Drop python 3.9 support (PlasmaPy#2501)

* Drop support for Python 3.9

* Add strict=False to zip calls

* Replace typing.Union with | operator

* Add changelog entry

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Enable type union syntax in annotations

* Apply UP006 & UP007 rules from ruff for annotations

* Upgrade more type hints

* Revert "Upgrade more type hints"

This reverts commit 9313eb1.

* Revert "Apply UP006 & UP007 rules from ruff for annotations"

This reverts commit d81b066.

* Revert "Enable type union syntax in annotations"

This reverts commit 7c0cbe4.

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

.github/workflows/tests.yml

@@ -39,11 +39,6 @@ jobs:
           python: '3.10'
           toxenv: py310-all
 
-        - name: Python 3.9 (Windows), minimal dependencies
-          os: windows-latest
-          python: 3.9
-          toxenv: py39-all-minimal
-
         - name: mypy
           os: ubuntu-latest
           python: '3.12'

README.md

@@ -95,7 +95,7 @@ very welcome!
 
 ## Installation
 
-PlasmaPy requires Python 3.9 or newer. If you do not have Python
+PlasmaPy requires Python 3.10 or newer. If you do not have Python
 installed already, here are the instructions to [download and install
 Python].
 
@@ -104,14 +104,14 @@ To install PlasmaPy on macOS or Linux, open a terminal and run:
 python -m pip install plasmapy
 ```
 On some systems, it might be necessary to specify the Python version
-number, for example by using `python3` or `python3.11` instead of
+number, for example by using `python3` or `python3.12` instead of
 `python`.
 
 To install PlasmaPy on Windows, open a terminal and run
 ```Shell
-py -3.11 -m pip install plasmapy
+py -3.12 -m pip install plasmapy
 ```
-The `3.11` may be replaced by any version of Python that is supported by
+The `3.12` may be replaced by any version of Python that is supported by
 PlasmaPy.
 
 If you have [installed Conda], then you can also install PlasmaPy into

changelog/2501.breaking.rst

@@ -0,0 +1 @@
+Changed the minimum required version of Python from 3.9 to 3.10.

docs/_global_substitutions.py

@@ -83,8 +83,8 @@
     "keyword-only": r":term:`keyword-only`\ ",
     "lite-function": r":term:`lite-function`\ ",
     "lite-functions": r":term:`lite-functions`\ ",
-    "maxpython": "3.11",
-    "minpython": "3.9",
+    "maxpython": "3.12",
+    "minpython": "3.10",
     "Open a terminal": r":ref:`Open a terminal <opening-a-terminal>`\ ",
     "parameter": r":term:`parameter`\ ",
     "parameters": r":term:`parameters <parameter>`\ ",

docs/notebooks/analysis/fit_functions.ipynb

@@ -291,7 +291,7 @@
     "plt.legend(fontsize=14, loc=\"upper left\")\n",
     "\n",
     "txt = f\"$f(x) = {explin.latex_str}$\\n$r^2 = {explin.rsq:.3f}$\\n\"\n",
-    "for name, param, err in zip(explin.param_names, explin.params, explin.param_errors):\n",
+    "for name, param, err in zip(explin.param_names, explin.params, explin.param_errors, strict=False):\n",
     "    txt += f\"{name} = {param:.3f} $\\\\pm$ {err:.3f}\\n\"\n",
     "txt_loc = [-13.0, ax.get_ylim()[1]]\n",
     "txt_loc = ax.transAxes.inverted().transform(ax.transData.transform(txt_loc))\n",

docs/notebooks/analysis/swept_langmuir/find_floating_potential.ipynb

@@ -308,7 +308,7 @@
     "axs[0].legend(fontsize=12)\n",
     "\n",
     "# zoom on fit\n",
-    "for ii, label, rtn in zip([1, 2], [\"Exponential\", \"Linear\"], [results, results_lin]):\n",
+    "for ii, label, rtn in zip([1, 2], [\"Exponential\", \"Linear\"], [results, results_lin], strict=False):\n",
     "    vf = rtn[0]\n",
     "    extras = rtn[1]\n",
     "\n",

docs/notebooks/particles/ace.ipynb

