From a85790ee6f4dbe738119f012767bd57ec843cf4d Mon Sep 17 00:00:00 2001
From: Ronny Pfannschmidt <opensource@ronnypfannschmidt.de>
Date: Sat, 7 Aug 2021 22:22:13 +0200
Subject: [PATCH] begin mypy usage - addresses part of #501

---
 .pre-commit-config.yaml        |  9 ++++++++-
 mypy.ini                       |  9 +++++++++
 src/setuptools_scm/__main__.py |  2 +-
 src/setuptools_scm/config.py   |  2 +-
 src/setuptools_scm/utils.py    | 13 +++++++------
 5 files changed, 26 insertions(+), 9 deletions(-)
 create mode 100644 mypy.ini

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 60466c99..c847bb27 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -21,7 +21,7 @@ repos:
     hooks:
     -   id: flake8
 -   repo: https://github.com/asottile/pyupgrade
-    rev: v2.23.1
+    rev: v2.23.3
     hooks:
     - id: pyupgrade
       args: [--py36-plus]
@@ -29,3 +29,10 @@ repos:
     rev: v1.17.0
     hooks:
     -   id: setup-cfg-fmt
+-   repo: https://github.com/pre-commit/mirrors-mypy
+    rev: 'v0.910'
+    hooks:
+    -   id: mypy
+        additional_dependencies:
+            - types-setuptools
+            - tokenize-rt==3.2.0
diff --git a/mypy.ini b/mypy.ini
new file mode 100644
index 00000000..66723288
--- /dev/null
+++ b/mypy.ini
@@ -0,0 +1,9 @@
+[mypy]
+python_version = 3.6
+warn_return_any = True
+warn_unused_configs = True
+mypy_path = $MYPY_CONFIG_FILE_DIR/src
+
+[mypy-setuptools_scm.*]
+# disabled as it will take a bit
+# disallow_untyped_defs = True
diff --git a/src/setuptools_scm/__main__.py b/src/setuptools_scm/__main__.py
index ead0bc1e..f3377b05 100644
--- a/src/setuptools_scm/__main__.py
+++ b/src/setuptools_scm/__main__.py
@@ -4,7 +4,7 @@
 from setuptools_scm.integration import find_files
 
 
-def main():
+def main() -> None:
     print("Guessed Version", get_version())
     if "ls" in sys.argv:
         for fname in find_files("."):
diff --git a/src/setuptools_scm/config.py b/src/setuptools_scm/config.py
index 7ecb1c6d..473402e8 100644
--- a/src/setuptools_scm/config.py
+++ b/src/setuptools_scm/config.py
@@ -8,7 +8,7 @@
 except ImportError:
     import pkg_resources
 
-    Version = pkg_resources.packaging.version.Version
+    Version = pkg_resources.packaging.version.Version  # type: ignore
 
 
 from .utils import trace
diff --git a/src/setuptools_scm/utils.py b/src/setuptools_scm/utils.py
index c033dc33..7ea540d8 100644
--- a/src/setuptools_scm/utils.py
+++ b/src/setuptools_scm/utils.py
@@ -9,7 +9,7 @@
 import sys
 import traceback
 import warnings
-
+from typing import Optional
 
 DEBUG = bool(os.environ.get("SETUPTOOLS_SCM_DEBUG"))
 IS_WINDOWS = platform.system() == "Windows"
@@ -36,14 +36,15 @@ def no_git_env(env):
     }
 
 
-def trace(*k):
+def trace(*k) -> None:
     if DEBUG:
         print(*k)
         sys.stdout.flush()
 
 
-def trace_exception():
-    DEBUG and traceback.print_exc()
+def trace_exception() -> None:
+    if DEBUG:
+        traceback.print_exc()
 
 
 def ensure_stripped_str(str_or_bytes):
@@ -144,12 +145,12 @@ def require_command(name):
 
 
 try:
-    from importlib.metadata import entry_points
+    from importlib.metadata import entry_points  # type: ignore
 except ImportError:
     from pkg_resources import iter_entry_points
 else:
 
-    def iter_entry_points(group, name=None):
+    def iter_entry_points(group: str, name: Optional[str] = None):
         eps = entry_points()[group]
         if name is None:
             return iter(eps)