Add explicit signatures for pyplot.{polar,savefig,set_loglevel} (matplotlib#30200)

* Create tests

(cherry picked from commit 608b51f)

* Update test_pyplot.py to include type on signature

(cherry picked from commit 4ea0ff8)

* Update polar and set_loglevel signature on pyplot.py

(cherry picked from commit 41b701b)

* Update savefig signature on pyplot.py

(cherry picked from commit b863ba2)

* Add type hint on polar and set_loglevel on pyplot.py. Correct polar content

(cherry picked from commit 92dc045)

* Format with ruff

(cherry picked from commit 64e7921)

* Revert polar on pyplot.py and remove corresponding test

* Remove extra work when stub file doesn't exists

Co-authored-by: Elliott Sales de Andrade <quantum.analyst@gmail.com>

* Replace assert_signatures_identical (check return_annotation and full parameters) with assert_same_signature (only check len(parameters), names and kinds)

* Remove unused import

* Renaming assert_signature arguments

* Correct typo and ruff error

---------

Co-authored-by: Corenthin ZOZOR <corenthin.zozor@gmail.com>
Co-authored-by: Elliott Sales de Andrade <quantum.analyst@gmail.com>

Author: 3 people

lib/matplotlib/pyplot.py

@@ -50,7 +50,7 @@
 import sys
 import threading
 import time
-from typing import TYPE_CHECKING, cast, overload
+from typing import IO, TYPE_CHECKING, cast, overload
 
 from cycler import cycler  # noqa: F401
 import matplotlib
@@ -338,8 +338,8 @@ def uninstall_repl_displayhook() -> None:
 
 # Ensure this appears in the pyplot docs.
 @_copy_docstring_and_deprecators(matplotlib.set_loglevel)
-def set_loglevel(*args, **kwargs) -> None:
-    return matplotlib.set_loglevel(*args, **kwargs)
+def set_loglevel(level: str) -> None:
+    return matplotlib.set_loglevel(level)
 
 
 @_copy_docstring_and_deprecators(Artist.findobj)
@@ -1259,11 +1259,11 @@ def draw() -> None:
 
 
 @_copy_docstring_and_deprecators(Figure.savefig)
-def savefig(*args, **kwargs) -> None:
+def savefig(fname: str | os.PathLike | IO, **kwargs) -> None:
     fig = gcf()
     # savefig default implementation has no return, so mypy is unhappy
     # presumably this is here because subclasses can return?
-    res = fig.savefig(*args, **kwargs)  # type: ignore[func-returns-value]
+    res = fig.savefig(fname, **kwargs)  # type: ignore[func-returns-value]
     fig.canvas.draw_idle()  # Need this if 'transparent=True', to reset colors.
     return res
 

lib/matplotlib/tests/test_pyplot.py

@@ -1,4 +1,5 @@
 import difflib
+import inspect
 
 import numpy as np
 import sys
@@ -484,3 +485,26 @@ def test_matshow():
 
     # Smoke test that matshow does not ask for a new figsize on the existing figure
     plt.matshow(arr, fignum=fig.number)
+
+
+def assert_same_signature(func1, func2):
+    """
+    Assert that `func1` and `func2` have the same arguments,
+    i.e. same parameter count, names and kinds.
+
+    :param func1: First function to check
+    :param func2: Second function to check
+    """
+    params1 = inspect.signature(func1).parameters
+    params2 = inspect.signature(func2).parameters
+
+    assert len(params1) == len(params2)
+    assert all([
+        params1[p].name == params2[p].name and
+        params1[p].kind == params2[p].kind
+        for p in params1
+    ])
+
+
+def test_setloglevel_signature():
+    assert_same_signature(plt.set_loglevel, mpl.set_loglevel)