fix: enforce strict_map_key with object_pairs_hook

Author: KowalskiThomas

msgpack/fallback.py

@@ -518,9 +518,15 @@ def _unpack(self, execute=EX_CONSTRUCT):
                     self._unpack(EX_SKIP)
                 return
             if self._object_pairs_hook is not None:
-                ret = self._object_pairs_hook(
-                    (self._unpack(EX_CONSTRUCT), self._unpack(EX_CONSTRUCT)) for _ in range(n)
-                )
+
+                def _gen():
+                    for _ in range(n):
+                        key = self._unpack(EX_CONSTRUCT)
+                        if self._strict_map_key and type(key) not in (str, bytes):
+                            raise ValueError("%s is not allowed for map key" % str(type(key)))
+                        yield key, self._unpack(EX_CONSTRUCT)
+
+                ret = self._object_pairs_hook(_gen())
             else:
                 ret = {}
                 for _ in range(n):