Merge pull request #184 from 0Hughman0/overloading-meta-attr

Overloading MetaAttr to improve type annotation.

.github/workflows/build-and-test.yml

@@ -44,6 +44,7 @@ jobs:
     - name: Typecheck with mypy
       run: |
         poetry run mypy cassini
+        poetry run mypy tests --exclude=tests/extensions/cassini_lib/mock_libraries/ --exclude=tests/project_cases
     - name: Upload coverage reports to Codecov
       uses: codecov/codecov-action@v3
       env:

binder/cas_project.py

@@ -1,4 +1,4 @@
-from cassini import Project, DEFAULT_TIERS
+from cassini import Project, DEFAULT_TIERS, WorkPackage
 
 project = Project(DEFAULT_TIERS, __file__)
 

cassini/meta.py

@@ -8,8 +8,7 @@
     Generic,
     KeysView,
     List,
-    Optional,
-    Mapping,
+    overload,
     TypeVar,
     Union,
     Literal,
@@ -288,6 +287,14 @@ def __set_name__(self, owner: object, name: str) -> None:
         if self.name is None:
             self.name = name
 
+    @overload
+    def __get__(self, instance: None, owner: object) -> Self:
+        pass
+
+    @overload
+    def __get__(self, instance: object, owner: object) -> AttrType:
+        pass
+
     def __get__(
         self, instance: Union[Any, None], owner: object
     ) -> Union[AttrType, Self]:

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "cassini"
-version = "0.3.0a12"
+version = "0.3.0a13"
 description = "A tool to structure experimental work, data and analysis using Jupyter Lab."
 authors = ["0Hughman0 <rammers2@hotmail.co.uk>"]
 license = "GPL-3.0-only"

tests/test_highlights.py

@@ -1,6 +1,6 @@
 import pytest # type: ignore[import]
 
-from cassini import DEFAULT_TIERS
+from cassini import DEFAULT_TIERS, Project
 from cassini.testing_utils import get_Project, patch_project
 
 @pytest.fixture
@@ -26,8 +26,8 @@ def mk_project(get_Project, tmp_path):
     return project
 
 
-def test_add_highlight(mk_project) -> None:
-    project: Project = mk_project
+def test_add_highlight(mk_project):
+    project = mk_project
 
     wp = project['WP1']
 

tests/test_meta.py

@@ -2,6 +2,8 @@
 import pathlib
 import datetime
 
+from typing_extensions import assert_type
+
 import pytest # type: ignore[import]
 from cassini import HomeTierBase, NotebookTierBase
 from cassini.meta import MetaAttr, Meta, MetaCache, MetaValidationError
@@ -134,6 +136,20 @@ def __init__(self):
     assert obj.with_default == 'squid'
 
 
+# this test has to be run with mypy... which is confusing.
+def test_meta_attr_inferred_types(tmp_path) -> None:
+    class MyClass:
+        a_str = MetaAttr(str, str)
+
+        def __init__(self):
+            self.meta = Meta.create_meta(tmp_path / 'meta.json', owner=self)
+
+    m = MyClass()
+
+    assert_type(m.a_str, str)
+    assert_type(MyClass.a_str, MetaAttr[str, str])
+
+
 def test_jsonable(mk_meta):
     meta = mk_meta