[Python-checkins] cpython (3.5): Issue 24342: Let wrapper set by sys.set_coroutine_wrapper fail gracefully

Wed Jun 3 00:45:22 CEST 2015

https://hg.python.org/cpython/rev/19d613c2cd5f
changeset: 96483:19d613c2cd5f
branch: 3.5
parent: 96481:5c4ba50f6a57
user: Yury Selivanov <yselivanov at sprymix.com>
date: Tue Jun 02 18:43:51 2015 -0400
summary:
 Issue 24342: Let wrapper set by sys.set_coroutine_wrapper fail gracefully
files:
 Doc/library/sys.rst | 14 ++++++++
 Include/ceval.h | 3 +-
 Include/pystate.h | 1 +
 Lib/test/test_coroutines.py | 20 ++++++++++++
 Python/ceval.c | 39 +++++++++++++++++++-----
 Python/pystate.c | 1 +
 6 files changed, 68 insertions(+), 10 deletions(-)

diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst
--- a/Doc/library/sys.rst
+++ b/Doc/library/sys.rst
@@ -1085,6 +1085,20 @@
 If called twice, the new wrapper replaces the previous one. The function
 is thread-specific.
 
+ The *wrapper* callable cannot define new coroutines directly or indirectly::
+
+ def wrapper(coro):
+ async def wrap(coro):
+ return await coro
+ return wrap(coro)
+ sys.set_coroutine_wrapper(wrapper)
+
+ async def foo(): pass
+
+ # The following line will fail with a RuntimeError, because
+ # `wrapper` creates a `wrap(coro)` coroutine:
+ foo()
+
 See also :func:`get_coroutine_wrapper`.
 
 .. versionadded:: 3.5
diff --git a/Include/ceval.h b/Include/ceval.h
--- a/Include/ceval.h
+++ b/Include/ceval.h
@@ -23,8 +23,9 @@
 #ifndef Py_LIMITED_API
 PyAPI_FUNC(void) PyEval_SetProfile(Py_tracefunc, PyObject *);
 PyAPI_FUNC(void) PyEval_SetTrace(Py_tracefunc, PyObject *);
-PyAPI_FUNC(void) _PyEval_SetCoroutineWrapper(PyObject *wrapper);
+PyAPI_FUNC(void) _PyEval_SetCoroutineWrapper(PyObject *);
 PyAPI_FUNC(PyObject *) _PyEval_GetCoroutineWrapper(void);
+PyAPI_FUNC(PyObject *) _PyEval_ApplyCoroutineWrapper(PyObject *);
 #endif
 
 struct _frame; /* Avoid including frameobject.h */
diff --git a/Include/pystate.h b/Include/pystate.h
--- a/Include/pystate.h
+++ b/Include/pystate.h
@@ -135,6 +135,7 @@
 void *on_delete_data;
 
 PyObject *coroutine_wrapper;
+ int in_coroutine_wrapper;
 
 /* XXX signal handlers should also be here */
 
diff --git a/Lib/test/test_coroutines.py b/Lib/test/test_coroutines.py
--- a/Lib/test/test_coroutines.py
+++ b/Lib/test/test_coroutines.py
@@ -995,6 +995,26 @@
 sys.set_coroutine_wrapper(1)
 self.assertIsNone(sys.get_coroutine_wrapper())
 
+ def test_set_wrapper_3(self):
+ async def foo():
+ return 'spam'
+
+ def wrapper(coro):
+ async def wrap(coro):
+ return await coro
+ return wrap(coro)
+
+ sys.set_coroutine_wrapper(wrapper)
+ try:
+ with self.assertRaisesRegex(
+ RuntimeError,
+ "coroutine wrapper.*\.wrapper at 0x.*attempted to "
+ "recursively wrap <coroutine.*\.wrap"):
+
+ foo()
+ finally:
+ sys.set_coroutine_wrapper(None)
+
 
 class CAPITest(unittest.TestCase):
 
diff --git a/Python/ceval.c b/Python/ceval.c
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -3921,7 +3921,6 @@
 
 if (co->co_flags & CO_GENERATOR) {
 PyObject *gen;
- PyObject *coroutine_wrapper;
 
 /* Don't need to keep the reference to f_back, it will be set
 * when the generator is resumed. */
@@ -3935,14 +3934,9 @@
 if (gen == NULL)
 return NULL;
 
- if (co->co_flags & (CO_COROUTINE | CO_ITERABLE_COROUTINE)) {
- coroutine_wrapper = _PyEval_GetCoroutineWrapper();
- if (coroutine_wrapper != NULL) {
- PyObject *wrapped =
- PyObject_CallFunction(coroutine_wrapper, "N", gen);
- gen = wrapped;
- }
- }
+ if (co->co_flags & (CO_COROUTINE | CO_ITERABLE_COROUTINE))
+ return _PyEval_ApplyCoroutineWrapper(gen);
+
 return gen;
 }
 
@@ -4408,6 +4402,33 @@
 }
 
 PyObject *
+_PyEval_ApplyCoroutineWrapper(PyObject *gen)
+{
+ PyObject *wrapped;
+ PyThreadState *tstate = PyThreadState_GET();
+ PyObject *wrapper = tstate->coroutine_wrapper;
+
+ if (tstate->in_coroutine_wrapper) {
+ assert(wrapper != NULL);
+ PyErr_Format(PyExc_RuntimeError,
+ "coroutine wrapper %.150R attempted "
+ "to recursively wrap %.150R",
+ wrapper,
+ gen);
+ return NULL;
+ }
+
+ if (wrapper == NULL) {
+ return gen;
+ }
+
+ tstate->in_coroutine_wrapper = 1;
+ wrapped = PyObject_CallFunction(wrapper, "N", gen);
+ tstate->in_coroutine_wrapper = 0;
+ return wrapped;
+}
+
+PyObject *
 PyEval_GetBuiltins(void)
 {
 PyFrameObject *current_frame = PyEval_GetFrame();
diff --git a/Python/pystate.c b/Python/pystate.c
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -213,6 +213,7 @@
 tstate->on_delete_data = NULL;
 
 tstate->coroutine_wrapper = NULL;
+ tstate->in_coroutine_wrapper = 0;
 
 if (init)
 _PyThreadState_Init(tstate);
-- 
Repository URL: https://hg.python.org/cpython
