python
diff --git a/‎Lib/test/test__xxsubinterpreters.py‎
Lines changed: 6 additions & 5 deletions b/‎Lib/test/test__xxsubinterpreters.py‎
Lines changed: 6 additions & 5 deletions
diff --git a/‎Modules/_xxsubinterpretersmodule.c‎
Lines changed: 45 additions & 37 deletions b/‎Modules/_xxsubinterpretersmodule.c‎
Lines changed: 45 additions & 37 deletions
@@ -12,7 +12,6 @@
 from test import support
 from test.support import script_helper
 
-raise unittest.SkipTest("FIXME: bpo-33615: test crash on some CIs")
 
 interpreters = support.import_module('_xxsubinterpreters')
 
@@ -1317,17 +1316,19 @@ def test_run_string_arg_unresolved(self):
         self.assertEqual(obj, b'spam')
         self.assertEqual(out.strip(), 'send')
 
+    # XXX For now there is no high-level channel into which the
+    # sent channel ID can be converted...
+    # Note: this test caused crashes on some buildbots (bpo-33615).
+    @unittest.skip('disabled until high-level channels exist')
     def test_run_string_arg_resolved(self):
         cid = interpreters.channel_create()
         cid = interpreters._channel_id(cid, _resolve=True)
         interp = interpreters.create()
 
         out = _run_output(interp, dedent("""
             import _xxsubinterpreters as _interpreters
-            print(chan.end)
-            _interpreters.channel_send(chan, b'spam')
-            #print(chan.id.end)
-            #_interpreters.channel_send(chan.id, b'spam')
+            print(chan.id.end)
+            _interpreters.channel_send(chan.id, b'spam')
             """),
             dict(chan=cid.send))
         obj = interpreters.channel_recv(cid)
 
@@ -1000,11 +1000,11 @@ _channels_lookup(_channels *channels, int64_t id, PyThread_type_lock *pmutex)
 
     _channelref *ref = _channelref_find(channels->head, id, NULL);
     if (ref == NULL) {
-        PyErr_Format(ChannelNotFoundError, "channel %lld not found", id);
+        PyErr_Format(ChannelNotFoundError, "channel %" PRId64 " not found", id);
         goto done;
     }
     if (ref->chan == NULL || !ref->chan->open) {
-        PyErr_Format(ChannelClosedError, "channel %lld closed", id);
+        PyErr_Format(ChannelClosedError, "channel %" PRId64 " closed", id);
         goto done;
     }
 
@@ -1064,16 +1064,16 @@ _channels_close(_channels *channels, int64_t cid, _PyChannelState **pchan,
 
     _channelref *ref = _channelref_find(channels->head, cid, NULL);
     if (ref == NULL) {
-        PyErr_Format(ChannelNotFoundError, "channel %lld not found", cid);
+        PyErr_Format(ChannelNotFoundError, "channel %" PRId64 " not found", cid);
         goto done;
     }
 
     if (ref->chan == NULL) {
-        PyErr_Format(ChannelClosedError, "channel %lld closed", cid);
+        PyErr_Format(ChannelClosedError, "channel %" PRId64 " closed", cid);
         goto done;
     }
     else if (!force && end == CHANNEL_SEND && ref->chan->closing != NULL) {
-        PyErr_Format(ChannelClosedError, "channel %lld closed", cid);
+        PyErr_Format(ChannelClosedError, "channel %" PRId64 " closed", cid);
         goto done;
     }
     else {
@@ -1082,7 +1082,7 @@ _channels_close(_channels *channels, int64_t cid, _PyChannelState **pchan,
                     PyErr_ExceptionMatches(ChannelNotEmptyError)) {
                 if (ref->chan->closing != NULL) {
                     PyErr_Format(ChannelClosedError,
-                                 "channel %lld closed", cid);
+                                 "channel %" PRId64 " closed", cid);
                     goto done;
                 }
                 // Mark the channel as closing and return.  The channel
@@ -1144,7 +1144,7 @@ _channels_remove(_channels *channels, int64_t id, _PyChannelState **pchan)
     _channelref *prev = NULL;
     _channelref *ref = _channelref_find(channels->head, id, &prev);
     if (ref == NULL) {
-        PyErr_Format(ChannelNotFoundError, "channel %lld not found", id);
+        PyErr_Format(ChannelNotFoundError, "channel %" PRId64 " not found", id);
         goto done;
     }
 
@@ -1164,7 +1164,7 @@ _channels_add_id_object(_channels *channels, int64_t id)
 
     _channelref *ref = _channelref_find(channels->head, id, NULL);
     if (ref == NULL) {
-        PyErr_Format(ChannelNotFoundError, "channel %lld not found", id);
+        PyErr_Format(ChannelNotFoundError, "channel %" PRId64 " not found", id);
         goto done;
     }
     ref->objcount += 1;
@@ -1328,7 +1328,7 @@ _channel_send(_channels *channels, int64_t id, PyObject *obj)
     // Past this point we are responsible for releasing the mutex.
 
