Enable type checking

.github/workflows/ci.yml

@@ -17,7 +17,7 @@ jobs:
             uses: actions/setup-python@v1
             with:
                 # matches compat target in setup.py
-                python-version: '3.6'
+                python-version: '3.8'
         -   name: "Main Script"
             run: |
                 curl -L -O https://gitlab.tiker.net/inducer/ci-support/raw/main/prepare-and-run-flake8.sh
@@ -35,6 +35,19 @@ jobs:
                 curl -L -O https://gitlab.tiker.net/inducer/ci-support/raw/master/prepare-and-run-pylint.sh
                 . ./prepare-and-run-pylint.sh "$(basename $GITHUB_REPOSITORY)" examples/*.py test/test_*.py experiments/*.py
 
+    mypy:
+        name: Mypy
+        runs-on: ubuntu-latest
+        steps:
+        -   uses: actions/checkout@v2
+        -   name: "Main Script"
+            run: |
+                curl -L -O https://tiker.net/ci-support-v0
+                . ./ci-support-v0
+                build_py_project_in_conda_env
+                python -m pip install mypy
+                ./run-mypy.sh
+
     pytest3:
         name: Pytest Conda Py3
         runs-on: ubuntu-latest

.gitlab-ci.yml

@@ -112,6 +112,18 @@ Pylint:
   except:
   - tags
 
+Mypy:
+  script: |
+    curl -L -O https://tiker.net/ci-support-v0
+    . ./ci-support-v0
+    build_py_project_in_venv
+    python -m pip install mypy
+    ./run-mypy.sh
+  tags:
+  - python3
+  except:
+  - tags
+
 Downstream:
   parallel:
     matrix:

meshmode/mesh/processing.py

@@ -149,7 +149,8 @@ def _filter_mesh_groups(mesh, selected_elements, vertex_id_dtype):
     filtered_vertex_indices = [
             mesh.groups[i_old_grp].vertex_indices[
                     filtered_group_elements[i_new_grp], :]
-            for i_new_grp, i_old_grp in enumerate(new_group_to_old_group)]
+            for i_new_grp, i_old_grp in enumerate(new_group_to_old_group)
+            if mesh.groups[i_old_grp].vertex_indices is not None]
 
     if n_new_groups > 0:
         filtered_vertex_indices_flat = np.concatenate([indices.ravel() for indices
@@ -1287,14 +1288,14 @@ def map_mesh(mesh, f):  # noqa
 # {{{ affine map
 
 def affine_map(mesh,
-        A: Optional[Union[Real, np.ndarray]] = None,    # noqa: N803
-        b: Optional[Union[Real, np.ndarray]] = None):
+        A: Optional[Union[np.generic, np.ndarray]] = None,    # noqa: N803
+        b: Optional[Union[np.generic, np.ndarray]] = None):
     """Apply the affine map :math:`f(x) = A x + b` to the geometry of *mesh*."""
 
-    if isinstance(A, Real):
+    if A is not None and not isinstance(A, np.ndarray):
         A = np.diag([A] * mesh.ambient_dim)             # noqa: N806
 
-    if isinstance(b, Real):
+    if b is not None and not isinstance(b, np.ndarray):
         b = np.array([b] * mesh.ambient_dim)
 
     if A is None and b is None:

run-mypy.sh

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+python -m mypy --show-error-codes meshmode # examples test

setup.cfg

@@ -8,3 +8,68 @@ docstring-quotes = """
 multiline-quotes = """
 
 # enable-flake8-bugbear
+
+[mypy]
+python_version = 3.8
+warn_unused_ignores = True
+
+exclude = (?x)(
+        meshmode/discretization/.*
+        | meshmode/mesh/__init__.py
+        | meshmode/mesh/generation\.py
+        | meshmode/mesh/visualization\.py
+        | meshmode/mesh/refinement/.*
+        | meshmode/interop/.*
+        | meshmode/dof_array\.py
+        )
+
+[mypy-pyvisfile.*]
+ignore_missing_imports = True
+
+[mypy-matplotlib.*]
+ignore_missing_imports = True
+
+[mypy-mpl_toolkits.*]
+ignore_missing_imports = True
+
+[mypy-firedrake.*]
+ignore_missing_imports = True
+
+[mypy-pyop2.*]
+ignore_missing_imports = True
+
+[mypy-finat.*]
+ignore_missing_imports = True
+
+[mypy-FIAT.*]
+ignore_missing_imports = True
+
+[mypy-loopy.*]
+ignore_missing_imports = True
+
+[mypy-gmsh_interop.*]
+ignore_missing_imports = True
+
+[mypy-scipy.*]
+ignore_missing_imports = True
+
+[mypy-pymetis.*]
+ignore_missing_imports = True
+
+[mypy-pymbolic.*]
+ignore_missing_imports = True
+
+[mypy-recursivenodes.*]
+ignore_missing_imports = True
+
+[mypy-mayavi.*]
+ignore_missing_imports = True
+
+[mypy-h5py.*]
+ignore_missing_imports = True
+
+[mypy-oct2py.*]
+ignore_missing_imports = True
+
+[mypy-pyopencl.*]
+ignore_missing_imports = True

setup.py

@@ -27,9 +27,6 @@ def main():
               "Natural Language :: English",
               "Programming Language :: Python",
               "Programming Language :: Python :: 3",
-              "Programming Language :: Python :: 3.6",
-              "Programming Language :: Python :: 3.7",
-              "Programming Language :: Python :: 3.8",
               "Topic :: Scientific/Engineering",
               "Topic :: Scientific/Engineering :: Information Analysis",
               "Topic :: Scientific/Engineering :: Mathematics",
@@ -39,7 +36,7 @@ def main():
               ],
 
           packages=find_packages(),
-          python_requires="~=3.6",
+          python_requires="~=3.8",
           install_requires=[
               "numpy",
               "modepy>=2020.2",