Do not alter runtime types (#120)

Fixes #118 - Do not alter python runtime types on the fly

* Correctly create new parameterized types rather than modifying them in place.
* Have to use more than `typing.Iterable` now - hopefully this doesn't cause problems down the line, outside this package.
* Still, detect the move to `collections.abc.X` when there is a matching `typing.X`, and walk back to `typing.X`. This is needed to support earlier versions of python, and feels rather fragile!
* Fix up versions for github actions to avoid CI build depreciation warnings

.github/workflows/ci.yml

@@ -11,9 +11,9 @@ jobs:
   flake8:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Set up Python 3.8
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v4
         with:
           python-version: 3.8
       - name: Install dependencies
@@ -40,9 +40,9 @@ jobs:
         python-version: [3.7, 3.8, 3.9, "3.10", 3.11]
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python-version }}
       - name: Install dependencies
@@ -55,7 +55,7 @@ jobs:
           python -m pytest -r sx
       - name: Report coverage with Codecov
         if: github.event_name == 'push' && matrix.python-version == 3.9 && matrix.os == 'ubuntu-latest'
-        uses: codecov/codecov-action@v1
+        uses: codecov/codecov-action@v3
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           file: ./coverage.xml

.github/workflows/pypi.yaml

@@ -9,9 +9,9 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Set up Python
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v4
         with:
           python-version: 3.7
       - name: Install dependencies

func_adl/util_types.py

@@ -1,5 +1,6 @@
 import inspect
 import sys
+import typing
 from typing import Any, Dict, Optional, Tuple, Type, TypeVar
 
 if sys.version_info >= (3, 8):
@@ -25,9 +26,7 @@ def is_iterable(t: Type) -> bool:
 
 def _is_iterable_direct(t: Type) -> bool:
     "Is this type iterable?"
-    if getattr(t, "_name", None) == "Iterable":
-        return True
-    return False
+    return getattr(t, "_name", None) == "Iterable" or getattr(t, "__name__", None) == "Iterable"
 
 
 def get_inherited(t: Type) -> Type:
@@ -54,7 +53,18 @@ def get_inherited(t: Type) -> Type:
     g_args = get_args(t)
     if len(g_args) > 0:
         mapping = {a.__name__: v for a, v in zip(r.__parameters__, g_args)}
-        r.__args__ = tuple(_resolve_type(t_arg, mapping) for t_arg in get_args(r))
+
+        r_base = get_origin(r)
+        assert r_base is not None, "Internal error"
+
+        # Get us back to typing if this is a common interface.
+        # This is not needed in python 3.11 and forward, where
+        # collections.abc.X can are all be parameterized.
+        if r_base.__name__ in typing.__dict__:
+            r_base = typing.__dict__[r_base.__name__]
+
+        # Re-parameterize the type with the information e have from this parameterization.
+        r = r_base[tuple(_resolve_type(t_arg, mapping) for t_arg in get_args(r))]
 
     return r
 
@@ -117,7 +127,7 @@ def _resolve_type(t: Type, parameters: Dict[str, Type]) -> Optional[Type]:
     Returns:
         None if `t` is parameterized by unknown type var's
         The resolved type (a copy leaving `t` untouched) if TypeVar's are filled in
-        The type if no substition is required.
+        The type if no substitution is required.
     """
     if isinstance(t, TypeVar):
         if t.__name__ in parameters:

tests/test_util_types.py

@@ -89,7 +89,7 @@ class bogus(Iterable[T]):
 
     myc = bogus[int]
 
-    assert get_inherited(myc) == Iterable[int]
+    assert get_inherited(myc) == Iterable[int]  # type: ignore
 
 
 def test_get_inherited_two_levels():
@@ -106,6 +106,19 @@ class bogus2(bogus[Iterable[U]]):
     assert get_inherited(myc) == bogus[Iterable[int]]
 
 
+def test_get_inherited_generic_twice():
+    T = TypeVar("T")
+
+    class bogus(Iterable[T]):
+        pass
+
+    myc = bogus[int]
+    assert get_inherited(myc) == Iterable[int]  # type: ignore
+
+    myd = bogus[float]
+    assert get_inherited(myd) == Iterable[float]  # type: ignore
+
+
 def test_build_type_int():
     assert build_type_dict_from_type(int) == {}