Switch mypy approach to pre-commit (#1234)

I'm treating my PR to mypy bazel integration as dead in the water. Abandoning that approach, this seems to work reasonably well as a replacement. It's actually a slightly newer version of mypy too -- the bazel integration was stuck on an old version.

Note I don't think we're losing much: we shouldn't be writing too much python.

.pre-commit-config.yaml

@@ -85,6 +85,35 @@ repos:
     rev: cbeb4c9c4137cff1568659fcc48e8b85cddd0c8d # frozen: 4.0.1
     hooks:
       - id: flake8
+  - repo: https://github.com/pre-commit/mirrors-mypy
+    rev: 'v0.950'
+    hooks:
+      - id: mypy
+        args:
+          - --disallow-untyped-decorators
+          - --warn-unused-configs
+          - --disallow-subclassing-any
+          - --disallow-untyped-calls
+          - --disallow-untyped-defs
+          - --disallow-incomplete-defs
+          - --check-untyped-defs
+          - --no-implicit-optional
+          - --warn-redundant-casts
+          - --warn-unused-ignores
+          - --warn-return-any
+          - --pretty
+        # This should match the requirements added in the WORKSPACE pip_install.
+        additional_dependencies:
+          - gql >= 2.0.0, < 3.0.0
+          - PyGitHub
+        # TODO: should probably fix gen_rtti.
+        exclude: |
+          (?x)^(
+              explorer/gen_rtti\.py|
+              proposals/.*|
+              .*/lit\.cfg\.py|
+              .*_test\.py
+          )$
   - repo: https://github.com/codespell-project/codespell
     rev: 01da43d753cdff4ea7dff952b4f5317450af31e3 # frozen: v2.1.0
     hooks:

WORKSPACE

@@ -30,53 +30,6 @@ pip_install(
     requirements = "//github_tools:requirements.txt",
 )
 
-###############################################################################
-# Python mypy rules
-###############################################################################
-
-# NOTE: https://github.com/bazelbuild/bazel/issues/4948 tracks bazel supporting
-# typing directly. If it's added, we will probably want to switch.
-
-# Add mypy
-mypy_integration_version = "e5f8071f33eca637cd90bf70cb45f749e63bf2ca"
-
-# TODO: Can switch back to the official repo when it includes:
-# https://github.com/thundergolfer/bazel-mypy-integration/pull/43
-#http_archive(
-#    name = "mypy_integration",
-#    sha256 = "621df076709dc72809add1f5fe187b213fee5f9b92e39eb33851ab13487bd67d",
-#    strip_prefix = "bazel-mypy-integration-%s" % mypy_integration_version,
-#    urls = [
-#        "https://github.com/thundergolfer/bazel-mypy-integration/archive/refs/tags/%s.tar.gz" % mypy_integration_version,
-#    ],
-#)
-
-http_archive(
-    name = "mypy_integration",
-    sha256 = "481ec6f0953a84a36b8103286f04c4cd274ae689060099085c02ac187d007592",
-    strip_prefix = "bazel-mypy-integration-%s" % mypy_integration_version,
-    urls = [
-        "https://github.com/jonmeow/bazel-mypy-integration/archive/%s.zip" % mypy_integration_version,
-    ],
-)
-
-load(
-    "@mypy_integration//repositories:repositories.bzl",
-    mypy_integration_repositories = "repositories",
-)
-
-mypy_integration_repositories()
-
-load("@mypy_integration//:config.bzl", "mypy_configuration")
-
-mypy_configuration("//bazel/mypy:mypy.ini")
-
-load("@mypy_integration//repositories:deps.bzl", mypy_integration_deps = "deps")
-
-mypy_integration_deps(
-    mypy_requirements_file = "//bazel/mypy:version.txt",
-)
-
 ###############################################################################
 # C++ rules
 ###############################################################################

