Validate dimension when instantiating datamodel from shape (#395)

changes/395.bugfix.rst

@@ -0,0 +1 @@
+Validate dimension against schema when instantiating datamodel from array shape

src/stdatamodels/jwst/datamodels/tests/test_models.py

@@ -142,7 +142,7 @@ class _NonstandardPrimaryArrayModel(JwstDataModel):
         def get_primary_array_name(self):
             return "wavelength"
 
-    m = _NonstandardPrimaryArrayModel((10,))
+    m = _NonstandardPrimaryArrayModel((10, 10))
     assert "wavelength" in list(m.keys())
     assert m.wavelength.sum() == 0
 

src/stdatamodels/properties.py

@@ -181,6 +181,7 @@ def _make_default_array(attr, schema, ctx):
     if attr == primary_array_name:
         if ctx.shape is not None:
             shape = ctx.shape
+            _validate_primary_shape(schema, shape)
         elif ndim is not None:
             shape = tuple([0] * ndim)
         else:
@@ -222,6 +223,34 @@ def _make_default_array(attr, schema, ctx):
     return array
 
 
+def _validate_primary_shape(schema, shape):
+    """
+    Ensure requested shape is allowed by schema.
+
+    Parameters
+    ----------
+    schema : dict
+        The schema for the primary array.
+    shape : tuple
+        The requested shape of the default array.
+
+    Raises
+    ------
+    ValueError
+        If the requested has dimensions different from the schema's ndim,
+        or larger than the schema's max_ndim.
+    """
+    ndim_requested = len(shape)
+    max_ndim = schema.get("max_ndim", None)
+    ndim = schema.get("ndim", None)
+    if (ndim is not None) and (ndim_requested != ndim):
+        msg = f"Array has wrong number of dimensions. Expected {ndim}, got {ndim_requested}"
+        raise ValueError(msg)
+    if (max_ndim is not None) and (ndim_requested > max_ndim):
+        msg = f"Array has wrong number of dimensions. Expected <= {max_ndim}, got {ndim_requested}"
+        raise ValueError(msg)
+
+
 def _make_default(attr, schema, ctx):
     if "max_ndim" in schema or "ndim" in schema or "datatype" in schema:
         return _make_default_array(attr, schema, ctx)

tests/test_models.py

@@ -100,6 +100,22 @@ def test_init_with_array2():
             dm.data  # noqa: B018
 
 
+def test_init_invalid_shape():
+    """Requested some number of dimensions unequal to ndim, which is set to 2"""
+    with pytest.raises(ValueError):
+        BasicModel((50,))
+
+
+def test_init_invalid_shape2():
+    """Requested more dimensions than max_ndim"""
+    with BasicModel() as dm:
+        schema = dm._schema
+    schema["properties"]["data"]["max_ndim"] = 1
+    schema["properties"]["data"]["ndim"] = None
+    with pytest.raises(ValueError):
+        BasicModel((50, 50), schema=schema)
+
+
 def test_set_array():
     with pytest.raises(ValueError):
         with BasicModel() as dm: