Revamp linting processes

.github/workflows/python-linters.yml

@@ -20,9 +20,6 @@ jobs:
         env:
         - TOXENV: docs
         - TOXENV: lint
-        - TOXENV: lint-py2
-          PYTHON_VERSION: 2.7
-        - TOXENV: mypy
         - TOXENV: packaging
     steps:
     - uses: actions/checkout@master

.pre-commit-config.yaml

@@ -0,0 +1,38 @@
+exclude: 'src/pip/_vendor/'
+
+repos:
+- repo: https://github.com/pre-commit/pre-commit-hooks
+  rev: v2.3.0
+  hooks:
+    # - id: check-builtin-literals  # TODO: enable when fixed.
+    - id: check-added-large-files
+    - id: check-case-conflict
+    - id: check-toml
+    - id: check-yaml
+    - id: debug-statements
+    # - id: end-of-file-fixer  # TODO: enable when fixed.
+    - id: flake8
+      exclude: tests/data
+    - id: forbid-new-submodules
+    # - id: trailing-whitespace  # TODO: enable when fixed.
+    #   exclude: .patch
+
+# TODO: enable when fixed.
+# - repo: https://github.com/timothycrosley/isort
+#   rev: 4.3.21
+#   hooks:
+#     - id: isort
+#       files: \.py$
+
+- repo: https://github.com/pre-commit/mirrors-mypy
+  rev: v0.720
+  hooks:
+    - id: mypy
+      exclude: docs|tests
+
+- repo: https://github.com/pre-commit/pygrep-hooks
+  rev: v1.4.1
+  hooks:
+    - id: python-no-log-warn
+    - id: python-no-eval
+    # - id: rst-backticks  # TODO: enable when fixed.

.travis.yml

@@ -17,9 +17,6 @@ jobs:
     - stage: primary
       env: TOXENV=docs
     - env: TOXENV=lint
-    - env: TOXENV=lint-py2
-      python: 2.7
-    - env: TOXENV=mypy
     - env: TOXENV=packaging
     # Latest CPython
     - env: GROUP=1

docs/html/development/getting-started.rst

@@ -76,26 +76,6 @@ To use linters locally, run:
 .. code-block:: console
 
     $ tox -e lint
-    $ tox -e lint-py2
-
-The above commands run the linters on Python 3 followed by Python 2.
-
-.. note::
-
-    Do not silence errors from flake8 with ``# noqa`` comments or otherwise.
-
-Running mypy
-------------
-
-pip uses :pypi:`mypy` to run static type analysis, which helps catch certain
-kinds of bugs. The codebase uses `PEP 484 type-comments`_ due to compatibility
-requirements with Python 2.7.
-
-To run the ``mypy`` type checker, run:
-
-.. code-block:: console
-
-    $ tox -e mypy
 
 Building Documentation
 ----------------------

tools/travis/run.sh

@@ -1,9 +1,8 @@
 #!/bin/bash
 set -e
 
-# Short circuit tests and linting jobs if there are no code changes involved.
-if [[ $TOXENV != docs ]] && [[ $TOXENV != lint-py2 ]] && [[ $TOXENV != lint ]]; then
-    # Keep lint and lint-py2, for docs/conf.py
+# Short circuit test runs if there are no code changes involved.
+if ! [[ $TOXENV ~= ^(docs|lint|packaging)$ ]]; then
     if [[ "$TRAVIS_PULL_REQUEST" == "false" ]]
     then
         echo "This is not a PR -- will do a complete build."
@@ -18,7 +17,7 @@ if [[ $TOXENV != docs ]] && [[ $TOXENV != lint-py2 ]] && [[ $TOXENV != lint ]];
         echo "$changes"
         if ! echo "$changes" | grep -qvE '(\.rst$)|(^docs)|(^news)|(^\.github)'
         then
-            echo "Only Documentation was updated -- skipping build."
+            echo "Code was not changed -- skipping build."
             exit
         fi
     fi

tox.ini

@@ -1,7 +1,7 @@
 [tox]
 minversion = 3.4.0
 envlist =
-    docs, packaging, mypy, lint, lint-py2,
+    docs, packaging, lint,
     py27, py35, py36, py37, py38, pypy, pypy3
 
 [helpers]
@@ -61,22 +61,3 @@ commands_pre =
 commands =
     flake8
     isort --check-only --diff
-
-[testenv:lint-py2]
-skip_install = True
-basepython = python2
-deps = {[lint]deps}
-commands_pre =
-# No need to flake8 docs, tools & tasks in py2
-commands =
-    flake8 src tests
-    isort --check-only --diff
-
-[testenv:mypy]
-skip_install = True
-basepython = python3
-deps = -r{toxinidir}/tools/requirements/mypy.txt
-commands_pre =
-commands =
-    mypy src
-    mypy src -2