bpo-33615: Re-enable a subinterpreter test. (gh-7251)

For bpo-32604 I added extra subinterpreter-related tests (see #6914), which caused a few buildbots to crash. This patch fixes the crash by ensuring that refcounts in channels are handled properly.

1 files changed, 4 insertions, 3 deletions

diff --git a/Include/internal/pystate.h b/Include/internal/pystate.h
index da642c6..70e0666 100644
--- a/Include/internal/pystate.h
+++ b/Include/internal/pystate.h
@@ -80,7 +80,7 @@ struct _xid;
 
 // _PyCrossInterpreterData is similar to Py_buffer as an effectively
 // opaque struct that holds data outside the object machinery.  This
-// is necessary to pass between interpreters in the same process.
+// is necessary to pass safely between interpreters in the same process.
 typedef struct _xid {
     // data is the cross-interpreter-safe derivation of a Python object
     // (see _PyObject_GetCrossInterpreterData).  It will be NULL if the
@@ -89,8 +89,9 @@ typedef struct _xid {
     // obj is the Python object from which the data was derived.  This
     // is non-NULL only if the data remains bound to the object in some
     // way, such that the object must be "released" (via a decref) when
-    // the data is released.  In that case it is automatically
-    // incref'ed (to match the automatic decref when releaed).
+    // the data is released.  In that case the code that sets the field,
+    // likely a registered "crossinterpdatafunc", is responsible for
+    // ensuring it owns the reference (i.e. incref).
     PyObject *obj;
     // interp is the ID of the owning interpreter of the original
     // object.  It corresponds to the active interpreter when