@@ -428,7 +428,7 @@
    "source": [
     "fig, axes = plt.subplots(1, 3, figsize=(10, 3), tight_layout=True)\n",
     "\n",
-    "for state, ax in zip(states, axes):\n",
+    "for state, ax in zip(states, axes, strict=False):\n",
     "    ax.bar(state.charge_numbers, state.ionic_fractions)\n",
     "    ax.set_title(f\"Ionization state for {state.base_particle}\")\n",
     "    ax.set_xlabel(\"ionic level\")\n",

mypy.ini

@@ -1,5 +1,5 @@
 [mypy]
-python_version = 3.9
+python_version = '3.10'
 mypy_path = ./type_stubs
 exclude = (?x)(
           docs|

plasmapy/analysis/fit_functions.py

@@ -235,7 +235,7 @@ def params(self) -> Optional[tuple]:
     @params.setter
     def params(self, val) -> None:
         if isinstance(val, self.FitParamTuple) or (
-            isinstance(val, (tuple, list))
+            isinstance(val, tuple | list)
             and len(val) == len(self.param_names)
             and all(isinstance(vv, numbers.Real) for vv in val)
         ):
@@ -257,7 +257,7 @@ def param_errors(self) -> Optional[tuple]:
     @param_errors.setter
     def param_errors(self, val) -> None:
         if isinstance(val, self.FitParamTuple) or (
-            isinstance(val, (tuple, list))
+            isinstance(val, tuple | list)
             and len(val) == len(self.param_names)
             and all(isinstance(vv, numbers.Real) for vv in val)
         ):

plasmapy/analysis/swept_langmuir/floating_potential.py

@@ -217,7 +217,7 @@ def find_floating_potential(  # noqa: C901, PLR0912, PLR0915
     # condition min_points
     if min_points is None:
         min_points = int(np.max([5, np.around(min_point_factor * voltage.size)]))
-    elif not isinstance(min_points, (float, np.floating, int, np.integer)):
+    elif not isinstance(min_points, float | np.floating | int | np.integer):
         raise TypeError(
             f"Argument 'min_points' is wrong type '{type(min_points)}', expecting "
             f"an int or float."
@@ -265,7 +265,7 @@ def find_floating_potential(  # noqa: C901, PLR0912, PLR0915
             (cp_candidates[threshold_indices] + 1, [cp_candidates[-1] + 1])
         )
         rtn_extras["islands"] = [
-            slice(start, stop) for start, stop in zip(isl_start, isl_stop)
+            slice(start, stop) for start, stop in zip(isl_start, isl_stop, strict=False)
         ]
 
         # do islands fall within the min_points window?

plasmapy/analysis/swept_langmuir/helpers.py

@@ -71,7 +71,7 @@ def check_sweep(  # noqa: C901, PLR0912
     # check type
     if isinstance(voltage, np.ndarray):
         pass
-    elif isinstance(voltage, (list, tuple)):
+    elif isinstance(voltage, list | tuple):
         voltage = np.array(voltage)
     else:
         raise TypeError(
@@ -102,7 +102,7 @@ def check_sweep(  # noqa: C901, PLR0912
     # check type
     if isinstance(current, np.ndarray):
         pass
-    elif isinstance(current, (list, tuple)):
+    elif isinstance(current, list | tuple):
         current = np.array(current)
     else:
         raise TypeError(

plasmapy/analysis/time_series/conditional_averaging.py

@@ -423,13 +423,16 @@ def is_middle_value_highest(sequence):
 
         if self._reference_signal_provided:
             for event, peak, reference_event in zip(
-                conditional_events, peak_indices, conditional_events_reference_signal
+                conditional_events,
+                peak_indices,
+                conditional_events_reference_signal,
+                strict=False,
             ):
                 if is_middle_value_highest(reference_event):
                     checked_conditional_events.append(event)
