Add checks when coercing between containers that have different profiles

remerkleable/complex.py

@@ -5,7 +5,8 @@
 from collections.abc import Sequence as ColSequence
 from itertools import chain
 import io
-from remerkleable.core import View, BasicView, OFFSET_BYTE_LENGTH, ViewHook, ObjType, ObjParseException
+from remerkleable.core import View, BackedView, BasicView, OFFSET_BYTE_LENGTH,\
+    ViewHook, ObjType, ObjParseException
 from remerkleable.basic import uint256, uint8, uint32
 from remerkleable.tree import Node, subtree_fill_to_length, subtree_fill_to_contents,\
     zero_node, Gindex, PairNode, to_gindex, NavigationError, get_depth, RIGHT_GINDEX
@@ -283,7 +284,9 @@ def __new__(cls, *args, backing: Optional[Node] = None, hook: Optional[ViewHook]
                 raise Exception(f"too many list inputs: {len(vals)}, limit is: {limit}")
             input_views = []
             for el in vals:
-                if isinstance(el, View):
+                if isinstance(el, BackedView):
+                    input_views.append(elem_cls(backing=el.get_backing()))
+                elif isinstance(el, View):
                     input_views.append(el)
                 else:
                     input_views.append(elem_cls.coerce_view(el))
@@ -527,7 +530,9 @@ def __new__(cls, *args, backing: Optional[Node] = None, hook: Optional[ViewHook]
                 raise Exception(f"invalid inputs length: {len(vals)}, vector length is: {vector_length}")
             input_views = []
             for el in vals:
-                if isinstance(el, View):
+                if isinstance(el, BackedView):
+                    input_views.append(elem_cls(backing=el.get_backing()))
+                elif isinstance(el, View):
                     input_views.append(el)
                 else:
                     input_views.append(elem_cls.coerce_view(el))
@@ -731,7 +736,9 @@ def __new__(cls, *args, backing: Optional[Node] = None, hook: Optional[ViewHook]
             fnode: Node
             if fkey in kwargs:
                 finput = kwargs.pop(fkey)
-                if isinstance(finput, View):
+                if isinstance(finput, BackedView):
+                    fnode = ftyp(backing=finput.get_backing()).get_backing()
+                elif isinstance(finput, View):
                     fnode = finput.get_backing()
                 else:
                     fnode = ftyp.coerce_view(finput).get_backing()

remerkleable/stable_container.py

@@ -11,7 +11,7 @@
 from remerkleable.byte_arrays import ByteList, ByteVector
 from remerkleable.complex import ComplexView, Container, FieldOffset, List, Vector, \
     decode_offset, encode_offset
-from remerkleable.core import View, ViewHook, ViewMeta, OFFSET_BYTE_LENGTH
+from remerkleable.core import BackedView, View, ViewHook, ViewMeta, OFFSET_BYTE_LENGTH
 from remerkleable.tree import Gindex, NavigationError, Node, PairNode, \
     get_depth, subtree_fill_to_contents, zero_node, \
     RIGHT_GINDEX
@@ -84,7 +84,9 @@ def __new__(cls, backing: Optional[Node] = None, hook: Optional[ViewHook] = None
                 fnode = zero_node(0)
                 active_fields.set(findex, False)
             else:
-                if isinstance(finput, View):
+                if isinstance(finput, BackedView):
+                    fnode = ftyp(backing=finput.get_backing()).get_backing()
+                elif isinstance(finput, View):
                     fnode = finput.get_backing()
                 else:
                     fnode = ftyp.coerce_view(finput).get_backing()
@@ -330,6 +332,15 @@ def __new__(cls, backing: Optional[Node] = None, hook: Optional[ViewHook] = None
         if backing is not None:
             if len(kwargs) != 0:
                 raise Exception('Cannot have both a backing and elements to init fields')
+            active_fields = Bitvector[cls.B.N].view_from_backing(backing.get_right())
+            for fkey, (findex, _) in cls.B._field_indices.items():
+                if fkey not in cls._field_indices:
+                    if active_fields.get(findex):
+                        raise ValueError(f'Cannot convert to `{cls.__name__}`: {fkey} unsupported')
+                else:
+                    (_, _, fopt) = cls._field_indices[fkey]
+                    if not fopt and not active_fields.get(findex):
+                        raise ValueError(f'Cannot convert to `{cls.__name__}`: {fkey} is required')
             return super().__new__(cls, backing=backing, hook=hook, **kwargs)
 
         extra_kw = kwargs.copy()

remerkleable/test_impl.py

@@ -706,6 +706,10 @@ class ShapePairRepr(Container):
         square = Square(radius=0x42, color=1)
     with pytest.raises(Exception):
         circle = Circle(side=0x42, color=1)
+    with pytest.raises(Exception):
+        square = Square.coerce_view(Shape(radius=0x42, color=1))
+    with pytest.raises(Exception):
+        square = Square(backing=Circle(radius=0x42, color=1).get_backing())
 
     # Surrounding container tests
     class ShapeContainer(Container):
@@ -741,6 +745,34 @@ class ShapeContainerRepr(Container):
         ),
     ).hash_tree_root()
 
+    # Unsupported surrounding container tests
+    with pytest.raises(Exception):
+        shapes = List[Square, 5].coerce_view(
+            List[Circle, 5](Circle(radius=0x42, color=1)))
+    with pytest.raises(Exception):
+        shapes = Vector[Square, 1].coerce_view(
+            Vector[Circle, 1](Circle(radius=0x42, color=1)))
+
+    class SquareContainer(Container):
+        shape: Square
+
+    class CircleContainer(Container):
+        shape: Circle
+
+    with pytest.raises(Exception):
+        shape = SquareContainer.coerce_view(
+            CircleContainer(shape=Circle(radius=0x42, color=1)))
+
+    class SquareStableContainer(StableContainer[1]):
+        shape: Optional[Square]
+
+    class CircleStableContainer(StableContainer[1]):
+        shape: Optional[Circle]
+
+    with pytest.raises(Exception):
+        shape = SquareStableContainer.coerce_view(
+            CircleStableContainer(shape=Circle(radius=0x42, color=1)))
+
     # basic container
     class Shape1(StableContainer[4]):
         side: Optional[uint16]