Add newsfragment for PR #8096

Also deprecate 3 additional pre-existing unused TypeVars in
field_vector.py, threading.py, and channel.py. Fix pyright
errors in test_deprecate.py.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: jenshnielsen

docs/changes/newsfragments/8096.breaking

@@ -0,0 +1,3 @@
+Several module-level ``TypeVar`` definitions that are no longer used internally have been
+deprecated. Importing them will emit a ``QCoDeSDeprecationWarning``. They will be removed
+in a future version.

src/qcodes/dataset/measurements.py

@@ -18,7 +18,7 @@
 from itertools import chain
 from numbers import Number
 from time import perf_counter, perf_counter_ns
-from typing import TYPE_CHECKING, Any, TypeAlias, TypeVar, cast
+from typing import TYPE_CHECKING, Any, TypeAlias, cast
 
 import numpy as np
 import numpy.typing as npt
@@ -804,9 +804,6 @@ def __exit__(
             self._exit_stack.close()
 
 
-T = TypeVar("T", bound="Measurement")
-
-
 class Measurement:
     """
     Measurement procedure container. Note that multiple measurement
@@ -1616,3 +1613,16 @@ def _numeric_values_are_equal(
         ):
             return False
     return True
+
+
+if not TYPE_CHECKING:
+    from typing import TypeVar
+
+    from qcodes.utils.deprecate import _make_deprecated_typevars_getattr
+
+    __getattr__ = _make_deprecated_typevars_getattr(
+        __name__,
+        {
+            "T": TypeVar("T", bound="Measurement"),
+        },
+    )

src/qcodes/dataset/threading.py

@@ -24,8 +24,6 @@
 ParamMeasT: TypeAlias = "ParameterBase | Callable[[], None]"
 OutType: TypeAlias = "list[tuple[ParameterBase, ValuesType]]"
 
-T = TypeVar("T")
-
 _LOG = logging.getLogger(__name__)
 
 
@@ -221,3 +219,13 @@ def __exit__(
         exc_tb: TracebackType | None,
     ) -> None:
         self._thread_pool.__exit__(exc_type, exc_val, exc_tb)
+
+
+if not TYPE_CHECKING:
+    from qcodes.utils.deprecate import _make_deprecated_typevars_getattr
+
+    _deprecated_typevars: dict[str, TypeVar] = {
+        "T": TypeVar("T"),
+    }
+
+    __getattr__ = _make_deprecated_typevars_getattr(__name__, _deprecated_typevars)

src/qcodes/extensions/parameters/parameter_mixin.py

@@ -24,12 +24,10 @@
 
 import logging
 import warnings
-from typing import Any, ClassVar, TypeVar
+from typing import TYPE_CHECKING, Any, ClassVar
 
 from qcodes.parameters import ParameterBase
 
-T = TypeVar("T")
-
 log = logging.getLogger(__name__)
 
 
@@ -245,7 +243,7 @@ def _update_docstring(
         cls.__doc__ = (original_doc.strip() + "\n\n" + additional_doc).strip()
 
     @classmethod
-    def _get_leaf_classes(
+    def _get_leaf_classes[T](
         cls, base_type: type[T], exclude_base_type: type | None = None
     ) -> list[type[T]]:
         """
@@ -289,7 +287,7 @@ def _get_leaf_classes(
         return leaf_classes
 
     @classmethod
-    def _get_mixin_classes(
+    def _get_mixin_classes[T](
         cls, base_type: type[T], exclude_base_type: type | None = None
     ) -> list[type[T]]:
         """
@@ -321,3 +319,16 @@ def _get_mixin_classes(
             ]
 
         return mixin_classes
+
+
+if not TYPE_CHECKING:
+    from typing import TypeVar
+
+    from qcodes.utils.deprecate import _make_deprecated_typevars_getattr
+
+    __getattr__ = _make_deprecated_typevars_getattr(
+        __name__,
+        {
+            "T": TypeVar("T"),
+        },
+    )

src/qcodes/instrument/channel.py

@@ -15,7 +15,6 @@
     MultiParameter,
     Parameter,
 )
-from qcodes.parameters.multi_channel_instrument_parameter import InstrumentModuleType
 from qcodes.utils import full_class
 from qcodes.validators import Validator
 
