Deprecations for RFC 73.

Author: zyp

amaranth/lib/data.py

@@ -777,7 +777,10 @@ def eq(self, other):
         """
         if isinstance(other, ValueCastable):
             if not self.shape() == Layout.cast(other.shape()):
-                raise TypeError(f"Cannot assign value with shape {other.shape()} to view with layout {self.shape()}")
+                #raise TypeError(f"Cannot assign value with shape {other.shape()} to view with layout {self.shape()}")
+                # TODO(amaranth-0.7): remove
+                warnings.warn(f"Assigning value with shape {other.shape()} to view with layout {self.shape()} will "
+                            "become an error in Amaranth 0.7", DeprecationWarning, stacklevel=2)
         return self.as_value().eq(other)
 
     def __getitem__(self, key):

amaranth/lib/enum.py

@@ -250,7 +250,10 @@ def eq(self, other):
         """
         if isinstance(other, ValueCastable):
             if not self.shape() == other.shape():
-                raise TypeError(f"Cannot assign value with shape {other.shape()} to value with shape {self.shape()}")
+                #raise TypeError(f"Cannot assign value with shape {other.shape()} to value with shape {self.shape()}")
+                # TODO(amaranth-0.7): remove
+                warnings.warn(f"Assigning value with shape {other.shape()} to value with shape {self.shape()} will "
+                            "become an error in Amaranth 0.7", DeprecationWarning, stacklevel=2)
         return self.as_value().eq(other)
 
     def __add__(self, other):

amaranth/lib/wiring.py

@@ -1596,9 +1596,13 @@ def connect_value(*, out_path, in_path, src_loc_at):
                 try:
                     eq = in_value.eq
                 except AttributeError:
-                    raise ConnectionError(
-                        f"Cannot connect input member {_format_path(in_path)} because the input "
-                        f"value {in_value!r} does not support assignment")
+                    #raise ConnectionError(
+                    #    f"Cannot connect input member {_format_path(in_path)} because the input "
+                    #    f"value {in_value!r} does not support assignment")
+                    # TODO(amaranth-0.7): remove
+                    warnings.warn(f"ValueCastable input value {in_value!r} does not support assignment; "
+                                "this will become an error in Amaranth 0.7", DeprecationWarning, stacklevel=2)
+                    eq = Value.cast(in_value).eq
                 # The `eq()` method may take a `src_loc_at` argument; provide it if it does.
                 if 'src_loc_at' in inspect.signature(eq).parameters:
                     kwargs = {'src_loc_at': src_loc_at + 1}
@@ -1607,9 +1611,13 @@ def connect_value(*, out_path, in_path, src_loc_at):
                 try:
                     connections.append(eq(out_value, **kwargs))
                 except Exception as e:
-                    raise ConnectionError(
-                        f"Cannot connect input member {_format_path(in_path)} to output member "
-                        f"{_format_path(out_path)} because assignment failed") from e
+                    #raise ConnectionError(
+                    #    f"Cannot connect input member {_format_path(in_path)} to output member "
+                    #    f"{_format_path(out_path)} because assignment failed") from e
+                    # TODO(amaranth-0.7): remove
+                    warnings.warn(f"Assigning to ValueCastable input value {in_value!r} failed; "
+                                "this will become an error in Amaranth 0.7", DeprecationWarning, stacklevel=2)
+                    connections.append(Value.cast(in_value).eq(out_value, src_loc_at=src_loc_at + 1))
             def connect_dimensions(dimensions, *, out_path, in_path, src_loc_at):
                 if not dimensions:
                     return connect_value(out_path=out_path, in_path=in_path, src_loc_at=src_loc_at)

tests/test_lib_data.py

@@ -1354,8 +1354,11 @@ class S2(data.Struct):
 
         s = Signal(S)
         s2 = Signal(S2)
-        with self.assertRaisesRegex(TypeError,
-                r"^Cannot assign value with shape <class '.+?\.S2'> to view with layout <class '.+?\.S'>$"):
+        #with self.assertRaisesRegex(TypeError,
+        #        r"^Cannot assign value with shape <class '.+?\.S2'> to view with layout <class '.+?\.S'>$"):
+        # TODO(amaranth-0.7): remove
+        with self.assertWarnsRegex(DeprecationWarning,
+                r"^Assigning value with shape .* to view with layout .* will become an error in Amaranth 0.7$"):
             s.eq(s2)
 
 

tests/test_lib_enum.py

@@ -350,6 +350,9 @@ class EnumB(Enum, shape=unsigned(2)):
 
         s = Signal(EnumA)
         s2 = Signal(EnumB)
-        with self.assertRaisesRegex(TypeError,
-                r"^Cannot assign value with shape <enum 'EnumB'> to value with shape <enum 'EnumA'>$"):
+        #with self.assertRaisesRegex(TypeError,
+        #        r"^Cannot assign value with shape <enum 'EnumB'> to value with shape <enum 'EnumA'>$"):
+        # TODO(amaranth-0.7): remove
+        with self.assertWarnsRegex(DeprecationWarning,
+                r"^Assigning value with shape .* to value with shape .* will become an error in Amaranth 0.7$"):
             s.eq(s2)

tests/test_lib_wiring.py

@@ -860,9 +860,12 @@ class FirstDelimited(data.Struct):
             first: 1
 
         m = Module()
-        with self.assertRaisesRegex(ConnectionError,
-                r"^Cannot connect input member 'q\.a' to output member 'p\.a' because assignment "
-                r"failed$"):
+        #with self.assertRaisesRegex(ConnectionError,
+        #        r"^Cannot connect input member 'q\.a' to output member 'p\.a' because assignment "
+        #        r"failed$"):
+        # TODO(amaranth-0.7): remove
+        with self.assertWarnsRegex(DeprecationWarning,
+                r"^Assigning value with shape .* to view with layout .* will become an error in Amaranth 0.7$"):
             connect(m,
                     p=NS(signature=Signature({"a": Out(LastDelimited)}),
                          a=Signal(LastDelimited)),