Check effective divisor degree depending on the model

Author: kwankyu

src/sage/rings/function_field/jacobian_base.py

@@ -668,7 +668,7 @@ def __call__(self, x):
         if x in F.divisor_group():
             G = self.group()
             return G.point(x)
-        raise ValueError(f"Cannot create a point of the Jacobian from {x}")
+        raise ValueError(f"cannot create a point of the Jacobian from {x}")
 
     def curve(self):
         """

src/sage/rings/function_field/jacobian_hess.py

@@ -606,7 +606,7 @@ def _element_constructor_(self, x):
         """
         Construct an element of ``self`` from ``x``.
 
-        If ``x`` is an effective divisor, then it is assumed to of
+        If ``x`` is an effective divisor, then it is assumed to be of
         degree `g`, the genus of the function field.
 
         EXAMPLES::
@@ -634,9 +634,11 @@ def _element_constructor_(self, x):
             if x.degree() == 0:
                 return self.point(x)
             if x.is_effective():
+                if x.degree() != self._genus:
+                    raise ValueError(f"effective divisor is not of degree {self._genus}")
                 return self.element_class(self, *self._get_dS_ds(x))
 
-        raise ValueError(f"Cannot construct a point from {x}")
+        raise ValueError(f"cannot construct a point from {x}")
 
     def _get_dS_ds(self, divisor):
         """
@@ -805,6 +807,8 @@ def point(self, divisor):
             sage: G.point(p - b)
             [Place (y + 2, z + 1)]
         """
+        if divisor.degree() != 0:
+            raise ValueError('divisor not of degree zero')
         c = divisor + self._base_div
         f = c.basis_function_space()[0]
         d = f.divisor() + c

src/sage/rings/function_field/jacobian_khuri_makdisi.py

@@ -619,6 +619,7 @@ def __init__(self, parent, function_field, base_div):
 
         D0 = base_div
 
+        self._base_div_degree = base_div.degree()
         self._V_cache = 10*[None]
 
         V_cache = self._V_cache
@@ -760,10 +761,12 @@ def _element_constructor_(self, x):
             if x.degree() == 0:
                 return self.point(x)
             if x.is_effective():
+                if x.degree() != self._base_div_degree:
+                    raise ValueError(f"effective divisor is not of degree {self._base_div_degree}")
                 wd = self._wd_from_divisor(x)
                 return self.element_class(self, wd)
 
-        raise ValueError(f"Cannot construct a point from {x}")
+        raise ValueError(f"cannot construct a point from {x}")
 
     def point(self, divisor):
         """