Fix build for Python 3.5 (ac3d96a7) · Commits · Kirill Smelkov / wendelin.core

still it refers _PyThreadState_Current thus it fails in Python 3.5.1 like this :

In file included from bigfile/_bigfile.c:37:0:
./include/wendelin/compat_py2.h: In function ‘_PyThreadState_UncheckedGet’:
./include/wendelin/compat_py2.h:66:5: warning: implicit declaration of function ‘_Py_atomic_load_relaxed’ [-Wimplicit-function-declaration]
     return (PyThreadState*)_Py_atomic_load_relaxed(&_PyThreadState_Current);
     ^
./include/wendelin/compat_py2.h:66:53: error: ‘_PyThreadState_Current’ undeclared (first use in this function)
     return (PyThreadState*)_Py_atomic_load_relaxed(&_PyThreadState_Current);
                                                     ^
./include/wendelin/compat_py2.h:66:53: note: each undeclared identifier is reported only once for each function it appears in
./include/wendelin/compat_py2.h:67:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^

like https://github.com/vmprof/vmprof-python/commit/b8a237cc8bdfa06f9e2c09cdf1740865f950d82e the following will make the build pass :

--- a/include/wendelin/compat_py2.h
+++ b/include/wendelin/compat_py2.h
@@ -61,6 +61,10 @@ static inline PyThreadState * _PyThreadState_UncheckedGet(void)
 /* _PyThreadState_UncheckedGet was added in CPython 3.5.2rc1
  * https://github.com/python/cpython/commit/df858591 */
 #elif PY_VERSION_HEX < 0x03050200
+#if !defined(_Py_atomic_load_relaxed)
+void *volatile _PyThreadState_Current;
+#define Py_atomic_loard_relaxed(pp) (*(pp))
+#endif
 static inline PyThreadState * _PyThreadState_UncheckedGet(void)
 {
     return (PyThreadState*)_Py_atomic_load_relaxed(&_PyThreadState_Current);

@kazuhiko thanks for feedback. Yes there is a small window 3.5.1 - 3.5.2rc1, when

there is no direct access to _PyThreadState_Current and no access to python atomic functions, and
_PyThreadState_UncheckedGet() is not yet added to python.

So instead of adding flaky support for that time window, my idea is that we just ask 3.5 users to upgrade to >= 3.5.2.

We can add a protection to wendelin.core which, if seeing 3.5 python series, refuses to compile and asks to upgrade python.

Requiring minor upgrade is reasonable to me.

it still does not work with the diff above ...

$ python -m 'wendelin.bigarray.array_zodb'
Traceback (most recent call last):
  File "/home/kazuhiko/anaconda3/lib/python3.5/runpy.py", line 170, in _run_module_as_main
    "__main__", mod_spec)
  File "/home/kazuhiko/anaconda3/lib/python3.5/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/home/kazuhiko/anaconda3/lib/python3.5/site-packages/wendelin.core-0.6-py3.5-linux-x86_64.egg/wendelin/bigarray/array_zodb.py", line 26, in <module>
    from wendelin.bigfile.file_zodb import ZBigFile, LivePersistent
  File "/home/kazuhiko/anaconda3/lib/python3.5/site-packages/wendelin.core-0.6-py3.5-linux-x86_64.egg/wendelin/bigfile/__init__.py", line 22, in <module>
    from ._bigfile import BigFile, WRITEOUT_STORE, WRITEOUT_MARKSTORED, ram_reclaim
ImportError: /home/kazuhiko/anaconda3/lib/python3.5/site-packages/wendelin.core-0.6-py3.5-linux-x86_64.egg/wendelin/bigfile/_bigfile.cpython-35m-x86_64-linux-gnu.so: undefined symbol: _Py_atomic_load_relaxed

my idea is that we just ask 3.5 users to upgrade to >= 3.5.2.

I agree. Since 3.5.2 is already released, adding code, that is only required for 3.5.1, is not so good idea.

For usage with anaconda, I can survive by downgrading to Python 3.5.0, until 3.5.3 version is released.

Thanks !

3.5.3 => 3.5.2 I mean, of course...

@kazuhiko thanks for feedback. I've amended the commit and it is e6beab19 now.

The interdiff is:

diff --git a/include/wendelin/compat_py2.h b/include/wendelin/compat_py2.h
index dd35ba1..519e261 100644
--- a/include/wendelin/compat_py2.h
+++ b/include/wendelin/compat_py2.h
@@ -58,13 +58,22 @@ static inline PyThreadState * _PyThreadState_UncheckedGet(void)
 {
     return _PyThreadState_Current;
 }
-/* _PyThreadState_UncheckedGet was added in CPython 3.5.2rc1
- * https://github.com/python/cpython/commit/df858591 */
-#elif PY_VERSION_HEX < 0x03050200
+/* _PyThreadState_UncheckedGet() was added in CPython 3.5.2rc1
+ * https://github.com/python/cpython/commit/df858591
+ *
+ * During CPython 3.5.0 - 3.5.rc1 there is a window when
+ * - public access to pyatomics was removed, and
+ * - _PyThreadState_UncheckedGet() was not added yet
+ *
+ * https://bugs.python.org/issue25150
+ * https://bugs.python.org/issue26154 */
+#elif PY_VERSION_HEX < 0x03050000
 static inline PyThreadState * _PyThreadState_UncheckedGet(void)
 {
     return (PyThreadState*)_Py_atomic_load_relaxed(&_PyThreadState_Current);
 }
+#elif PY_VERSION_HEX < 0x03050200
+# error "You are using CPython 3.5.X series. Upgrade your CPython to >= 3.5.2 to get _PyThreadState_UncheckedGet() support."
 #endif
 
 #endif

Hope it is reasonably ok and we push to master to nexedi/

mentioned in issue nexedi/wendelin.core#1 (closed)

@@ -262,6 +262,7 @@ setup(
         Programming Language :: Python :: 2.7
         Programming Language :: Python :: 3
         Programming Language :: Python :: 3.4
         Programming Language :: Python :: 3.5
         Programming Language :: Python :: Implementation :: CPython
         Topic :: Software Development :: Libraries :: Python Modules
         Framework :: ZODB\
-...

 # wendelin.core | tox setup
 [tox]
 envlist = py27-ZODB3-{zblk0,zblk1}-{fs,zeo,neo}-{numpy110,numpy111}, {py27,py34}-ZODB4-{zblk0,zblk1}-{fs,zeo}-{numpy110,numpy111}
 envlist = py27-ZODB3-{zblk0,zblk1}-{fs,zeo,neo}-{numpy110,numpy111}, {py27,py34,py35}-ZODB4-{zblk0,zblk1}-{fs,zeo}-{numpy110,numpy111}
 # (NOTE ZODB3 does not work on python3)
 # (NOTE NEO does not work on ZODB4)
-...