bazel/check_deps/BUILD

@@ -2,8 +2,6 @@
 # Exceptions. See /LICENSE for license information.
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-load("@mypy_integration//:mypy.bzl", "mypy_test")
-
 # The filegroups establishing root rules for `genquery` invocations can be
 # updated by running:
 #
@@ -38,22 +36,3 @@ py_test(
     data = [":non_test_cc_deps.txt"],
     main = "check_non_test_cc_deps.py",
 )
-
-mypy_test(
-    name = "check_non_test_cc_deps_mypy_test",
-    include_imports = True,
-    deps = [":check_non_test_cc_deps"],
-)
-
-# Note that this script expects to be run directly and not via Bazel as it in
-# turn invokes Bazel.
-py_binary(
-    name = "update_roots",
-    srcs = ["update_roots.py"],
-)
-
-mypy_test(
-    name = "update_roots_mypy_test",
-    include_imports = True,
-    deps = [":update_roots"],
-)

bazel/mypy/BUILD

@@ -1,5 +0,0 @@
-# Part of the Carbon Language project, under the Apache License v2.0 with LLVM
-# Exceptions. See /LICENSE for license information.
-# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-
-# Empty BUILD file to allow access to Bazel extensions.

bazel/mypy/mypy.ini

@@ -1,18 +0,0 @@
-# Part of the Carbon Language project, under the Apache License v2.0 with LLVM
-# Exceptions. See /LICENSE for license information.
-# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-
-[mypy]
-disallow_untyped_decorators = true
-warn_unused_configs = true
-disallow_subclassing_any = true
-disallow_untyped_calls = true
-disallow_untyped_defs = true
-disallow_incomplete_defs = true
-check_untyped_defs = true
-no_implicit_optional = true
-warn_redundant_casts = true
-warn_unused_ignores = true
-warn_return_any = true
-ignore_missing_imports = false
-pretty = true

bazel/mypy/version.txt

@@ -1,7 +0,0 @@
-# Part of the Carbon Language project, under the Apache License v2.0 with LLVM
-# Exceptions. See /LICENSE for license information.
-# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-
-# Synced with:
-# https://github.com/thundergolfer/bazel-mypy-integration/blob/master/third_party/requirements.txt
-mypy==0.790

explorer/BUILD

@@ -2,8 +2,6 @@
 # Exceptions. See /LICENSE for license information.
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-load("@mypy_integration//:mypy.bzl", "mypy_test")
-
 package(default_visibility = [
     "//bazel/check_deps:__pkg__",
     "//explorer:__subpackages__",
@@ -43,17 +41,3 @@ py_binary(
     name = "gen_rtti",
     srcs = ["gen_rtti.py"],
 )
-
-# This script should be run directly; the target is only provided for the
-# mypy_test.
-py_binary(
-    name = "update_checks_mypy_wrapper",
-    srcs = ["update_checks.py"],
-    main = "update_checks.py",
-)
-
-mypy_test(
-    name = "update_checks_mypy_test",
-    include_imports = True,
-    deps = [":update_checks_mypy_wrapper"],
-)

explorer/syntax/BUILD

@@ -2,8 +2,6 @@
 # Exceptions. See /LICENSE for license information.
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-load("@mypy_integration//:mypy.bzl", "mypy_test")
-
 package(default_visibility = [
     "//explorer:__pkg__",
     "//explorer/fuzzing:__pkg__",
@@ -139,12 +137,6 @@ py_test(
     deps = ["format_grammar_lib"],
 )
 
-mypy_test(
-    name = "format_grammar_mypy_test",
-    include_imports = True,
-    deps = [":format_grammar_lib"],
-)
-
 cc_test(
     name = "unimplemented_example_test",
     srcs = ["unimplemented_example_test.cpp"],

github_tools/BUILD

@@ -3,7 +3,6 @@
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
 load("@py_deps//:requirements.bzl", "requirement")
-load("@mypy_integration//:mypy.bzl", "mypy_test")
 
 py_library(
     name = "github_helpers",
@@ -25,12 +24,6 @@ py_binary(
     deps = ["github_helpers"],
 )
 
-mypy_test(
-    name = "pr_comments_mypy_test",
-    include_imports = True,
-    deps = [":pr_comments"],
-)
-
 py_test(
     name = "pr_comments_test",
     srcs = ["pr_comments_test.py"],
@@ -48,12 +41,6 @@ py_binary(
     ],
 )
 
