add mypy to CI

7 files changed, 27 insertions, 6 deletions

diff --git a/.gitignore b/.gitignore
index 10fe6e96..11a657c4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -67,3 +67,6 @@ pip-selfcheck.json
 # Python3 Venv Files
 venv/
 pyvenv.cfg
+
+# mypy
+.mypy_cache
\ No newline at end of file
diff --git a/.travis.yml b/.travis.yml
index e1205586..9c711d42 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,6 +8,8 @@ matrix:
       env: TOXENV=isort-check
     - python: 3.7
       env: TOXENV=lint
+    - python: 3.7
+      env: TOXENV=mypy
     - python: 3.4
       env: TOXENV=py34
     - python: 3.5
diff --git a/isort/main.py b/isort/main.py
index a24864fa..e4bc9107 100644
--- a/isort/main.py
+++ b/isort/main.py
@@ -23,6 +23,7 @@ import glob
 import os
 import re
 import sys
+from typing import Any, List  # noqa: F401
 
 import setuptools
 
@@ -123,7 +124,7 @@ class ISortCommand(setuptools.Command):
     """
 
     description = "Run isort on modules registered in setuptools"
-    user_options = []
+    user_options = []  # type: List[Any]
 
     def initialize_options(self):
         default_settings = default.copy()
diff --git a/isort/settings.py b/isort/settings.py
index 3603a2f2..5a21fa30 100644
--- a/isort/settings.py
+++ b/isort/settings.py
@@ -38,7 +38,7 @@ from .utils import difference, union
 try:
     import toml
 except ImportError:
-    toml = False
+    toml = None
 
 try:
     import appdirs
@@ -54,9 +54,9 @@ safety_exclude_re = re.compile(
     r"/(\.eggs|\.git|\.hg|\.mypy_cache|\.nox|\.tox|\.venv|_build|buck-out|build|dist|lib/python[0-9].[0-9]+)/"
 )
 
-WrapModes = ('GRID', 'VERTICAL', 'HANGING_INDENT', 'VERTICAL_HANGING_INDENT', 'VERTICAL_GRID', 'VERTICAL_GRID_GROUPED',
-             'VERTICAL_GRID_GROUPED_NO_COMMA', 'NOQA')
-WrapModes = namedtuple('WrapModes', WrapModes)(*range(len(WrapModes)))
+_wrap_mode_strings = ('GRID', 'VERTICAL', 'HANGING_INDENT', 'VERTICAL_HANGING_INDENT', 'VERTICAL_GRID', 'VERTICAL_GRID_GROUPED',
+                      'VERTICAL_GRID_GROUPED_NO_COMMA', 'NOQA')
+WrapModes = namedtuple('WrapModes', _wrap_mode_strings)(*range(len(_wrap_mode_strings)))
 
 # Note that none of these lists must be complete as they are simply fallbacks for when included auto-detection fails.
 default = {'force_to_top': [],
@@ -115,7 +115,7 @@ default = {'force_to_top': [],
                                       'zipimport', 'zlib'],
            'known_third_party': ['google.appengine.api'],
            'known_first_party': [],
-           'multi_line_output': WrapModes.GRID,
+           'multi_line_output': WrapModes.GRID,  # type: ignore
            'forced_separate': [],
            'indent': ' ' * 4,
            'comment_prefix': '  #',
diff --git a/mypy-requirements.txt b/mypy-requirements.txt
new file mode 100644
index 00000000..8006c4ad
--- /dev/null
+++ b/mypy-requirements.txt
@@ -0,0 +1,2 @@
+mypy==0.670
+typing==3.6.6
\ No newline at end of file
diff --git a/setup.cfg b/setup.cfg
index c39295eb..fcf1fbad 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -10,3 +10,8 @@ ignore =
 
 [metadata]
 license_file = LICENSE
+
+[mypy]
+follow_imports = silent
+ignore_missing_imports = True
+strict_optional = False
\ No newline at end of file
diff --git a/tox.ini b/tox.ini
index cb36b189..3e2cc62d 100644
--- a/tox.ini
+++ b/tox.ini
@@ -3,6 +3,7 @@ minversion = 2.4
 envlist =
     isort-check,
     lint,
+    mypy,
     py{34,35,36,37,py3}
 
 [testenv]
@@ -22,3 +23,10 @@ commands = python setup.py isort
 deps = flake8==3.5.0
 commands = flake8
 skip_install = True
+
+[testenv:mypy]
+basepython = python3
+deps = -r{toxinidir}/mypy-requirements.txt
+commands =
+    mypy .
+skip_install = True