custom wx_unit validation behavior

CHANGELOG.rst

@@ -75,6 +75,8 @@ ASDF
 
 -  update the default sorting order of ``select_tag`` for ``WeldxConverter`` [:pull:`733`]
 
+-  add custom validation behavior to ``wx_unit`` [:pull:`739`]
+
 deprecations
 ============
 

weldx/asdf/util.py

@@ -8,6 +8,7 @@
 from warnings import warn
 
 import asdf
+import pint
 from asdf.asdf import SerializationContext
 from asdf.config import AsdfConfig, get_config
 from asdf.extension import Extension
@@ -18,6 +19,7 @@
 
 from weldx.asdf.constants import SCHEMA_PATH, WELDX_EXTENSION_URI
 from weldx.asdf.types import WeldxConverter
+from weldx.constants import U_, UNITS_KEY, WELDX_UNIT_REGISTRY
 from weldx.types import (
     SupportsFileReadWrite,
     types_file_like,
@@ -544,6 +546,35 @@ def _get_instance_shape(
     return None
 
 
+def _get_instance_units(
+    instance_dict: Union[TaggedDict, dict[str, Any]]
+) -> Union[pint.Unit, None]:
+    """Get the units of an ASDF instance from its tagged dict form.
+
+    Parameters
+    ----------
+    instance_dict
+        The yaml node to evaluate.
+
+    Returns
+    -------
+    pint.Unit
+        The pint unit or `None` if no unit information is present.
+    """
+    if isinstance(instance_dict, (float, int)):  # base types
+        return WELDX_UNIT_REGISTRY.dimensionless
+    elif isinstance(instance_dict, Mapping) and UNITS_KEY in instance_dict:
+        return U_(str(instance_dict[UNITS_KEY]))  # catch TaggedString as str
+    elif isinstance(instance_dict, asdf.types.tagged.Tagged):
+        # try calling units_from_tagged for custom types
+        if instance_dict._tag.startswith("tag:stsci.edu:asdf/core/ndarray"):
+            return WELDX_UNIT_REGISTRY.dimensionless
+        converter = get_converter_for_tag(instance_dict._tag)
+        if hasattr(converter, "units_from_tagged"):
+            return converter.units_from_tagged(instance_dict)
+    return None
+
+
 class _ProtectedViewDict(MutableMapping):
     def __init__(self, protected_keys, data=None):
         super(_ProtectedViewDict, self).__init__()

weldx/asdf/validators.py

@@ -10,7 +10,7 @@
 from asdf.schema import _type_to_tag
 
 from weldx.asdf.types import WxSyntaxError
-from weldx.asdf.util import _get_instance_shape, uri_match
+from weldx.asdf.util import _get_instance_shape, _get_instance_units, uri_match
 from weldx.constants import U_
 
 __all__ = ["wx_unit_validator", "wx_shape_validator", "wx_property_tag_validator"]
@@ -95,15 +95,21 @@ def _unit_validator(
     if not position:
         position = instance
 
-    unit = instance["units"]
-    unit = str(unit)  # catch TaggedString
-    valid = U_(unit).is_compatible_with(U_(expected_dimensionality))
-    if not valid:
+    units = _get_instance_units(instance)
+    if units is None:
         yield ValidationError(
             f"Error validating unit dimension for property '{position}'. "
             f"Expected unit of dimension '{expected_dimensionality}' "
-            f"but got unit '{unit}'"
+            "but found no unit information"
         )
+    else:
+        valid = units.is_compatible_with(U_(expected_dimensionality))
+        if not valid:
+            yield ValidationError(
+                f"Error validating unit dimension for property '{position}'. "
+                f"Expected unit of dimension '{expected_dimensionality}' "
+                f"but got unit '{units}'"
+            )
 
 
 def _compare(_int, exp_string):

weldx/schemas/weldx.bam.de/weldx/debug/test_unit_validator-0.1.0.yaml

@@ -56,6 +56,10 @@ properties:
     tag: "asdf://weldx.bam.de/weldx/tags/units/quantity-0.1.*"
     wx_unit: "Δ°C"
 
+  dimensionless:
+    description: a basic numeric type without any units or dimensionless quantity
+    wx_unit: " "
+
 required: [length_prop, velocity_prop, current_prop, delta_prop]
 propertyOrder: [length_prop, velocity_prop, current_prop]
 flowStyle: block

weldx/tags/core/data_array.py

@@ -1,12 +1,13 @@
 """Serialization for xarray.DataArray."""
 from __future__ import annotations
 
+import pint
 from asdf.tagged import TaggedDict
 from xarray import DataArray
 
 import weldx.tags.core.common_types as ct
 from weldx.asdf.types import WeldxConverter
-from weldx.asdf.util import _get_instance_shape
+from weldx.asdf.util import _get_instance_shape, _get_instance_units
 
 
 class XarrayDataArrayConverter(WeldxConverter):
@@ -47,3 +48,8 @@ def from_yaml_tree(self, node: dict, tag: str, ctx):
     def shape_from_tagged(node: TaggedDict) -> list[int]:
         """Calculate the shape from static tagged tree instance."""
         return _get_instance_shape(node["data"]["data"])
+
+    @staticmethod
+    def units_from_tagged(node: TaggedDict) -> pint.Unit:
+        """Get the units information from static tagged tree instance."""
+        return _get_instance_units(node["data"])

weldx/tags/debug/test_unit_validator.py

@@ -1,7 +1,9 @@
 from dataclasses import dataclass, field
+from typing import Union
 
 import numpy as np
 import pint
+import xarray as xr
 
 from weldx.asdf.util import dataclass_serialization_class
 from weldx.constants import Q_
@@ -21,6 +23,7 @@ class UnitValidatorTestClass:
     )
     simple_prop: dict = field(default_factory=lambda: dict(value=float(3), units="m"))
     delta_prop: dict = Q_(100, "Δ°C")
+    dimensionless: Union[float, int, np.ndarray, pint.Quantity, xr.DataArray] = 3.14
 
 
 UnitValidatorTestClassConverter = dataclass_serialization_class(

weldx/tests/asdf_tests/test_asdf_validators.py

@@ -2,6 +2,7 @@
 import numpy as np
 import pandas as pd
 import pytest
+import xarray as xr
 from asdf import ValidationError
 
 from weldx.asdf.types import WxSyntaxError
@@ -179,6 +180,9 @@ def test_shape_validator_exceptions(test_input):
     [
         UnitValidatorTestClass(),
         UnitValidatorTestClass(length_prop=Q_(1, "inch")),
+        UnitValidatorTestClass(dimensionless=Q_(1, " ")),
+        UnitValidatorTestClass(dimensionless=np.ones(3)),
+        UnitValidatorTestClass(dimensionless=xr.DataArray(data=Q_(np.ones(3)))),
     ],
 )
 def test_unit_validator(test):
@@ -211,6 +215,12 @@ def test_unit_validator(test):
         UnitValidatorTestClass(
             simple_prop={"value": float(3), "units": "s"},  # wrong unit
         ),
+        UnitValidatorTestClass(
+            dimensionless=Q_(1, "s"),  # wrong unit
+        ),
+        UnitValidatorTestClass(
+            dimensionless=xr.DataArray(data=np.ones(3)),  # xarray must be quantity
+        ),
     ],
 )
 def test_unit_validator_exception(test):