Attribute validation on assignment

CONTRIBUTING.rst

@@ -332,8 +332,11 @@ Notes on attrs
 IOData uses the `attrs`_ library, not to be confused with the `attr`_ library,
 for classes representing data loaded from files: ``IOData``, ``MolecularBasis``,
 ``Shell``, ``MolecularOrbitals`` and ``Cube``. This enables basic attribute
-validation, which eliminates potentially silly bugs. The following two tricks
-might be convenient with working with these classes:
+validation, which eliminates potentially silly bugs.
+(See ``iodata/attrutils.py`` and the usage of ``validate_shape`` in all those
+classes.)
+
+The following two tricks might be convenient with working with these classes:
 
 - The data can be turned into plain Python data types with the ``attr.asdict``
   function. Make sure you add the ``retain_collection_types=True`` option, to
@@ -347,15 +350,46 @@ might be convenient with working with these classes:
       iodata = load_one("example.xyz")
       fields = attr.asdict(iodata, retain_collection_types=True)
 
-- A shallow copy with a few modified attributes can be created with the evolve
-  method, which is a wrapper for ``attr.evolve``:
+  A similar ``astuple`` function works as you would expect.
+
+- A `shallow copy`_ with a few modified attributes can be created with the
+  evolve method, which is a wrapper for ``attr.evolve``:
 
   .. code-block:: python
 
       from iodata import load_one
       import attr
       iodata1 = load_one("example.xyz")
-      iodata2 = iodata1.evolve(title="another title")
+      iodata2 = attr.evolve(iodata1, title="another title")
+
+  The usage of evolve becomes mandatory when you want to change two or more
+  attributes whose shape need to be consistent. For example, the following
+  would fail:
+
+  .. code-block:: python
+
+      from iodata import IOData
+      iodata = IOData(atnums=[7, 7], atcoords=[[0, 0, 0], [2, 0, 0]])
+      # The next line will fail because the size of atnums and atcoords
+      # becomes inconsistent.
+      iodata.atnums = [8, 8, 8]
+      iodata.atcoords = [[0, 0, 0], [2, 0, 1], [4, 0, 0]]
+
+  The following code, which has the same intent, does work:
+
+  .. code-block:: python
+
+      from iodata import IOData
+      import attr
+      iodata1 = IOData(atnums=[7, 7], atcoords=[[0, 0, 0], [2, 0, 0]])
+      iodata2 = attr.evolve(
+          iodata1,
+          atnums=[8, 8, 8],
+          atcoords=[[0, 0, 0], [2, 0, 1], [4, 0, 0]],
+      )
+
+   For brevity, lists (of lists) were used in these examples. These are always
+   converted to arrays by the constructor or when assigning them to attributes.
 
 
 .. _Bash: https://en.wikipedia.org/wiki/Bash_(Unix_shell)
@@ -364,3 +398,4 @@ might be convenient with working with these classes:
 .. _PEP 0563: https://www.python.org/dev/peps/pep-0563/
 .. _attrs: https://www.attrs.org/en/stable/
 .. _attr: https://github.com/denis-ryzhkov/attr
+.. _shallow copy: https://docs.python.org/3/library/copy.html?highlight=shallow

iodata/basis.py

@@ -85,7 +85,8 @@ def angmom_its(angmom: Union[int, List[int]]) -> Union[str, List[str]]:
     return ANGMOM_CHARS[angmom]
 
 
-@attr.s(auto_attribs=True, slots=True)
+@attr.s(auto_attribs=True, slots=True,
+        on_setattr=[attr.setters.validate, attr.setters.convert])
 class Shell:
     """A shell in a molecular basis representing (generalized) contractions with the same exponents.
 
@@ -141,7 +142,8 @@ def ncon(self) -> int:   # noqa: D401
         return len(self.angmoms)
 
 
-@attr.s(auto_attribs=True, slots=True)
+@attr.s(auto_attribs=True, slots=True,
+        on_setattr=[attr.setters.validate, attr.setters.convert])
 class MolecularBasis:
     """A complete molecular orbital or density basis set.
 

iodata/iodata.py

@@ -32,7 +32,8 @@
 
 
 # pylint: disable=too-many-instance-attributes
-@attr.s(auto_attribs=True, slots=True)
+@attr.s(auto_attribs=True, slots=True,
+        on_setattr=[attr.setters.validate, attr.setters.convert])
 class IOData:
     """A container class for data loaded from (or to be written to) a file.
 

iodata/orbitals.py

@@ -28,7 +28,8 @@
 __all__ = ['MolecularOrbitals']
 
 
-@attr.s(auto_attribs=True, slots=True)
+@attr.s(auto_attribs=True, slots=True,
+        on_setattr=[attr.setters.validate, attr.setters.convert])
 class MolecularOrbitals:
     """Class of Orthonormal Molecular Orbitals.
 

iodata/test/test_attrutils.py

@@ -27,7 +27,7 @@
 from ..attrutils import convert_array_to, validate_shape
 
 
-@attr.s(slots=True)
+@attr.s(auto_attribs=True, slots=True, on_setattr=attr.setters.convert)
 class FooBar:
     """Just a silly class for testing convert_array_to."""
 