-mypy_test(
-    name = "update_label_access_mypy_test",
-    include_imports = True,
-    deps = [":update_label_access"],
-)
-
 py_test(
     name = "update_label_access_test",
     srcs = ["update_label_access_test.py"],

github_tools/github_helpers.py

@@ -14,8 +14,8 @@ import os
 from typing import Dict, Generator, Optional, Tuple
 
 # https://pypi.org/project/gql/
-import gql
-import gql.transport.requests
+import gql  # type: ignore
+import gql.transport.requests  # type: ignore
 
 _ENV_TOKEN = "GITHUB_ACCESS_TOKEN"
 
@@ -52,7 +52,7 @@ class Client(object):
             url="https://api.github.com/graphql",
             headers={"Authorization": "bearer %s" % parsed_args.access_token},
         )
-        self._client = gql.Client(transport=transport)  # type: ignore
+        self._client = gql.Client(transport=transport)
 
     def execute(self, query: str) -> Dict:
         """Runs a query."""

github_tools/pr_comments.py

@@ -25,6 +25,7 @@ except ImportError:
         "github_helpers",
         os.path.join(os.path.dirname(__file__), "github_helpers.py"),
     )
+    assert github_helpers_spec is not None
     github_helpers = importlib.util.module_from_spec(github_helpers_spec)
     github_helpers_spec.loader.exec_module(github_helpers)  # type: ignore
 

github_tools/update_label_access.py

@@ -114,18 +114,18 @@ def _update_team(
 
     This switches to pygithub because GraphQL lacks equivalent mutation support.
     """
-    gh_team = gh.get_organization(_ORG).get_team_by_slug(_TEAM)  # type: ignore
+    gh_team = gh.get_organization(_ORG).get_team_by_slug(_TEAM)
     add_members = org_members - team_members
     if add_members:
         print("Adding members: %s" % ", ".join(add_members))
         for member in add_members:
-            gh_team.add_membership(gh.get_user(member))  # type: ignore
+            gh_team.add_membership(gh.get_user(member))
 
     remove_members = team_members - org_members
     if remove_members:
         print("Removing members: %s" % ", ".join(remove_members))
         for member in remove_members:
-            gh_team.remove_membership(gh.get_user(member))  # type: ignore
+            gh_team.remove_membership(gh.get_user(member))
 
 
 def main() -> None:
@@ -136,7 +136,7 @@ def main() -> None:
     org_members = _load_org_members(client)
     team_members = _load_team_members(client)
     if org_members != team_members:
-        gh = github.Github(parsed_args.access_token)  # type: ignore
+        gh = github.Github(parsed_args.access_token)
         _update_team(gh, org_members, team_members)
     print("Done!")
 

migrate_cpp/BUILD

@@ -2,8 +2,6 @@
 # Exceptions. See /LICENSE for license information.
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-load("@mypy_integration//:mypy.bzl", "mypy_test")
-
 py_binary(
     name = "migrate_cpp",
     srcs = ["migrate_cpp.py"],
@@ -13,9 +11,3 @@ py_binary(
     ],
     python_version = "PY3",
 )
-
-mypy_test(
-    name = "migrate_cpp_mypy_test",
-    include_imports = True,
-    deps = [":migrate_cpp"],
-)

proposals/scripts/BUILD

@@ -2,8 +2,6 @@
 # Exceptions. See /LICENSE for license information.
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-load("@mypy_integration//:mypy.bzl", "mypy_test")
-
 py_binary(
     name = "new_proposal",
     srcs = ["new_proposal.py"],
@@ -17,9 +15,3 @@ py_test(
     python_version = "PY3",
     deps = [":new_proposal"],
 )
-
-mypy_test(
-    name = "new_proposal_mypy_test",
-    include_imports = True,
-    deps = [":new_proposal"],
-)