                     checked_peak_indices.append(peak)
         else:
-            for event, peak in zip(conditional_events, peak_indices):
+            for event, peak in zip(conditional_events, peak_indices, strict=False):
                 if is_middle_value_highest(event):
                     checked_conditional_events.append(event)
                     checked_peak_indices.append(peak)

plasmapy/diagnostics/thomson.py

@@ -845,7 +845,7 @@ def spectral_density_model(  # noqa: C901, PLR0912, PLR0915
     # **********************
     # Required settings and parameters per population
     # **********************
-    for p, nums in zip(["T_e", "T_i"], [num_e, num_i]):
+    for p, nums in zip(["T_e", "T_i"], [num_e, num_i], strict=False):
         for num in range(nums):
             key = f"{p}_{num!s}"
             if key not in params:

plasmapy/dispersion/analytical/stix_.py

@@ -176,15 +176,15 @@ def stix(  # noqa: C901, PLR0912, PLR0915
     """
 
     # Validate ions argument
-    if not isinstance(ions, (list, tuple, ParticleList)):
+    if not isinstance(ions, list | tuple | ParticleList):
         ions = [ions]
     ions = ParticleList(ions)
 
     if not all(failed := [ion.is_ion and ion.charge_number > 0 for ion in ions]):
         raise ValueError(
             "Particle(s) passed to 'ions' must be a positively charged"
             " ion. The following particle(s) is(are) not allowed "
-            f"{[ion for ion, fail in zip(ions, failed) if not fail]}"
+            f"{[ion for ion, fail in zip(ions, failed, strict=False) if not fail]}"
         )
 
     # Validate n_i argument
@@ -244,15 +244,15 @@ def stix(  # noqa: C901, PLR0912, PLR0915
     # Generate the plasma parameters needed
     wps = []
     wcs = []
-    for par, dens in zip(species, densities):
+    for par, dens in zip(species, densities, strict=False):
         wps.append(plasma_frequency(n=dens * u.m**-3, particle=par).value)
         wcs.append(gyrofrequency(B=B, particle=par, signed=True).value)
 
     # Stix method implemented
     S = np.ones_like(w, dtype=np.float64)
     P = np.ones_like(S)
     D = np.zeros_like(S)
-    for wc, wp in zip(wcs, wps):
+    for wc, wp in zip(wcs, wps, strict=False):
         S -= (wp**2) / (w**2 - wc**2)
         P -= (wp / w) ** 2
         D += ((wp**2) / (w**2 - wc**2)) * (wc / w)

plasmapy/dispersion/analytical/tests/test_stix_.py

@@ -34,15 +34,15 @@ def spd(B, w, ions, n_i):
         # Generate the plasma parameters needed
         wps = []
         wcs = []
-        for par, dens in zip(species, densities):
+        for par, dens in zip(species, densities, strict=False):
             wps.append(plasma_frequency(n=dens * u.m**-3, particle=par).value)
             wcs.append(gyrofrequency(B=B, particle=par, signed=True).value)
 
         # Stix method implemented
         S = np.ones_like(w, dtype=np.float64)
         P = np.ones_like(S)
         D = np.zeros_like(S)
-        for wc, wp in zip(wcs, wps):
+        for wc, wp in zip(wcs, wps, strict=False):
             S -= (wp**2) / (w**2 - wc**2)
             P -= (wp / w) ** 2
             D += ((wp**2) / (w**2 - wc**2)) * (wc / w)

plasmapy/formulary/collisions/helio/collisional_analysis.py

@@ -199,7 +199,7 @@ def temp_ratio(  # noqa: C901
     """
 
     # Validate ions argument
-    if not isinstance(ions, (list, tuple, ParticleList)):
+    if not isinstance(ions, list | tuple | ParticleList):
         ions = [ions]
     ions = ParticleList(ions)
 

plasmapy/formulary/collisions/tests/test_frequencies.py

@@ -409,7 +409,7 @@ def test_limit_values(
             ) ** 2
 
