3.12.0b1: static declaration follows non-static when importing internal/pycore_dict.h

[P403n1x87]

Bug report

I have a change within a project that includes a native extension which fails to compile with 3.12.0b1:

      In file included from echion/coremodule.cc:22:
      In file included from ./echion/dict.h:7:
      In file included from /Users/gabriele/.pyenv/versions/3.12.0b1/include/python3.12/internal/pycore_dict.h:13:
      In file included from /Users/gabriele/.pyenv/versions/3.12.0b1/include/python3.12/internal/pycore_runtime.h:16:
      In file included from /Users/gabriele/.pyenv/versions/3.12.0b1/include/python3.12/internal/pycore_global_objects.h:11:
      /Users/gabriele/.pyenv/versions/3.12.0b1/include/python3.12/internal/pycore_gc.h:84:19: error: static declaration of 'PyObject_GC_IsFinalized' follows non-static declaration
      static inline int _PyGC_FINALIZED(PyObject *op) {
                        ^
      /Users/gabriele/.pyenv/versions/3.12.0b1/include/python3.12/cpython/objimpl.h:85:30: note: expanded from macro '_PyGC_FINALIZED'
      #  define _PyGC_FINALIZED(o) PyObject_GC_IsFinalized(o)
                                   ^
      /Users/gabriele/.pyenv/versions/3.12.0b1/include/python3.12/objimpl.h:209:17: note: previous declaration is here
      PyAPI_FUNC(int) PyObject_GC_IsFinalized(PyObject *);

I didn't look too deep into what changed here, but my guess would be that the macro should drop the _ prefix, i.e.

#  define PyGC_FINALIZED(o) PyObject_GC_IsFinalized(o)

since it seems that PyObject_GC_IsFinalized is part of the API. The same code compiles fine with older versions of Python.

Your environment

MacOS Ventura 13.3.1
Python 3.12.0b1

Linked PRs

• gh-105268: Remove _PyGC_FINALIZED() macro #105350
• gh-105268: Add _Py_FROM_GC() function to pycore_gc.h #105362
• [3.12] gh-105268: Remove _PyGC_FINALIZED() macro (#105350) #107348
• gh-105268: _PyGC_FINALIZED() removal is already documented in 3.12 #107350

[sunmy2019]

You are including internal headers which is not allowed. You should never define Py_BUILD_CORE.

/* Defines to build Python and its standard library:
 *
 * - Py_BUILD_CORE: Build Python core. Give access to Python internals, but
 *   should not be used by third-party modules.
 * - Py_BUILD_CORE_BUILTIN: Build a Python stdlib module as a built-in module.
 * - Py_BUILD_CORE_MODULE: Build a Python stdlib module as a dynamic library.
 *
 * Py_BUILD_CORE_BUILTIN and Py_BUILD_CORE_MODULE imply Py_BUILD_CORE.
 *
 * On Windows, Py_BUILD_CORE_MODULE exports "PyInit_xxx" symbol, whereas
 * Py_BUILD_CORE_BUILTIN does not.
 */

Thus, you will never see this function:

      static inline int _PyGC_FINALIZED(PyObject *op) {

---

Say if you are really relying on some internal things, make sure you have defined Py_BUILD_CORE for all headers.

Then you will never see this definition:

      #  define _PyGC_FINALIZED(o) PyObject_GC_IsFinalized(o)

---

P.S. I have found no dict.h in your repo.

[P403n1x87]

Say if you are really relying on some internal things, make sure you have defined Py_BUILD_CORE for all headers.

I really do need these internal structures. So this means that the fact it used to work for older versions of Python is just a mere accident. Correct? I'll try defining Py_BUILD_CORE in all my headers and see what happens 🤞 . Just wanted to call this out in case it was the symptom of an actual issue, since this worked with previous minor releases.

P.S. I have found no dict.h in your repo.

The change with the #include <internal/pycore_dict.h> lives in a local branch that I haven't pushed yet.

[iritkatriel]

CC @vstinner .

[vstinner]

  include/python3.12/cpython/objimpl.h:85:30: note: expanded from macro '_PyGC_FINALIZED'
      #  define _PyGC_FINALIZED(o) PyObject_GC_IsFinalized(o)

It seems like the Python.h header was included before the Py_BUILD_CORE macro was defined, and the internal/pycore_gc.h header was included after the Py_BUILD_CORE macro was defined.

Well, this old macro is causing the trouble here. It should just be removed: I wrote PR #105350 for that.

You should be able to work around the issue by defining the Py_BUILD_CORE macro earlier.

[vstinner]

I removed the macro. Thanks for your reminder :-) I close the issue.