Add minimal typecheck infrastructure to CI (has2k1#644)

* add mypy.ini, but ignore errors at first

* type hint labels

* type hint options, exceptions

Also fix an import error in options.
It attempted a relative import beyond the top level package.

* Add typecheck job to CI

* resolve feedback

.github/workflows/testing.yml

@@ -84,6 +84,40 @@ jobs:
  shell: bash -l {0}
  run: make lint
 
+
+ # Typecheck
+ typecheck:
+ runs-on: ubuntu-latest
+
+ # We want to run on external PRs, but not on our own internal PRs as they'll be run
+ # by the push to the branch.
+ if: github.event_name == 'push' || github.event.pull_request.head.repo.full_name != github.repository
+
+ strategy:
+ matrix:
+ python-version: [3.8]
+ steps:
+ - name: Checkout Code
+ uses: actions/checkout@v3
+
+ - name: Setup Python
+ uses: actions/setup-python@v3
+ with:
+ python-version: ${{ matrix.python-version }}
+
+ - name: Install Packages
+ shell: bash -l {0}
+ run: pip install mypy
+
+ - name: Environment Information
+ shell: bash -l {0}
+ run: pip list
+
+ - name: Run Tests
+ shell: bash -l {0}
+ run: make typecheck
+
+
  # Documentation
  documentation:
  runs-on: ubuntu-latest

Makefile

@@ -39,6 +39,9 @@ clean-test:
 lint:
  flake8 plotnine
 
+typecheck:
+ mypy plotnine
+
 test: clean-test
  export MATPLOTLIB_BACKEND=agg
  pytest

mypy.ini

@@ -0,0 +1,47 @@
+# Mypy configuration file
+# See docs: https://mypy.readthedocs.io/en/stable/config_file.html
+[mypy]
+
+# Specifies the Python version used to parse and check the target program.
+# We're using the oldest supported python version. Mypy will warn us if we use
+# features or parts of the stdlib that are too new.
+python_version = 3.8
+
+# Set some rather strict defaults, but also globally deactivate all errors
+# and then activate the typecheck only for certain modules.
+# The set of typechcecked modules can be incrementally expanded until everything
+# is correctly typed.
+
+# Shows a warning when returning a value with type Any from a function declared with a non- Any return type.
+warn_return_any = True
+
+# Warns about per-module sections in the config file that do not match any files processed when invoking mypy.
+# Has no effect in incremental mode
+warn_unused_configs = True
+
+# Disallows defining functions without type annotations or with incomplete type annotations.
+# Once a module is fully typed, this should be activated to avoid regressions.
+disallow_untyped_defs = True
+
+# Disallows usage of generic types that do not specify explicit type parameters.
+disallow_any_generics = True
+
+# Allows variables to be redefined with an arbitrary type, as long as the redefinition is in the same block and nesting level as the original definition.
+# The original variable must have been used before redefinition.
+allow_redefinition = True
+
+# Shows a warning when encountering any code inferred to be unreachable or redundant after performing type analysis.
+warn_unreachable = True
+
+# Ignores all non-fatal errors.
+ignore_errors = True
+
+# per module options
+[mypy-plotnine.labels]
+ignore_errors = False
+
+[mypy-plotnine.options]
+ignore_errors = False
+
+[mypy-plotnine.exceptions]
+ignore_errors = False

plotnine/exceptions.py

@@ -1,10 +1,13 @@
+from __future__ import annotations
 from textwrap import dedent
 import warnings
 
 
 # Show the warnings on one line, leaving out any code makes the
 # message clear
-def warning_format(message, category, filename, lineno, file=None, line=None):
+def warning_format( # type: ignore
+ message, category, filename, lineno, line=None
+):
  """
  Format for plotnine warnings
  """
@@ -20,11 +23,11 @@ class PlotnineError(Exception):
  Exception for ggplot errors
  """
 
- def __init__(self, *args):
+ def __init__(self, *args: str) -> None:
  args = [dedent(arg) for arg in args]
  self.message = " ".join(args)
 
- def __str__(self):
+ def __str__(self) -> str:
  """
  Error Message
  """

plotnine/labels.py

@@ -1,8 +1,13 @@
+from __future__ import annotations
 from copy import deepcopy
 
 from .mapping.aes import rename_aesthetics, SCALED_AESTHETICS
 from .exceptions import PlotnineError
 
+import typing
+if typing.TYPE_CHECKING:
+ import plotnine as p9
+
 __all__ = ['xlab', 'ylab', 'labs', 'ggtitle']
 VALID_LABELS = SCALED_AESTHETICS | {'caption', 'title'}
 
@@ -17,17 +22,17 @@ class labs:
  Aesthetics (with scales) to be renamed. You can also
  set the ``title`` and ``caption``.
  """
- labels = {}
+ labels: dict[str, str] = {}
 
- def __init__(self, **kwargs):
+ def __init__(self, **kwargs: str) -> None:
  unknown = kwargs.keys() - VALID_LABELS
  if unknown:
  raise PlotnineError(
  f"Cannot deal with these labels: {unknown}"
  )
  self.labels = rename_aesthetics(kwargs)
 
- def __radd__(self, gg, inplace=False):
+ def __radd__(self, gg: p9.ggplot, inplace: bool = False) -> p9.ggplot:
  """
  Add labels to ggplot object
  """
@@ -46,7 +51,7 @@ class xlab(labs):
  x-axis label
  """
 
- def __init__(self, xlab):
+ def __init__(self, xlab: str) -> None:
  if xlab is None:
  raise PlotnineError(
  "Arguments to xlab cannot be None")
@@ -63,7 +68,7 @@ class ylab(labs):
  y-axis label
  """
 
- def __init__(self, ylab):
+ def __init__(self, ylab: str) -> None:
  if ylab is None:
  raise PlotnineError(
  "Arguments to ylab cannot be None")
@@ -80,7 +85,7 @@ class ggtitle(labs):
  Plot title
  """
 
- def __init__(self, title):
+ def __init__(self, title: str) -> None:
  if title is None:
  raise PlotnineError(
  "Arguments to ggtitle cannot be None")

plotnine/options.py

@@ -1,3 +1,5 @@
+from typing import Any
+
 #: Development flag, e.g. set to ``True`` to prevent
 #: the queuing up of figures when errors happen.
 close_all_figures = False
@@ -28,7 +30,7 @@
 }
 
 
-def get_option(name):
+def get_option(name: str) -> Any:
  """
  Get package option
 
@@ -40,13 +42,13 @@ def get_option(name):
  d = globals()
 
  if name in {'get_option', 'set_option'} or name not in d:
- from ..exceptions import PlotnineError
+ from .exceptions import PlotnineError
  raise PlotnineError(f"Unknown option {name}")
 
  return d[name]
 
 
-def set_option(name, value):
+def set_option(name: str, value: Any) -> Any:
  """
  Set package option
 
@@ -65,7 +67,7 @@ def set_option(name, value):
  d = globals()
 
  if name in {'get_option', 'set_option'} or name not in d:
- from ..exceptions import PlotnineError
+ from .exceptions import PlotnineError
  raise PlotnineError(f"Unknown option {name}")
 
  old = d[name]