initial fix up of typehints

src/pyhf/schema/__init__.py

@@ -7,9 +7,11 @@
 from pyhf.schema.loader import load_schema
 from pyhf.schema.validator import validate
 from pyhf.schema import variables
-from pyhf.typing import Self, SchemaVersion, Traversable
+from pyhf.typing import Self, SchemaVersion, PathOrStr, Traversable
 from pyhf.schema.upgrader import upgrade
 
+from pathlib import Path
+
 __all__ = [
     "load_schema",
     "validate",
@@ -65,8 +67,7 @@ class Schema(sys.modules[__name__].__class__):  # type: ignore[misc]
 
     """
 
-    # type ignore below, see https://github.com/python/mypy/pull/11666
-    def __call__(self, new_path: Traversable) -> Self:  # type: ignore[valid-type]
+    def __call__(self, new_path: PathOrStr) -> Self:
         """
         Change the local search path for finding schemas locally.
 
@@ -76,7 +77,7 @@ def __call__(self, new_path: Traversable) -> Self:  # type: ignore[valid-type]
         Returns:
             self (pyhf.schema.Schema): Returns itself (for contextlib management)
         """
-        self.orig_path, variables.schemas = variables.schemas, new_path
+        self.orig_path, variables.schemas = variables.schemas, Path(new_path)
         self.orig_cache = dict(variables.SCHEMA_CACHE)
         variables.SCHEMA_CACHE.clear()
         return self
@@ -95,7 +96,7 @@ def __exit__(self, *args: Any, **kwargs: Any) -> None:
         variables.SCHEMA_CACHE = self.orig_cache
 
     @property
-    def path(self) -> Traversable:
+    def path(self) -> Traversable | Path:
         """
         The local path for schemas.
         """

src/pyhf/schema/validator.py

@@ -10,6 +10,14 @@
 from pyhf.schema.loader import load_schema
 from pyhf.typing import Workspace, Model, Measurement, PatchSet
 from typing import Any
+import sys
+
+# importlib.resources.as_file wasn't added until Python 3.9
+# c.f. https://docs.python.org/3.9/library/importlib.html#importlib.resources.as_file
+if sys.version_info >= (3, 9):
+    from importlib import resources
+else:
+    import importlib_resources as resources
 
 log = logging.getLogger(__name__)
 
@@ -84,29 +92,36 @@ def validate(
                 f"Specification requested version {version} but latest is {latest_known_version}. Upgrade your specification or downgrade pyhf."
             )
 
+    if version is None:
+        msg = f'The version for {schema_name} is not set and could not be determined automatically as there is no default version specified for this schema. This could be due to using a schema that pyhf is not aware of, or a mistake.'
+        raise ValueError(msg)
+
     schema = load_schema(str(Path(version).joinpath(schema_name)))
 
-    # note: trailing slash needed for RefResolver to resolve correctly and by
-    # design, pathlib strips trailing slashes. See ref below:
-    # * https://bugs.python.org/issue21039
-    # * https://github.com/python/cpython/issues/65238
-    resolver = jsonschema.RefResolver(
-        base_uri=f"{Path(variables.schemas).joinpath(version).as_uri()}/",
-        referrer=schema_name,
-        store=variables.SCHEMA_CACHE,
-    )
-
-    Validator = jsonschema.Draft202012Validator
-
-    if allow_tensors:
-        type_checker = Validator.TYPE_CHECKER.redefine(
-            "array", _is_array_or_tensor
-        ).redefine("number", _is_number_or_tensor_subtype)
-        Validator = jsonschema.validators.extend(Validator, type_checker=type_checker)
-
-    validator = Validator(schema, resolver=resolver, format_checker=None)
-
-    try:
-        return validator.validate(spec)
-    except jsonschema.ValidationError as err:
-        raise pyhf.exceptions.InvalidSpecification(err, schema_name)  # type: ignore[no-untyped-call]
+    with resources.as_file(variables.schemas) as path:
+        # note: trailing slash needed for RefResolver to resolve correctly and by
+        # design, pathlib strips trailing slashes. See ref below:
+        # * https://bugs.python.org/issue21039
+        # * https://github.com/python/cpython/issues/65238
+        resolver = jsonschema.RefResolver(
+            base_uri=f"{path.joinpath(version).as_uri()}/",
+            referrer=schema_name,
+            store=variables.SCHEMA_CACHE,
+        )
+
+        Validator = jsonschema.Draft202012Validator
+
+        if allow_tensors:
+            type_checker = Validator.TYPE_CHECKER.redefine(
+                "array", _is_array_or_tensor
+            ).redefine("number", _is_number_or_tensor_subtype)
+            Validator = jsonschema.validators.extend(
+                Validator, type_checker=type_checker
+            )
+
+        validator = Validator(schema, resolver=resolver, format_checker=None)
+
+        try:
+            return validator.validate(spec)
+        except jsonschema.ValidationError as err:
+            raise pyhf.exceptions.InvalidSpecification(err, schema_name)  # type: ignore[no-untyped-call]

src/pyhf/schema/variables.py

@@ -2,13 +2,15 @@
 import sys
 from pyhf.typing import Schema, SchemaVersion, Traversable
 
+from pathlib import Path
+
 # importlib.resources.as_file wasn't added until Python 3.9
 # c.f. https://docs.python.org/3.9/library/importlib.html#importlib.resources.as_file
 if sys.version_info >= (3, 9):
     from importlib import resources
 else:
     import importlib_resources as resources
-schemas: Traversable = resources.files('pyhf') / "schemas"
+schemas: Traversable | Path = resources.files('pyhf') / "schemas"
 
 SCHEMA_CACHE: dict[str, Schema] = {}
 SCHEMA_BASE = "https://scikit-hep.org/pyhf/schemas/"