     if (chan->closing != NULL) {
-        PyErr_Format(ChannelClosedError, "channel %lld closed", id);
+        PyErr_Format(ChannelClosedError, "channel %" PRId64 " closed", id);
         PyThread_release_lock(mutex);
         return -1;
     }
@@ -1377,7 +1377,7 @@ _channel_recv(_channels *channels, int64_t id)
     PyThread_release_lock(mutex);
     if (data == NULL) {
         if (!PyErr_Occurred()) {
-            PyErr_Format(ChannelEmptyError, "channel %lld is empty", id);
+            PyErr_Format(ChannelEmptyError, "channel %" PRId64 " is empty", id);
         }
         return NULL;
     }
@@ -1527,13 +1527,13 @@ channelid_repr(PyObject *self)
     channelid *cid = (channelid *)self;
     const char *fmt;
     if (cid->end == CHANNEL_SEND) {
-        fmt = "%s(%lld, send=True)";
+        fmt = "%s(%" PRId64 ", send=True)";
     }
     else if (cid->end == CHANNEL_RECV) {
-        fmt = "%s(%lld, recv=True)";
+        fmt = "%s(%" PRId64 ", recv=True)";
     }
     else {
-        fmt = "%s(%lld)";
+        fmt = "%s(%" PRId64 ")";
     }
     return PyUnicode_FromFormat(fmt, name, cid->id);
 }
@@ -1542,7 +1542,7 @@ static PyObject *
 channelid_str(PyObject *self)
 {
     channelid *cid = (channelid *)self;
-    return PyUnicode_FromFormat("%lld", cid->id);
+    return PyUnicode_FromFormat("%" PRId64 "", cid->id);
 }
 
 PyObject *
@@ -1652,6 +1652,32 @@ channelid_richcompare(PyObject *self, PyObject *other, int op)
     Py_RETURN_FALSE;
 }
 
+static PyObject *
+_channel_from_cid(PyObject *cid, int end)
+{
+    PyObject *highlevel = PyImport_ImportModule("interpreters");
+    if (highlevel == NULL) {
+        PyErr_Clear();
+        highlevel = PyImport_ImportModule("test.support.interpreters");
+        if (highlevel == NULL) {
+            return NULL;
+        }
+    }
+    const char *clsname = (end == CHANNEL_RECV) ? "RecvChannel" :
+                                                  "SendChannel";
+    PyObject *cls = PyObject_GetAttrString(highlevel, clsname);
+    Py_DECREF(highlevel);
+    if (cls == NULL) {
+        return NULL;
+    }
+    PyObject *chan = PyObject_CallFunctionObjArgs(cls, cid, NULL);
+    Py_DECREF(cls);
+    if (chan == NULL) {
+        return NULL;
+    }
+    return chan;
+}
+
 struct _channelid_xid {
     int64_t id;
     int end;
@@ -1673,31 +1699,13 @@ _channelid_from_xid(_PyCrossInterpreterData *data)
     }
 
     /* Try returning a high-level channel end but fall back to the ID. */
-    PyObject *highlevel = PyImport_ImportModule("interpreters");
-    if (highlevel == NULL) {
-        PyErr_Clear();
-        highlevel = PyImport_ImportModule("test.support.interpreters");
-        if (highlevel == NULL) {
-            goto error;
-        }
-    }
-    const char *clsname = (xid->end == CHANNEL_RECV) ? "RecvChannel" :
-                                                       "SendChannel";
-    PyObject *cls = PyObject_GetAttrString(highlevel, clsname);
-    Py_DECREF(highlevel);
-    if (cls == NULL) {
-        goto error;
-    }
-    PyObject *chan = PyObject_CallFunctionObjArgs(cls, cid, NULL);
+    PyObject *chan = _channel_from_cid(cid, xid->end);
     if (chan == NULL) {
-        goto error;
+        PyErr_Clear();
+        return cid;
     }
     Py_DECREF(cid);
     return chan;
-
-error:
-    PyErr_Clear();
-    return cid;
 }
 
 static int
@@ -2048,14 +2056,14 @@ interpid_repr(PyObject *self)
     PyTypeObject *type = Py_TYPE(self);
     const char *name = _PyType_Name(type);
     interpid *id = (interpid *)self;
-    return PyUnicode_FromFormat("%s(%lld)", name, id->id);
+    return PyUnicode_FromFormat("%s(%" PRId64 ")", name, id->id);
 }
 
 static PyObject *
 interpid_str(PyObject *self)
 {
     interpid *id = (interpid *)self;
-    return PyUnicode_FromFormat("%lld", id->id);
+    return PyUnicode_FromFormat("%" PRId64 "", id->id);
 }
 
 PyObject *