[gobject-introspection: 2/3] Add basic mypy support

[Christoph Reiter <creiter src gnome org>]

commit 1b3237ba383ba644628defcfde443e9a4e5af69c
Author: Christoph Reiter <reiter christoph gmail com>
Date:   Sat Nov 7 11:00:30 2020 +0100

    Add basic mypy support
    
    Silence some errors, run mypy in CI
    
    Adding annotations to functions/classes will make mypy check them.

 .gitignore                     | 3 +++
 .gitlab-ci.yml                 | 3 ++-
 .gitlab-ci/test-msys2-meson.sh | 3 ++-
 giscanner/__init__.py          | 2 +-
 giscanner/annotationparser.py  | 3 ++-
 giscanner/utils.py             | 4 ++--
 mypy.ini                       | 3 +++
 7 files changed, 15 insertions(+), 6 deletions(-)
---
diff --git a/.gitignore b/.gitignore
index 2f1be7230..1e9e54eb4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -155,3 +155,6 @@ htmlcov*
 
 #emacs
 .dir-locals.el
+
+
+.mypy_cache
\ No newline at end of file
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index e9e79b979..2d79aa1da 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -56,8 +56,9 @@ fedora-x86_64-meson:
     - cd ..
     - mkdir -p public
     - mv _build/docs/reference/html/ public/girepository/
-    - python3 -m pip install --user flake8
+    - python3 -m pip install --user flake8 mypy
     - python3 -m flake8 --count
+    - python3 -m mypy .
   except:
     - tags
   artifacts:
diff --git a/.gitlab-ci/test-msys2-meson.sh b/.gitlab-ci/test-msys2-meson.sh
index 9f145e5b5..81a82437d 100644
--- a/.gitlab-ci/test-msys2-meson.sh
+++ b/.gitlab-ci/test-msys2-meson.sh
@@ -31,7 +31,7 @@ pacman --noconfirm -S --needed \
 export CCACHE_BASEDIR="${CI_PROJECT_DIR}"
 export CCACHE_DIR="${CCACHE_BASEDIR}/_ccache"
 
-pip3 install --upgrade --user meson==0.50.1 flake8
+pip3 install --upgrade --user meson==0.50.1 flake8 mypy
 export PATH="$HOME/.local/bin:$PATH"
 
 export CFLAGS="-Werror"
@@ -43,3 +43,4 @@ meson test --print-errorlogs --suite=gobject-introspection --no-suite=glib
 cd ..
 
 python3 -m flake8 --count
+python3 -m mypy .
\ No newline at end of file
diff --git a/giscanner/__init__.py b/giscanner/__init__.py
index 79c537e8f..7c2f365ab 100644
--- a/giscanner/__init__.py
+++ b/giscanner/__init__.py
@@ -20,7 +20,7 @@
 import os
 builddir = os.environ.get('UNINSTALLED_INTROSPECTION_BUILDDIR')
 if builddir is not None:
-    __path__.append(os.path.join(builddir, 'giscanner'))
+    __path__.append(os.path.join(builddir, 'giscanner'))  # type: ignore  # mypy issue #1422
 try:
     from ._version import __version__
 except ImportError:
diff --git a/giscanner/annotationparser.py b/giscanner/annotationparser.py
index f8257206f..267542f95 100644
--- a/giscanner/annotationparser.py
+++ b/giscanner/annotationparser.py
@@ -110,6 +110,7 @@ import os
 import re
 import operator
 
+from typing import Tuple
 from operator import ne, gt, lt
 from collections import namedtuple, Counter, OrderedDict
 
@@ -575,7 +576,7 @@ class GtkDocAnnotatable(object):
     #: A :class:`tuple` of annotation name constants that are valid for this object. Annotation
     #: names not in this :class:`tuple` will be reported as *unknown* by :func:`validate`. The
     #: :attr:`valid_annotations` class attribute should be overridden by subclasses.
-    valid_annotations = ()
+    valid_annotations = ()  # type: Tuple[str,...]
 
     def __init__(self, position=None):
         #: A :class:`giscanner.message.Position` instance specifying the location of the
diff --git a/giscanner/utils.py b/giscanner/utils.py
index d9938fc7e..9007db133 100644
--- a/giscanner/utils.py
+++ b/giscanner/utils.py
@@ -346,5 +346,5 @@ def get_msvcr_overwrite():
 
 
 import distutils.cygwinccompiler
-orig_get_msvcr = distutils.cygwinccompiler.get_msvcr
-distutils.cygwinccompiler.get_msvcr = get_msvcr_overwrite
+orig_get_msvcr = distutils.cygwinccompiler.get_msvcr  # type: ignore
+distutils.cygwinccompiler.get_msvcr = get_msvcr_overwrite  # type: ignore
diff --git a/mypy.ini b/mypy.ini
new file mode 100644
index 000000000..e69a623d7
--- /dev/null
+++ b/mypy.ini
@@ -0,0 +1,3 @@
+[mypy]
+ignore_missing_imports = True
+python_version = 3.5
\ No newline at end of file