         for attribute_name, expected_limit_value in zip(
-            self.return_values_to_test, expected_limit_values
+            self.return_values_to_test, expected_limit_values, strict=False
         ):
             calculated_limit_value = getattr(value_test_case, attribute_name).value
             # Energy loss limit value is already in units of

plasmapy/formulary/densities.py

@@ -156,7 +156,7 @@ def mass_density(
                 f"(not type {type(particle)}) to calculate the mass density!"
             ) from e
 
-    if not isinstance(z_ratio, (float, np.floating, int, np.integer)):
+    if not isinstance(z_ratio, float | np.floating | int | np.integer):
         raise TypeError(
             f"Expected type int or float for keyword z_ratio, got type {type(z_ratio)}."
         )

plasmapy/formulary/dielectric.py

@@ -117,7 +117,7 @@ def cold_plasma_permittivity_SDP(
     """
     S, D, P = 1, 0, 1
 
-    for s, n_s in zip(species, n):
+    for s, n_s in zip(species, n, strict=False):
         omega_c = gyrofrequency(B=B, particle=s, signed=True)
         omega_p = plasma_frequency(n=n_s, particle=s)
 
@@ -207,7 +207,7 @@ def cold_plasma_permittivity_LRP(
     """
     L, R, P = 1, 1, 1
 
-    for s, n_s in zip(species, n):
+    for s, n_s in zip(species, n, strict=False):
         omega_c = gyrofrequency(B=B, particle=s, signed=True)
         omega_p = plasma_frequency(n=n_s, particle=s)
 

plasmapy/formulary/mathematics.py

@@ -71,7 +71,7 @@ def Fermi_integral(
     >>> Fermi_integral(1, 1)
     (1.8062860704447743-0j)
     """
-    if isinstance(x, (numbers.Integral, numbers.Real, numbers.Complex)):
+    if isinstance(x, numbers.Integral | numbers.Real | numbers.Complex):
         arg = -np.exp(x)
         return -1 * complex(polylog(j + 1, arg))
     elif isinstance(x, np.ndarray):

plasmapy/formulary/relativity.py

@@ -495,7 +495,7 @@ def velocity(self, V: u.Quantity[u.m / u.s]) -> None:
 
     @lorentz_factor.setter
     def lorentz_factor(self, γ: Union[Real, u.Quantity]):
-        if not isinstance(γ, (Real, u.Quantity)):
+        if not isinstance(γ, Real | u.Quantity):
             raise TypeError("Invalid type for Lorentz factor")
 
         if isinstance(γ, u.Quantity):

plasmapy/formulary/speeds.py

@@ -348,7 +348,7 @@ def ion_sound_speed(
     <Quantity 229585... m / s>
 
     """
-    for gamma, species in zip([gamma_e, gamma_i], ["electrons", "ions"]):
+    for gamma, species in zip([gamma_e, gamma_i], ["electrons", "ions"], strict=False):
         if not isinstance(gamma, Real):
             raise TypeError(
                 f"The adiabatic index gamma for {species} must be a positive "

plasmapy/particles/_factory.py

@@ -83,7 +83,7 @@ def _make_custom_particle_with_real_charge_number(
     CustomParticle(mass=6.64511...e-27 kg, charge=2.40326...e-19 C)
     """
 
-    if not isinstance(Z, (Real, u.Quantity)) and Z is not None:
+    if not isinstance(Z, Real | u.Quantity) and Z is not None:
         raise ChargeError("The charge number must be a real number.")
 
     base_particle = Particle(arg, mass_numb=mass_numb, Z=0)
@@ -191,7 +191,7 @@ def _physical_particle_factory(
         with contextlib.suppress(ChargeError, InvalidParticleError, TypeError):
             return constructor(*args, **kwargs)
 
-    if args and not isinstance(args[0], (str, Integral, u.Quantity)):
+    if args and not isinstance(args[0], str | Integral | u.Quantity):
         raise TypeError("Invalid type for particle.")
 
     raise InvalidParticleError(_generate_particle_factory_error_message(args, kwargs))

plasmapy/particles/_parsing.py

@@ -382,7 +382,7 @@ def reconstruct_ion_symbol(
 