@@ -46,9 +46,6 @@ def test_convert_array_to_init():
     assert_allclose(fb.spam, spam2)
 
 
-# converter is not called when assigning!
-# See https://github.com/python-attrs/attrs/issues/645
-@pytest.mark.skip
 def test_convert_array_to_assign():
     fb = FooBar(spam=None)
     assert fb.spam is None
@@ -63,22 +60,21 @@ def test_convert_array_to_assign():
     assert fb.spam is None
 
 
-@attr.s(slots=True, frozen=True)
+@attr.s(auto_attribs=True, slots=True, on_setattr=attr.setters.validate)
 class Spam:
     """Just a silly class for testing validate_shape."""
 
-    egg0: np.ndarray = attr.ib(validator=validate_shape(1, None, "negg"))
-    egg1: np.ndarray = attr.ib(validator=validate_shape("negg", ("egg2", 1)))
+    egg0: np.ndarray = attr.ib(validator=validate_shape(1, None, None))
+    egg1: np.ndarray = attr.ib(validator=validate_shape(("egg0", 2), ("egg2", 1)))
     egg2: np.ndarray = attr.ib(validator=validate_shape(2, ("egg1", 1)))
     egg3: np.ndarray = attr.ib(validator=validate_shape(("leg", 0)))
-    negg: int = attr.ib(converter=int)
     leg: str = attr.ib(validator=validate_shape(("egg3", 0)))
 
 
 def test_validate_shape_init():
     # Construct a Spam instance with valid arguments. This should just work
     spam = Spam(
-        np.zeros((1, 7, 4)), np.zeros((4, 3)), np.zeros((2, 3)), np.zeros(5), 4, "abcde"
+        np.zeros((1, 7, 4)), np.zeros((4, 3)), np.zeros((2, 3)), np.zeros(5), "abcde"
     )
     # Double check
     attr.validate(spam)
@@ -89,7 +85,6 @@ def test_validate_shape_init():
             np.zeros((4, 3)),
             np.zeros((2, 3)),
             np.zeros(5),
-            4,
             "abcde",
         )
     with pytest.raises(TypeError):
@@ -98,7 +93,6 @@ def test_validate_shape_init():
             np.zeros((4, 3)),
             np.zeros((2, 3)),
             np.zeros(5),
-            4,
             "abcde",
         )
     with pytest.raises(TypeError):
@@ -107,7 +101,6 @@ def test_validate_shape_init():
             np.zeros((1, 3)),
             np.zeros((2, 3)),
             np.zeros(5),
-            4,
             "abcde",
         )
     with pytest.raises(TypeError):
@@ -116,7 +109,6 @@ def test_validate_shape_init():
             np.zeros((4, 9)),
             np.zeros((2, 3)),
             np.zeros(5),
-            4,
             "abcde",
         )
     with pytest.raises(TypeError):
@@ -125,7 +117,6 @@ def test_validate_shape_init():
             np.zeros((4, 3)),
             np.zeros((2, 3)),
             np.zeros(5),
-            15,
             "abcde",
         )
     with pytest.raises(TypeError):
@@ -139,13 +130,10 @@ def test_validate_shape_init():
         )
 
 
-# validator is not called when assigning.
-# See https://github.com/python-attrs/attrs/issues/645
-@pytest.mark.skip
 def test_validate_shape_assign():
     # Construct a Spam instance with valid arguments. This should just work
     spam = Spam(
-        np.zeros((1, 7, 4)), np.zeros((4, 3)), np.zeros((2, 3)), np.zeros(5), 4, "abcde"
+        np.zeros((1, 7, 4)), np.zeros((4, 3)), np.zeros((2, 3)), np.zeros(5), "abcde"
     )
     # Double check
     attr.validate(spam)
@@ -158,8 +146,6 @@ def test_validate_shape_assign():
         spam.egg1 = np.zeros((1, 3))
     with pytest.raises(TypeError):
         spam.egg1 = np.zeros((4, 9))
-    with pytest.raises(TypeError):
-        spam.negg = 15
     with pytest.raises(TypeError):
         spam.leg = "abcd"
 

iodata/utils.py

@@ -119,7 +119,8 @@ def back(self, line):
         self.lineno -= 1
 
 
-@attr.s(auto_attribs=True, slots=True)
+@attr.s(auto_attribs=True, slots=True,
+        on_setattr=[attr.setters.validate, attr.setters.convert])
 class Cube:
     """The volumetric data from a cube (or similar) file.
 

setup.py

@@ -74,6 +74,6 @@ def get_readme():
         'Intended Audience :: Science/Research',
     ],
     setup_requires=['numpy>=1.0'],
-    install_requires=['numpy>=1.0', 'scipy', 'attrs>=19.1.0',
+    install_requires=['numpy>=1.0', 'scipy', 'attrs>=20.1.0',
                       'importlib_resources; python_version < "3.7"'],
 )

tools/conda.recipe/meta.yaml

@@ -20,7 +20,7 @@ requirements:
   run:
     - python
     - scipy
-    - attrs >=19.1.0
+    - attrs >=20.1.0
     - importlib_resources  # [py<37]
 
 test: