Pin a dev version of the mypy-typemap prototype, run some tests against it (#111)

Author: msullivan

README.md

@@ -5,12 +5,19 @@ This is the development repository for
 which proposes TypeScript-inspired type-level introspection and construction
 facilities for the Python type system.
 
+This repository contains an implementation of the proposed additions
+to ``typing`` ([typemap/typing.py](typemap/typing.py)), exported as
+the module ``typemap_extensions``.
+
+It also contains a **prototype** runtime evaluator
+([typemap/type_eval](typemap/type_eval)).
+
 Discussion of the PEP is at the
 [PEP 827 discussion thread](https://discuss.python.org/t/pep-827-type-manipulation/106353).
 
-This repository also contains an implementation of the proposed
-additions to ``typing`` ([typemap/typing.py](typemap/typing.py)), as well as a
-**prototype** runtime evaluator ([typemap/type_eval](typemap/type_eval)).
+A prototype typechecker implementation lives at
+https://github.com/msullivan/mypy-typemap and is a test dependency of
+this repo.
 
 ## Development
 
@@ -21,9 +28,11 @@ additions to ``typing`` ([typemap/typing.py](typemap/typing.py)), as well as a
 
 ## Running the typechecker
 
-If you have https://github.com/msullivan/mypy/tree/typemap active in a
-venv, you can run it against at least some of the tests with
-invocations like:
-  `mypy --python-version=3.14 tests/test_qblike_2.py`
+The prototype mypy can be run from this repo with `uv run mypy`.
+Stubs are set up so that importing ``typemap_extensions`` will do the
+right thing.
+
+`uv run pytest tests/test_mypy_proto.py` will run the mypy prototype
+against a supported subset of test files.
 
-Not all of them run cleanly yet though.
+You can also run the prototype mypy directly on a file with `uv run mypy <file>`

pyproject.toml

@@ -13,7 +13,7 @@ include = ["typemap", "typemap.*", "typemap_extensions"]
 test = [
     "pytest>=7.0",
     "ruff",
-    "mypy==1.18.1",
+    "mypy @ git+https://github.com/msullivan/mypy-typemap@f49083e5cd7124df93ea1a0a844d60adf901c250",
 ]
 
 [tool.uv]

scripts/update-mypy-pin

@@ -0,0 +1,19 @@
+#!/bin/bash
+set -e
+
+MYPY_DIR="${1:-../mypy}"
+
+if [ ! -d "$MYPY_DIR/.git" ]; then
+    echo "error: $MYPY_DIR is not a git repository" >&2
+    exit 1
+fi
+
+REV=$(git -C "$MYPY_DIR" rev-parse HEAD)
+echo "Pinning mypy to $REV (from $MYPY_DIR)"
+
+sed -i "s|mypy @ git+https://github.com/msullivan/mypy-typemap@[a-f0-9]*|mypy @ git+https://github.com/msullivan/mypy-typemap@$REV|" pyproject.toml
+
+uv sync
+
+git add pyproject.toml uv.lock
+git commit -m "Pin mypy to mypy-typemap@${REV:0:12}"

tests/test_astlike_1.py

@@ -1,3 +1,5 @@
+# SKIP MYPY: runs forever! must debug
+
 import pytest
 import typing
 

tests/test_call.py

@@ -17,7 +17,8 @@
 def func[*T, K: BaseTypedDict](
     *args: Unpack[T],
     **kwargs: Unpack[K],
-) -> NewProtocol[*[Member[c.name, int] for c in Iter[Attrs[K]]]]: ...
+) -> NewProtocol[*[Member[c.name, int] for c in Iter[Attrs[K]]]]:
+    raise NotImplementedError
 
 
 def test_call_1():

tests/test_cqa.py

@@ -15,7 +15,6 @@ def project_root() -> pathlib.Path:
 
