Fix Constant numbering

.github/workflows/build.yml

@@ -79,6 +79,7 @@ jobs:
             --install icepack \
             --install irksome \
             --install femlium \
+            --package-branch ufl connorjward/counted-mixin2 \
             || (cat firedrake-install.log && /bin/false)
       - name: Install test dependencies
         run: |

firedrake/constant.py

@@ -6,7 +6,7 @@
 from pyop2.exceptions import DataTypeError, DataValueError
 from firedrake.petsc import PETSc
 from firedrake.utils import ScalarType
-from ufl.utils.counted import counted_init
+from ufl.utils.counted import Counted
 
 
 import firedrake.utils as utils
@@ -30,7 +30,7 @@ def _create_dat(op2type, value, comm):
     return dat, rank, shape
 
 
-class Constant(ufl.constantvalue.ConstantValue, ConstantMixin, TSFCConstantMixin):
+class Constant(ufl.constantvalue.ConstantValue, ConstantMixin, TSFCConstantMixin, Counted):
     """A "constant" coefficient
 
     A :class:`Constant` takes one value over the whole
@@ -53,9 +53,8 @@ class Constant(ufl.constantvalue.ConstantValue, ConstantMixin, TSFCConstantMixin
        :class:`~ufl.form.Form` on its own you need to pass a
        :func:`~.Mesh` as the domain argument.
     """
-    _globalcount = 0
 
-    def __new__(cls, value, domain=None):
+    def __new__(cls, value, domain=None, name=None, count=None):
         if domain:
             # Avoid circular import
             from firedrake.function import Function
@@ -83,7 +82,7 @@ def __new__(cls, value, domain=None):
             return object.__new__(cls)
 
     @ConstantMixin._ad_annotate_init
-    def __init__(self, value, domain=None, name=None):
+    def __init__(self, value, domain=None, name=None, count=None):
         # Init also called in mesh constructor, but constant can be built without mesh
         utils._init()
 
@@ -93,12 +92,20 @@ def __init__(self, value, domain=None, name=None):
         self.name = name or 'constant_%d' % self.uid
 
         super().__init__()
-        counted_init(self, None, self.__class__)
-        self._hash = None
+        Counted.__init__(self, count)
 
     def __repr__(self):
         return f"Constant({self.dat.data_ro}, {self.count()})"
 
+    def _ufl_signature_data_(self, renumbering):
+        return (type(self).__name__, renumbering[self])
+
+    def __hash__(self):
+        return hash((type(self), self.count()))
+
+    def __eq__(self, other):
+        return type(self) == type(other) and self.count() == other.count()
+
     @property
     def ufl_shape(self):
         return self._ufl_shape

firedrake/interpolation.py

@@ -644,4 +644,7 @@ def hash_expr(expr):
     """
     domain_numbering = {d: i for i, d in enumerate(ufl.domain.extract_domains(expr))}
     coefficient_numbering = {c: i for i, c in enumerate(extract_coefficients(expr))}
-    return compute_expression_signature(expr, {**domain_numbering, **coefficient_numbering})
+    constant_numbering = {c: i for i, c in enumerate(extract_firedrake_constants(expr))}
+    return compute_expression_signature(
+        expr, {**domain_numbering, **coefficient_numbering, **constant_numbering}
+    )

tests/regression/test_constant.py

@@ -174,3 +174,12 @@ def test_fresh_constant_hashes_different():
     d = Constant(1)
 
     assert hash(c) != hash(d)
+
+
+def test_constants_are_renumbered_in_form_signature():
+    mesh = UnitSquareMesh(1, 1)
+    c = Constant(1)
+    d = Constant(1)
+
+    assert c.count() != d.count()
+    assert (c*dx(domain=mesh)).signature() == (d*dx(domain=mesh)).signature()