scripts/BUILD

@@ -1,100 +0,0 @@
-# Part of the Carbon Language project, under the Apache License v2.0 with LLVM
-# Exceptions. See /LICENSE for license information.
-# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-
-load("@mypy_integration//:mypy.bzl", "mypy_test")
-
-py_library(
-    name = "scripts_utils",
-    srcs = ["scripts_utils.py"],
-)
-
-# Note that this Python script is intended to be run directly, and not through
-# Bazel. We have a rule for it so we can type check it.
-py_binary(
-    name = "create_compdb",
-    testonly = 1,
-    srcs = ["create_compdb.py"],
-    deps = [":scripts_utils"],
-)
-
-mypy_test(
-    name = "create_compdb_mypy_test",
-    include_imports = True,
-    deps = [":create_compdb"],
-)
-
-# Note that this Python script is intended to be run directly, and not through
-# Bazel. We have a rule for it so we can type check it.
-py_binary(
-    name = "fix_cc_deps",
-    testonly = 1,
-    srcs = ["fix_cc_deps.py"],
-    deps = [":scripts_utils"],
-)
-
-mypy_test(
-    name = "fix_cc_deps_mypy_test",
-    include_imports = True,
-    deps = [":fix_cc_deps"],
-)
-
-# Note that this Python script is intended to be run directly, and not through
-# Bazel. We have a rule for it so we can type check it.
-py_binary(
-    name = "forbid_llvm_googletest",
-    testonly = 1,
-    srcs = ["forbid_llvm_googletest.py"],
-    deps = [":scripts_utils"],
-)
-
-mypy_test(
-    name = "forbid_llvm_googletest_mypy_test",
-    include_imports = True,
-    deps = [":forbid_llvm_googletest"],
-)
-
-# Note that this Python script is intended to be run directly, and not through
-# Bazel. We have a rule for it so we can type check it.
-py_binary(
-    name = "run_bazel",
-    testonly = 1,
-    srcs = ["run_bazel.py"],
-    deps = [":scripts_utils"],
-)
-
-mypy_test(
-    name = "run_bazel_mypy_test",
-    include_imports = True,
-    deps = [":run_bazel"],
-)
-
-# Note that this Python script is intended to be run directly, and not through
-# Bazel. We have a rule for it so we can type check it.
-py_binary(
-    name = "run_buildifier",
-    testonly = 1,
-    srcs = ["run_buildifier.py"],
-    deps = [":scripts_utils"],
-)
-
-mypy_test(
-    name = "run_buildifier_mypy_test",
-    include_imports = True,
-    deps = [":run_buildifier"],
-)
-
-# Note that this Python script is intended to be run directly, and not through
-# Bazel. We have a rule for it so we can type check it.
-py_binary(
-    name = "run_buildozer",
-    testonly = 1,
-    srcs = ["run_buildozer.py"],
-    deps = [":scripts_utils"],
-)
-
-mypy_test(
-    name = "run_buildozer_mypy_test",
-    include_imports = True,
-    deps = [":run_buildozer"],
-)

scripts/create_compdb.py

@@ -29,7 +29,7 @@ import subprocess
 import sys
 from pathlib import Path
 
-import scripts_utils  # type: ignore
+import scripts_utils
 
 scripts_utils.chdir_repo_root()
 directory = Path.cwd()

scripts/fix_cc_deps.py

@@ -19,7 +19,7 @@ import subprocess
 from typing import Callable, Dict, List, NamedTuple, Set, Tuple
 from xml.etree import ElementTree
 
-import scripts_utils  # type: ignore
+import scripts_utils
 
 
 # Maps external repository names to a method translating bazel labels to file

scripts/forbid_llvm_googletest.py

@@ -20,7 +20,7 @@ SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
 import subprocess
 
-import scripts_utils  # type: ignore
+import scripts_utils
 
 _MESSAGE = """\
 Dependencies on @llvm-project//llvm:gtest are forbidden, but a dependency path

scripts/run_bazel.py

@@ -15,7 +15,7 @@ SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 import os
 import sys
 
-import scripts_utils  # type: ignore
+import scripts_utils
 
 
 def main() -> None:

scripts/run_buildifier.py

@@ -11,7 +11,7 @@ SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 import os
 import sys
 
-import scripts_utils  # type: ignore
+import scripts_utils
 
 
 def main() -> None:

scripts/run_buildozer.py

@@ -15,7 +15,7 @@ SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 import os
 import sys
 
-import scripts_utils  # type: ignore
+import scripts_utils
 
 
 def main() -> None: