 17 00:00:00 2001
+From: Mikhail Galanin <[email protected]>
+Date: Tue, 24 Aug 2021 08:28:47 +0100
+Subject: [PATCH] php8: Signature of write_property/read_property was changed
+ in https://github.com/php/php-src/commit/91ef4124e56
+
+Taken from https://github.com/badoo/php-lua/pull/8
+Signed-off-by: Alexis Lothoré <[email protected]>
+---
+ lua.c | 28 ++++++++++++++--------------
+ 1 file changed, 14 insertions(+), 14 deletions(-)
+
+diff --git a/lua.c b/lua.c
+index edc2868..32c1471 100755
+--- a/lua.c
++++ b/lua.c
+@@ -229,46 +229,46 @@ zend_object *php_lua_create_object(zend_class_entry *ce)
+ 
+ /** {{{ static zval * php_lua_read_property(zval *object, zval *member, int type)
+ */
+-zval *php_lua_read_property(zval *object, zval *member, int type, void **cache_slot, zval *rv){
+-	lua_State *L = (Z_LUAVAL_P(object))->L;
+-	zend_string *str_member;
++zval *php_lua_read_property(zend_object *object, zend_string *member, int type, void **cache_slot, zval *rv){
++	lua_State *L = php_lua_obj_from_obj(object)->L;
+ 
+ 	if (type != BP_VAR_R) {
+ 		ZVAL_NULL(rv);
+ 		return rv;
+ 	}
+ 
+-	str_member = zval_get_string(member);
+ #if (LUA_VERSION_NUM < 502)
+-	lua_getfield(L, LUA_GLOBALSINDEX, ZSTR_VAL(str_member));
++	lua_getfield(L, LUA_GLOBALSINDEX, ZSTR_VAL(member));
+ #else
+-	lua_getglobal(L, ZSTR_VAL(str_member));
++	lua_getglobal(L, ZSTR_VAL(member));
+ #endif
+-	zend_string_release(str_member);
+ 
+-	php_lua_get_zval_from_lua(L, -1, object, rv);
++	zval lua_zval_object;
++	ZVAL_OBJ(&lua_zval_object, object);
++
++	php_lua_get_zval_from_lua(L, -1, &lua_zval_object, rv);
+ 	lua_pop(L, 1);
++
+ 	return rv;
+ }
+ /* }}} */
+ 
+ /** {{{ static void php_lua_write_property(zval *object, zval *member, zval *value)
+ */
+-static void php_lua_write_property(zval *object, zval *member, zval *value, void ** key) {
+-	lua_State *L = (Z_LUAVAL_P(object))->L;
+-	zend_string *str_member = zval_get_string(member);
++static zval* php_lua_write_property(zend_object *object, zend_string *member, zval *value, void ** key) {
++	lua_State *L = php_lua_obj_from_obj(object)->L;
+ 
+ #if (LUA_VERSION_NUM < 502)
+-	php_lua_send_zval_to_lua(L, member);
++	lua_pushlstring(L, ZSTR_VAL(val), ZSTR_LEN(val));
+ 	php_lua_send_zval_to_lua(L, value);
+ 
+ 	lua_settable(L, LUA_GLOBALSINDEX);
+ #else
+ 	php_lua_send_zval_to_lua(L, value);
+-	lua_setglobal(L, Z_STRVAL_P(member));
++	lua_setglobal(L, ZSTR_VAL(member));
+ #endif
+ 
+-	zend_string_release(str_member);
++	return value;
+ }
+ /* }}} */
+ 

---
base-commit: 2fd520c8d52b9e0ed5e26343813fdd8dbcadb45f
change-id: 20250806-php-lua-39895d4fe179

Best regards,

Alexis Lothoré, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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Hello Alexis,

Buildroot 2025.02.x is one thing, but do you also see the same build issue on master?

Since there's no build failure in our autobuilder (which is kind of surprising), could you include in the commit log a snippet of a reasonably minimal defconfig that exhibits the issue?

Also, do you know what caused the failure? I would suspect an update of PHP.

It's of course annoying to have unmaintained things packaged in Buildroot. I guess Nicolas is still using this software component?

Thomas

Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com
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Hi Thomas,

Yes, I have the build failure on top of master as well (on top of 2fd520c8d52b ("package/glm: bump version to 1.0.1"), to be precise)

Sure, I'll include it in the next revision. It looks like this:

BR2_arm=y
BR2_cortex_a9=y
BR2_ARM_ENABLE_NEON=y
BR2_ARM_ENABLE_VFP=y
BR2_ARM_FPU_NEON=y
BR2_TOOLCHAIN_EXTERNAL=y
BR2_TOOLCHAIN_EXTERNAL_BOOTLIN=y
BR2_PACKAGE_LUA=y
BR2_PACKAGE_PHP=y
BR2_PACKAGE_PHP_LUA=y
BR2_PACKAGE_PHP_PECL_DBUS=y

If I trust the upstream pending PR, the failure is due to commit 91ef4124e56a ("Refactor zend_object_handlers API to pass zend_object* and zend_string* insted of zval(s).") in upstream PHP project. I fail to find the corresponding entry in any PHP changelog, but following the git history, this has been introduced with PHP 8.0.0. I tried to quickly revert to PHP 7.4.20, but this version does not even build anymore on current BR (unrelated build failures)

However I observe that if I switch from Bootlin 'bleeding edge' toolchain to 'stable' toolchain, php-lua build succeeds on master. So I guess this issue is a mix of API change and compiler update. When using the stable toolchain, I see the warning that matches the error I see when using the bleeding-edge toolchain (-Wincompatible-pointer-types)

Alexis Lothoré, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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Hello Alexis,

As pointed out in my other e-mail replying to your other patch, this definitely sounds like a GCC 15.x related issue, where GCC 15.x enabled more checks, causing a hard build failure where "simple" warnings were emitted earlier.

Thomas

Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com
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