feat(dataset): expose ParamSpecBase from qcodes.dataset

``ParamSpecBase`` is the canonical base class used for building ``InterDependencies_``
graphs on the public API surface, but until now it was only importable from
:mod:`qcodes.parameters`, while :mod:`qcodes.dataset` only re-exported the legacy
:class:`~qcodes.dataset.descriptions.param_spec.ParamSpec` class. Users who followed
the documented dataset-centric entry points had to reach into ``qcodes.parameters``
to construct dependency graphs.

Re-export ``ParamSpecBase`` from ``qcodes.dataset`` and add it to ``__all__`` so the
public namespace matches the actual recommended usage. Adds a regression test that
pins both the re-export and its presence in ``__all__``.

Closes #7369

Signed-off-by: Asish Kumar <officialasishkumar@gmail.com>

Author: officialasishkumar

docs/changes/newsfragments/7369.improved

@@ -0,0 +1,3 @@
+``ParamSpecBase`` is now re-exported from :mod:`qcodes.dataset` so that users
+defining custom ``InterDependencies_`` graphs via the public ``qcodes.dataset``
+namespace do not need to reach into :mod:`qcodes.parameters` to obtain it.

src/qcodes/dataset/__init__.py

@@ -17,6 +17,8 @@
     export_datasets_and_create_metadata_db,
     extract_runs_into_db,
 )
+from qcodes.parameters import ParamSpecBase
+
 from .descriptions.dependencies import InterDependencies_, ParamSpecTree
 from .descriptions.param_spec import ParamSpec
 from .descriptions.rundescriber import RunDescriber
@@ -77,6 +79,7 @@
     "LogSweep",
     "Measurement",
     "ParamSpec",
+    "ParamSpecBase",
     "ParamSpecTree",
     "RunDescriber",
     "SQLiteSettings",

tests/dataset/test_dependencies.py

@@ -17,6 +17,14 @@
 from tests.common import error_caused_by
 
 
+def test_param_spec_base_reexported_from_qcodes_dataset() -> None:
+    """``ParamSpecBase`` is part of the public :mod:`qcodes.dataset` API."""
+    import qcodes.dataset as qdataset
+
+    assert qdataset.ParamSpecBase is ParamSpecBase
+    assert "ParamSpecBase" in qdataset.__all__
+
+
 def test_wrong_input_raises() -> None:
     for pspecs in (
         ["p1", "p2", "p3"],