         return ion
 
-    if not isinstance(argument, (str, Integral)):
+    if not isinstance(argument, str | Integral):
         raise TypeError(f"The argument {argument} is not an integer or string.")
 
     arg = dealias_particle_aliases(argument)

plasmapy/particles/atomic.py

@@ -563,7 +563,9 @@ def known_isotopes_for_element(argument):
         mass_numbers = [mass_number(isotope) for isotope in isotopes]
         return [
             mass_number
-            for (isotope, mass_number) in sorted(zip(mass_numbers, isotopes))
+            for (isotope, mass_number) in sorted(
+                zip(mass_numbers, isotopes, strict=False)
+            )
         ]
 
     if argument is not None:
@@ -674,7 +676,9 @@ def common_isotopes_for_element(
 
         sorted_isotopes = [
             iso_comp
-            for (isotope, iso_comp) in sorted(zip(isotopic_abundances, CommonIsotopes))
+            for (isotope, iso_comp) in sorted(
+                zip(isotopic_abundances, CommonIsotopes, strict=False)
+            )
         ]
 
         sorted_isotopes.reverse()
@@ -902,7 +906,7 @@ def periodic_table_period(argument: Union[str, Integral]) -> Integral:
     2
     """
     # TODO: Implement @particle_input
-    if not isinstance(argument, (str, Integral)):
+    if not isinstance(argument, str | Integral):
         raise TypeError(
             "The argument to periodic_table_period must be either a "
             "string representing the element or its symbol, or an "
@@ -950,7 +954,7 @@ def periodic_table_group(argument: Union[str, Integral]) -> Integral:
     2
     """
     # TODO: Implement @particle_input
-    if not isinstance(argument, (str, Integral)):
+    if not isinstance(argument, str | Integral):
         raise TypeError(
             "The argument to periodic_table_group must be "
             "either a string representing the element or its "
@@ -1001,7 +1005,7 @@ def periodic_table_block(argument: Union[str, Integral]) -> str:
     's'
     """
     # TODO: Implement @particle_input
-    if not isinstance(argument, (str, Integral)):
+    if not isinstance(argument, str | Integral):
         raise TypeError(
             "The argument to periodic_table_block must be "
             "either a string representing the element or its "
@@ -1047,7 +1051,7 @@ def periodic_table_category(argument: Union[str, Integral]) -> str:
     'transition metal'
     """
     # TODO: Implement @particle_input
-    if not isinstance(argument, (str, Integral)):
+    if not isinstance(argument, str | Integral):
         raise TypeError(
             "The argument to periodic_table_category must be "
             "either a string representing the element or its "

plasmapy/particles/ionization_state_collection.py

@@ -585,7 +585,7 @@ def _sort_entries_by_atomic_and_mass_numbers(k):
 
                 self._pars["abundances"] = new_abundances
 
-        elif isinstance(inputs, (list, tuple)):
+        elif isinstance(inputs, list | tuple):
             try:
                 _particle_instances = [Particle(particle) for particle in inputs]
             except (InvalidParticleError, TypeError) as exc:

plasmapy/particles/nuclear.py

@@ -197,7 +197,7 @@ def process_particles_list(
         if isinstance(unformatted_particles_list, str):
             unformatted_particles_list = [unformatted_particles_list]
 
-        if not isinstance(unformatted_particles_list, (list, tuple)):
+        if not isinstance(unformatted_particles_list, list | tuple):
             raise TypeError(
                 "The input to process_particles_list should be a "
                 "string, list, or tuple."