Check for array-iness in Python de-jsonization

aas_core_codegen/python/jsonization/_generate.py

@@ -185,6 +185,63 @@ def {function_name}(
     )
 
 
+def _generate_is_array_like() -> Stripped:
+    """Generate the function to check that the jsonable is an array-like object."""
+    return Stripped(
+        f'''\
+def _try_to_cast_to_array_like(
+{I}jsonable: Jsonable
+) -> Optional[Iterable[Any]]:
+{I}"""
+{I}Try to cast the ``jsonable`` to something like a JSON array.
+
+{I}In particular, we explicitly check that the ``jsonable`` is not a mapping, as we
+{I}do not want to mistake dictionaries (*i.e.* de-serialized JSON objects) for lists.
+
+{I}>>> assert _try_to_cast_to_array_like(True) is None
+
+{I}>>> assert _try_to_cast_to_array_like(0) is None
+
+{I}>>> assert _try_to_cast_to_array_like(2.2) is None
+
+{I}>>> assert _try_to_cast_to_array_like("hello") is None
+
+{I}>>> assert _try_to_cast_to_array_like(b"hello") is None
+
+{I}>>> _try_to_cast_to_array_like([1, 2])
+{I}[1, 2]
+
+{I}>>> assert _try_to_cast_to_array_like({{"a": 3}}) is None
+
+{I}>>> assert _try_to_cast_to_array_like(collections.OrderedDict()) is None
+
+{I}>>> _try_to_cast_to_array_like(range(1, 2))
+{I}range(1, 2)
+
+{I}>>> _try_to_cast_to_array_like((1, 2))
+{I}(1, 2)
+
+{I}>>> assert _try_to_cast_to_array_like({{1, 2, 3}}) is None
+{I}"""
+{I}if (
+{II}
+{II}not isinstance(jsonable, (str, bytearray, bytes))
+{II}and hasattr(jsonable, "__iter__")
+{II}and not hasattr(jsonable, "keys")
+{II}# NOTE (mristin):
+{II}# There is no easy way to check for sets as opposed to sequence except
+{II}# for checking for direct inheritance. A sequence also inherits from
+{II}# a collection, so both sequences and sets provide ``__contains__`` method.
+{II}#
+{II}# See: https://docs.python.org/3/library/collections.abc.html
+{II}and not isinstance(jsonable, collections.abc.Set)
+{I}):
+{II}return cast(Iterable[Any], jsonable)
+
+{I}return None'''
+    )
+
+
 def _generate_dispatch_map_for_abstract_class(
     cls: intermediate.AbstractClass,
 ) -> Stripped:
@@ -466,23 +523,24 @@ def ignore(self, jsonable: Jsonable) -> None:
 
             body = Stripped(
                 f"""\
-if not isinstance(jsonable, collections.abc.Iterable):
+array_like = _try_to_cast_to_array_like(jsonable)
+if array_like is None:
 {I}raise DeserializationException(
-{II}f"Expected an iterable, but got: {{type(jsonable)}}"
+{II}f"Expected something array-like, but got: {{type(jsonable)}}"
 {I})
 
 items: List[
 {I}{items_type}
 ] = []
-for i, jsonable_item in enumerate(jsonable):
+for i, jsonable_item in enumerate(array_like):
 {I}try:
 {II}item = {parse_function}(
 {III}jsonable_item
 {II})
 {I}except DeserializationException as exception:
 {II}exception.path._prepend(
 {III}IndexSegment(
-{IIII}jsonable,
+{IIII}array_like,
 {IIII}i
 {III})
 {II})
@@ -1047,6 +1105,7 @@ def generate(
 import collections.abc
 import sys
 from typing import (
+{I}cast,
 {I}Any,
 {I}Callable,
 {I}Iterable,
@@ -1205,6 +1264,7 @@ class DeserializationException(Exception):
         _generate_float_from_jsonable(),
         _generate_str_from_jsonable(),
         _generate_bytes_from_jsonable(),
+        _generate_is_array_like(),
     ]  # type: List[Stripped]
 
     errors = []  # type: List[Error]