Stackless issue python#246: fix assertion errors caused by test_outside

Calling test_outside from a non main tasklet didn't work.

(cherry picked from commit 877f2c7)

Author: Anselm Kruis

Stackless/module/stacklessmodule.c

@@ -969,6 +969,9 @@ test_outside(PyObject *self)
 {
     PyThreadState *ts = PyThreadState_GET();
     PyTaskletObject *stmain = ts->st.main;
+    if (PyTasklet_Scheduled(stmain) && !PyTasklet_IsCurrent(stmain))
+        RUNTIME_ERROR("main tasklet is still scheduled", NULL);
+    PyTaskletObject *current;
     PyCStackObject *initial_stub = ts->st.initial_stub;
     PyFrameObject *f = SLP_CURRENT_FRAME(ts);
     int recursion_depth = ts->recursion_depth;
@@ -989,7 +992,7 @@ test_outside(PyObject *self)
     ts->st.nesting_level = 0;
     SLP_SET_CURRENT_FRAME(ts, NULL);
     ts->recursion_depth = 0;
-    slp_current_remove();
+    current = slp_current_remove();
     while (ts->st.runcount > 0) {
         Py_DECREF(ret);
         ret = PyStackless_Schedule(Py_None, 0);
@@ -1004,7 +1007,7 @@ test_outside(PyObject *self)
     Py_CLEAR(ts->st.initial_stub);
     ts->st.initial_stub = initial_stub;
     SLP_SET_CURRENT_FRAME(ts, f);
-    slp_current_insert(stmain);
+    slp_current_insert(current);
     ts->recursion_depth = recursion_depth;
     ts->st.nesting_level = nesting_level;
     ts->st.serial_last_jump = jump;

Stackless/unittests/test_outside.py

@@ -155,6 +155,19 @@ def run():
             raise self.result
         self.assertIs(self.result, False)
 
+    def test_call_from_non_main_tasklet(self):
+        done = False
+        def task():
+            nonlocal done
+            done = True
+
+        stackless.tasklet(task)()
+        stackless.tasklet(stackless.test_outside)().switch()
+        self.assertTrue(done)
+
+    def test_call_from_non_main_tasklet2(self):
+        self.assertRaisesRegex(RuntimeError, "main tasklet is still scheduled", stackless.tasklet(stackless.test_outside)().run)
+
 
 class TestCframe(StacklessTestCase):
     n = 100