Add type annotations (#341)

- Annotate the package.
- Annotate the tests.
- Run mypy in CI (in both Python 2 and Python 3 modes).
- Publish the types with `py.typed` files.

.coveragerc

@@ -7,3 +7,4 @@ omit=
 precision = 1
 exclude_lines =
   pragma: no cover
+  if TYPE_CHECKING:

.github/workflows/lint.yml

@@ -0,0 +1,22 @@
+name: Lint
+
+on:
+  push:
+    branches-ignore:
+      - "dependabot/**"
+  pull_request:
+
+jobs:
+  Lint:
+    name: 'Lint'
+    timeout-minutes: 10
+    runs-on: 'ubuntu-latest'
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Setup python
+        uses: actions/setup-python@v2
+        with:
+          python-version: '3.9'
+      - name: Run lint
+        run: ./lint.sh

lint-requirements.in

@@ -0,0 +1,6 @@
+# Typing
+mypy[python2]==0.910
+# TODO: Switch to cryptography>=35.0.0 once it's released.
+types-cryptography>=3.3.3
+types-pyopenssl>=20.0.4
+py>=1.9.0

lint-requirements.txt

@@ -0,0 +1,28 @@
+#
+# This file is autogenerated by pip-compile with python 3.9
+# To update, run:
+#
+#    pip-compile lint-requirements.in
+#
+mypy[python2]==0.910
+    # via -r lint-requirements.in
+mypy-extensions==0.4.3
+    # via mypy
+py==1.10.0
+    # via -r lint-requirements.in
+toml==0.10.2
+    # via mypy
+typed-ast==1.4.3
+    # via mypy
+types-cryptography==3.3.3
+    # via
+    #   -r lint-requirements.in
+    #   types-pyopenssl
+types-enum34==0.1.8
+    # via types-cryptography
+types-ipaddress==0.1.5
+    # via types-cryptography
+types-pyopenssl==20.0.4
+    # via -r lint-requirements.in
+typing-extensions==3.10.0.0
+    # via mypy

lint.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+
+set -exu -o pipefail
+
+python -c "import sys, struct, ssl; print('#' * 70); print('python:', sys.version); print('version_info:', sys.version_info); print('bits:', struct.calcsize('P') * 8); print('openssl:', ssl.OPENSSL_VERSION, ssl.OPENSSL_VERSION_INFO); print('#' * 70)"
+
+python -m pip install -U pip setuptools wheel
+python -m pip --version
+
+# Dependencies
+
+python -m pip install -Ur lint-requirements.txt
+
+# Linting
+
+mypy trustme tests
+mypy -2 trustme tests

newsfragments/339.feature.rst

@@ -0,0 +1 @@
+The package is now type annotated. If you use mypy on code which uses ``trustme``, you should be able to remove any exclusions.

pyproject.toml

@@ -17,3 +17,26 @@ directory = "newsfragments"
 underlines = ["-", "~", "^"]
 # Requires https://github.com/hawkowl/towncrier/pull/66
 issue_format = "`#{issue} <https://github.com/python-trio/trustme/issues/{issue}>`__"
+
+[tool.mypy]
+check_untyped_defs = true
+disallow_any_generics = true
+disallow_incomplete_defs = true
+disallow_subclassing_any = true
+disallow_untyped_calls = true
+disallow_untyped_decorators = true
+disallow_untyped_defs = true
+no_implicit_optional = true
+no_implicit_reexport = true
+show_error_codes = true
+strict_equality = true
+warn_redundant_casts = true
+warn_return_any = true
+warn_unreachable = true
+warn_unused_configs = true
+# Some ignores are only for python2/python3.
+# warn_unused_ignores = true
+
+[[tool.mypy.overrides]]
+module = "pytest"
+ignore_missing_imports = true

setup.py

@@ -13,6 +13,9 @@
     author_email="njs@pobox.com",
     license="MIT -or- Apache License 2.0",
     packages=find_packages(),
+    package_data={
+        'trustme': ['py.typed'],
+    },
     url="https://github.com/python-trio/trustme",
     install_requires=[
         "cryptography",

tests/test_cli.py

@@ -3,12 +3,18 @@
 import subprocess
 import sys
 
+import py
 import pytest
 
 from trustme._cli import main
 
+TYPE_CHECKING = False
+if TYPE_CHECKING:  # pragma: no cover
+    from typing import Any
+
 
 def test_trustme_cli(tmpdir):
+    # type: (py.path.local) -> None
     with tmpdir.as_cwd():
         main(argv=[])
 
@@ -18,6 +24,7 @@ def test_trustme_cli(tmpdir):
 
 
 def test_trustme_cli_e2e(tmpdir):
+    # type: (py.path.local) -> None
     with tmpdir.as_cwd():
         rv = subprocess.call([sys.executable, "-m", "trustme"])
         assert rv == 0
@@ -28,6 +35,7 @@ def test_trustme_cli_e2e(tmpdir):
 
 
 def test_trustme_cli_directory(tmpdir):
+    # type: (py.path.local) -> None
     subdir = tmpdir.mkdir("sub")
     main(argv=["-d", str(subdir)])
 
@@ -37,12 +45,14 @@ def test_trustme_cli_directory(tmpdir):
 
 
 def test_trustme_cli_directory_does_not_exist(tmpdir):
+    # type: (py.path.local) -> None
     notdir = tmpdir.join("notdir")
     with pytest.raises(ValueError, match="is not a directory"):
         main(argv=["-d", str(notdir)])
 
 
 def test_trustme_cli_identities(tmpdir):
+    # type: (py.path.local) -> None
     with tmpdir.as_cwd():
         main(argv=["-i", "example.org", "www.example.org"])
 
@@ -52,11 +62,13 @@ def test_trustme_cli_identities(tmpdir):
 
 
 def test_trustme_cli_identities_empty(tmpdir):
+    # type: (py.path.local) -> None
     with pytest.raises(ValueError, match="at least one identity"):
         main(argv=["-i"])
 
 
 def test_trustme_cli_common_name(tmpdir):
+    # type: (py.path.local) -> None
     with tmpdir.as_cwd():
         main(argv=["--common-name", "localhost"])
 
@@ -66,6 +78,7 @@ def test_trustme_cli_common_name(tmpdir):
 
 
 def test_trustme_cli_expires_on(tmpdir):
+    # type: (py.path.local) -> None
     with tmpdir.as_cwd():
         main(argv=["--expires-on", "2035-03-01"])
 
@@ -75,6 +88,7 @@ def test_trustme_cli_expires_on(tmpdir):
 
 
 def test_trustme_cli_invalid_expires_on(tmpdir):
+    # type: (py.path.local) -> None
     with tmpdir.as_cwd():
         with pytest.raises(ValueError, match="does not match format"):
             main(argv=["--expires-on", "foobar"])
@@ -85,6 +99,7 @@ def test_trustme_cli_invalid_expires_on(tmpdir):
 
 
 def test_trustme_cli_quiet(capsys, tmpdir):
+    # type: (Any, py.path.local) -> None
     with tmpdir.as_cwd():
         main(argv=["-q"])