zend_API: Do not overwrite readonly properties in object_properties_load()

[TimWolla]

Fixes #19765.

[nielsdos]

Looks good conceptually, but what about IS_PROP_UNINIT ?

[TimWolla]

but what about IS_PROP_UNINIT ?

I don't think this is necessary. It is only read for IS_UNDEF properties, which any overwritten property will no longer be. Setting the flag is only necessary when unsetting.

[nielsdos]

I don't think this is necessary. It is only read for IS_UNDEF properties, which any overwritten property will no longer be. Setting the flag is only necessary when unsetting.

Right indeed.

[iluuu1994]

LGTM! As mentioned privately, we should also unset the IS_PROP_UNINIT and IS_PROP_LAZY flags. However, the former is not consistently tracked on 8.3 anyway, and the latter only exists in 8.4. So this may be postponed. Lazy objects will also need more fixes to keep zend_lazy_object_info up to date.

[arnaud-lb]

Lazy objects should be ok as this is a helper for internal classes, and only objects of userland classes can be lazy.

[iluuu1994]

@arnaud-lb However, some internal classes are not final and may be overridden (e.g. many SPL classes). I do not know off the top of my head whether they can still be lazy though.

Edit: The answer is no. This is a non-issue then indeed!