@@ -27,6 +26,7 @@
     from .instrument_base import InstrumentBaseKWArgs
 
 
+# Cannot convert to PEP 695: uses default= and covariant= which require PEP 696 (Python 3.13+).
 _TIB_co = TypeVar(
     "_TIB_co", bound="InstrumentBase", default=InstrumentBase, covariant=True
 )
@@ -98,10 +98,7 @@ class InstrumentChannel(InstrumentModule[_TIB_co], Generic[_TIB_co]):
     pass
 
 
-T = TypeVar("T", bound="ChannelTuple")
-
-
-class ChannelTuple(MetadatableWithName, Sequence[InstrumentModuleType]):
+class ChannelTuple[InstrumentModuleType: "InstrumentModule"](MetadatableWithName, Sequence[InstrumentModuleType]):
     """
     Container for channelized parameters that allows for sweeps over
     all channels, as well as addressing of individual channels.
@@ -628,7 +625,7 @@ def invalidate_cache(self) -> None:
 
 # in index method the parameter obj should be called value but that would
 # be an incompatible change
-class ChannelList(  #  pyright: ignore[reportIncompatibleMethodOverride]
+class ChannelList[InstrumentModuleType: "InstrumentModule"](  #  pyright: ignore[reportIncompatibleMethodOverride]
     ChannelTuple[InstrumentModuleType], MutableSequence[InstrumentModuleType]
 ):
     """
@@ -1161,10 +1158,8 @@ def exists_on_instrument(self) -> bool:
         return self._exists_on_instrument
 
 
-TAUTORELOADCHANNEL = TypeVar("TAUTORELOADCHANNEL", bound=AutoLoadableInstrumentChannel)
 
-
-class AutoLoadableChannelList(ChannelList[TAUTORELOADCHANNEL]):
+class AutoLoadableChannelList[TAUTORELOADCHANNEL: AutoLoadableInstrumentChannel](ChannelList[TAUTORELOADCHANNEL]):
     """
     Extends the QCoDeS :class:`ChannelList` class to add the following features:
     - Automatically create channel objects on initialization
@@ -1243,3 +1238,16 @@ def add(self, **kwargs: Any) -> TAUTORELOADCHANNEL:
 
         self.append(new_channel)
         return new_channel
+
+
+if not TYPE_CHECKING:
+    from qcodes.utils.deprecate import _make_deprecated_typevars_getattr
+
+    _deprecated_typevars: dict[str, TypeVar] = {
+        "T": TypeVar("T", bound="ChannelTuple"),
+        "TAUTORELOADCHANNEL": TypeVar(
+            "TAUTORELOADCHANNEL", bound=AutoLoadableInstrumentChannel
+        ),
+    }
+
+    __getattr__ = _make_deprecated_typevars_getattr(__name__, _deprecated_typevars)

src/qcodes/instrument/instrument.py

@@ -5,7 +5,7 @@
 import logging
 import time
 import weakref
-from typing import TYPE_CHECKING, Any, Protocol, TypeVar, overload
+from typing import TYPE_CHECKING, Any, Protocol, overload
 
 from qcodes.utils import strip_attrs
 from qcodes.validators import Anything
@@ -31,7 +31,6 @@ def ask(self, cmd: str) -> str: ...
     def write(self, cmd: str) -> None: ...
 
 
-T = TypeVar("T", bound="Instrument")
 
 # a metaclass that overrides __call__ means that we lose
 # both the args and return type hints.
@@ -280,10 +279,10 @@ def find_instrument(
 
     @overload
     @classmethod
-    def find_instrument(cls, name: str, instrument_class: type[T]) -> T: ...
+    def find_instrument[T: "Instrument"](cls, name: str, instrument_class: type[T]) -> T: ...
 
