feat: Add typehints to pyhf.tensor (#1940)

* Add typehints to the NumPy backend.
* Add .coveragerc file with configuration to ignore pyhf/typing.py.
  - ref: https://coverage.readthedocs.io/en/6.4.3/excluding.html#advanced-exclusion
  - Reverts part of PR #1942.
* Ignore pyhf/typing.py in Codecov.

.coveragerc

@@ -0,0 +1,3 @@
+[report]
+omit =
+    src/pyhf/typing.py

.pre-commit-config.yaml

@@ -61,10 +61,18 @@ repos:
 
 -   repo: https://github.com/pre-commit/mirrors-mypy
     rev: v0.971
+    # check the oldest and newest supported Pythons
     hooks:
-      - id: mypy
+      - &mypy
+        id: mypy
+        name: mypy with Python 3.7
         files: src
-        args: []
+        additional_dependencies:
+          ['numpy', 'types-tqdm', 'click', 'types-jsonpatch', 'types-pyyaml', 'types-jsonschema', 'importlib_metadata', 'packaging']
+        args: ["--python-version=3.7"]
+      - <<: *mypy
+        name: mypy with Python 3.10
+        args: ["--python-version=3.10"]
 
 -   repo: https://github.com/nbQA-dev/nbQA
     rev: 1.4.0

codecov.yml

@@ -3,3 +3,6 @@ coverage:
     project:
       default:
         threshold: 0.2%
+
+ignore:
+  - "**/typing.py"

pyproject.toml

@@ -108,24 +108,19 @@ warn_unreachable = true
 
 [[tool.mypy.overrides]]
 module = [
-  'matplotlib.*',
   'jax.*',
-  'click.*',
-  'click_completion.*',
-  'numpy.*',
+  'matplotlib.*',
   'scipy.*',
-  'jsonpatch.*',
+  'tensorflow.*',
+  'tensorflow_probability.*',
+  'torch.*',
   'uproot.*',
-  'yaml.*',
-  'jsonschema.*',
-  'tqdm.*',
 ]
 ignore_missing_imports = true
 
 [[tool.mypy.overrides]]
 module = [
   'pyhf',
-  'pyhf.tensor.*',
   'pyhf.optimize.*',
   'pyhf.contrib.*',
   'pyhf.infer.*',
@@ -146,5 +141,11 @@ module = [
   'pyhf.pdf',
   'pyhf.simplemodels',
   'pyhf.probability',
+  'pyhf.tensor.common.*',
+  'pyhf.tensor.manager.*',
+  'pyhf.tensor',
+  'pyhf.tensor.jax_backend.*',
+  'pyhf.tensor.tensorflow_backend.*',
+  'pyhf.tensor.pytorch_backend.*',
 ]
 ignore_errors = true

src/pyhf/readxml.py

@@ -438,7 +438,7 @@ def parse(
     mounts = mounts or []
     toplvl = ET.parse(configfile)
     inputs = tqdm.tqdm(
-        [x.text for x in toplvl.findall('Input')],
+        [x.text for x in toplvl.findall('Input') if x.text],
         unit='channel',
         disable=not (track_progress),
     )