 def test_cqa_ruff_check(project_root):
     """Test that code passes ruff linting checks."""
-    # Ruff respects pyproject.toml configuration and exclusions
     result = subprocess.run(
         [sys.executable, "-m", "ruff", "check", "."],
         capture_output=True,
@@ -32,7 +31,6 @@ def test_cqa_ruff_check(project_root):
 
 def test_cqa_ruff_format_check(project_root):
     """Test that code is properly formatted according to ruff."""
-    # Ruff format respects pyproject.toml exclusions
     result = subprocess.run(
         [sys.executable, "-m", "ruff", "format", "--check", "."],
         capture_output=True,
@@ -48,26 +46,23 @@ def test_cqa_ruff_format_check(project_root):
 
 
 def test_cqa_mypy(project_root):
-    """Test that code passes mypy type checking."""
-    # Mypy uses configuration from pyproject.toml
-    # Run on typemap -- tests not ready yet
-    for subdir in ["typemap"]:
-        result = subprocess.run(
-            [
-                sys.executable,
-                "-m",
-                "mypy",
-                "--config-file",
-                project_root / "pyproject.toml",
-                subdir,
-            ],
-            capture_output=True,
-            text=True,
-            cwd=project_root,
-        )
+    """Test that typemap/ passes mypy type checking."""
+    result = subprocess.run(
+        [
+            sys.executable,
+            "-m",
+            "mypy",
+            "--config-file",
+            project_root / "pyproject.toml",
+            "typemap",
+        ],
+        capture_output=True,
+        text=True,
+        cwd=project_root,
+    )
 
-        if result.returncode != 0:
-            output = result.stdout
-            if result.stderr:
-                output += "\n\n" + result.stderr
-            pytest.fail(f"mypy validation failed:\n{output}", pytrace=False)
+    if result.returncode != 0:
+        output = result.stdout
+        if result.stderr:
+            output += "\n\n" + result.stderr
+        pytest.fail(f"mypy validation failed:\n{output}", pytrace=False)

tests/test_dataclass_like.py

@@ -4,7 +4,6 @@
     ReadOnly,
     TypedDict,
     Never,
-    Self,
 )
 
 import typemap_extensions as typing
@@ -54,7 +53,7 @@ class Field[T: FieldArgs](typing.InitField[T]):
     Literal["__init__"],
     Callable[
         typing.Params[
-            typing.Param[Literal["self"], Self],
+            typing.Param[Literal["self"], T],
             *[
                 typing.Param[
                     p.name,
@@ -80,7 +79,6 @@ class Field[T: FieldArgs](typing.InitField[T]):
     *[x for x in typing.Iter[typing.Members[T]]],
 ]
 
-
 """
 
 ``UpdateClass`` can then be used to create a class decorator (a la
@@ -95,7 +93,7 @@ def dataclass_ish[T](
     # Add the computed __init__ function
     InitFnType[T],
 ]:
-    pass
+    raise NotImplementedError
 
 
 """
@@ -112,7 +110,7 @@ def __init_subclass__[T](
         # Add the computed __init__ function
         InitFnType[T],
     ]:
-        super().__init_subclass__()
+        pass
 
 
 # End PEP section

tests/test_eval_call_with_types.py

@@ -1,3 +1,5 @@
+# SKIP MYPY
+
 import pytest
 
 from typing import Callable, Generic, Literal, Self, TypeVar

tests/test_fastapilike_1.py

@@ -1,3 +1,6 @@
+# SKIP MYPY: Invalid use of Self
+# TODO: resolve
+
 # We should have at least *one* test with this...
 from __future__ import annotations
 
@@ -71,7 +74,9 @@ class _Default:
 
 type AddInit[T] = NewProtocol[
     InitFnType[T],
-    *Members[T],
+    # TODO: mypy rejects this -- should it work?
+    # *Members[T],
+    *[t for t in Iter[Members[T]]],
 ]
 
 # Strip `| None` from a type by iterating over its union components

tests/test_fastapilike_2.py

@@ -1,3 +1,6 @@
+# SKIP MYPY: Invalid use of Self
+# TODO: resolve
+
 from typing import (
     Callable,
     Literal,