     @classmethod
-    def find_instrument(
+    def find_instrument[T: "Instrument"](
         cls, name: str, instrument_class: type[T] | None = None
     ) -> T | Instrument:
         """
@@ -504,3 +503,16 @@ def find_or_create_instrument[T: "Instrument"](
             instrument.connect_message()  # prints the message
 
     return instrument
+
+
+if not TYPE_CHECKING:
+    from typing import TypeVar
+
+    from qcodes.utils.deprecate import _make_deprecated_typevars_getattr
+
+    __getattr__ = _make_deprecated_typevars_getattr(
+        __name__,
+        {
+            "T": TypeVar("T", bound="Instrument"),
+        },
+    )

src/qcodes/instrument/instrument_base.py

@@ -27,6 +27,7 @@
 
 log = logging.getLogger(__name__)
 
+# Cannot convert to PEP 695: uses default= which requires PEP 696 (Python 3.13+).
 TParameter = TypeVar("TParameter", bound="ParameterBase", default="Parameter")
 TSubmodule = TypeVar(
     "TSubmodule", bound="InstrumentModule | ChannelTuple", default="InstrumentModule"

src/qcodes/instrument_drivers/AlazarTech/ATS.py

@@ -6,7 +6,7 @@
 import time
 import warnings
 from contextlib import contextmanager
-from typing import TYPE_CHECKING, Any, TypeVar, cast
+from typing import TYPE_CHECKING, Any, cast
 
 import numpy as np
 import numpy.typing as npt
@@ -24,8 +24,6 @@
 
 logger = logging.getLogger(__name__)
 
-OutputType = TypeVar("OutputType")
-
 CtypesTypes = (
     type[ctypes.c_uint8]
     | type[ctypes.c_uint16]
@@ -308,7 +306,7 @@ def allocate_and_post_buffer(
         )
         return buffer
 
-    def acquire(  # noqa: D417 (missing args documentation)
+    def acquire[OutputType](  # noqa: D417 (missing args documentation)
         self,
         mode: str | None = None,
         samples_per_record: int | None = None,
@@ -932,3 +930,16 @@ def _get_alazar(self) -> AlazarTechATS:
         :return: reference to the Alazar instrument
         """
         return self._alazar
+
+
+if not TYPE_CHECKING:
+    from typing import TypeVar
+
+    from qcodes.utils.deprecate import _make_deprecated_typevars_getattr
+
+    __getattr__ = _make_deprecated_typevars_getattr(
+        __name__,
+        {
+            "OutputType": TypeVar("OutputType"),
+        },
+    )

src/qcodes/instrument_drivers/Keithley/Keithley_6500.py

@@ -1,5 +1,5 @@
 from functools import partial
-from typing import TYPE_CHECKING, TypeVar
+from typing import TYPE_CHECKING
 
 from qcodes.instrument import VisaInstrument, VisaInstrumentKWArgs
 from qcodes.validators import Bool, Enum, Ints, MultiType, Numbers
@@ -10,8 +10,6 @@
 
     from qcodes.parameters import Parameter
 
-T = TypeVar("T")
-
 
 def _parse_output_string(string_value: str) -> str:
     """Parses and cleans string output of the multimeter. Removes the surrounding
@@ -258,7 +256,7 @@ def reset(self) -> None:
     def _read_next_value(self) -> float:
         return float(self.ask("READ?"))
 
-    def _get_mode_param(self, parameter: str, parser: "Callable[[str], T]") -> T:
+    def _get_mode_param[T](self, parameter: str, parser: "Callable[[str], T]") -> T:
         """Reads the current mode of the multimeter and ask for the given parameter.
 
         Args:
@@ -287,3 +285,16 @@ def _set_mode_param(self, parameter: str, value: str | float | bool) -> None:
         mode = _parse_output_string(self._mode_map[self.mode()])
         cmd = f"{mode}:{parameter} {value}"
         self.write(cmd)
+
+
+if not TYPE_CHECKING:
+    from typing import TypeVar
+
+    from qcodes.utils.deprecate import _make_deprecated_typevars_getattr
+
+    __getattr__ = _make_deprecated_typevars_getattr(
+        __name__,
+        {
+            "T": TypeVar("T"),
+        },
+    )

src/qcodes/instrument_drivers/Keysight/Keysight_N9030B.py

@@ -25,6 +25,7 @@
     from collections.abc import Callable
     from typing import Unpack
 
+# Cannot convert to PEP 695: uses default= which requires PEP 696 (Python 3.13+).
 _T = TypeVar(
     "_T",
     bound="KeysightN9030BSpectrumAnalyzerMode | KeysightN9030BPhaseNoiseMode",