Translate errors in thread.local.__getattr__ to AttributeErrors

src/runtime/builtin_modules/thread.cpp

@@ -175,7 +175,12 @@ public:
         Box* tls_obj = getThreadLocalObject(obj);
         if (!strcmp(name, "__dict__"))
             return tls_obj;
-        return getitem(tls_obj, boxString(name));
+
+        try {
+            return getitem(tls_obj, boxString(name));
+        } catch (ExcInfo e) {
+            raiseExcHelper(AttributeError, "'%.50s' object has no attribute '%.400s'", obj->cls->tp_name, name);
+        }
     }
 
     static Box* hash(Box* obj) { return boxInt(PyThread_get_thread_ident()); }

src/runtime/dict.cpp

@@ -232,9 +232,11 @@ extern "C" PyObject* PyDict_GetItem(PyObject* dict, PyObject* key) noexcept {
     try {
         return getitem(dict, key);
     } catch (ExcInfo e) {
-        if (e.matches(KeyError))
-            return NULL;
-        abort();
+        // PyDict_GetItem has special error behavior in CPython for backwards-compatibility reasons,
+        // and apparently it's important enough that we have to follow that.
+        // The behavior is that all errors get suppressed, and in fact I think it's supposed to
+        // restore the previous exception afterwards (we don't do that yet).
+        return NULL;
     }
 }
 

test/tests/threading_local.py

@@ -12,3 +12,4 @@ thread.start()
 thread.join()
 
 print a.x
+print getattr(a, "doesnt_exist", 5)