Trac #32860: Inaccurate documentation for number field elements_of_norm

For a number field `K` and an integer `n`,
the function `K.elements_of_norm(n)` returns
a list of integral elements of `K` with norm `n`,
up to multiplication by units of positive norm.
The docstring says that `n` should be an "integer
in this number field", which is wrong (and makes
no sense): it must be a rational integer.

If you give the function something else (e.g. a
non-integral rational or an element of `K` (even
`K(0)`), a `PariError` is raised, and it would be
better for Sage to check the input, say by trying
`n = ZZ(n)` first.

URL: https://trac.sagemath.org/32860
Reported by: cremona
Ticket author(s): Frédéric Chapoton
Reviewer(s): John Cremona

Author: Release Manager

build/pkgs/configure/checksums.ini

@@ -1,4 +1,4 @@
 tarball=configure-VERSION.tar.gz
-sha1=ddc95e8bbd9b0a04576bf0040cb6e9a3743a7025
-md5=b6062b6b285211a65a7b005eac230ff4
-cksum=3715468583
+sha1=63a185e63945337d9e35c8befb0842a338f8d485
+md5=d1ad922ab9d630f1f3d05ea2cd265a0d
+cksum=727308674

build/pkgs/configure/package-version.txt

@@ -1 +1 @@
-3e2eba8dba557a9626a3c465206b89776f3ebeac
+866a2b24b7ffc1f489c181243c6b90659f79e741

src/sage/rings/number_field/number_field.py

@@ -104,7 +104,7 @@
 #  the License, or (at your option) any later version.
 #                  https://www.gnu.org/licenses/
 # ****************************************************************************
-
+from __future__ import annotations
 from sage.misc.cachefunc import cached_method
 from sage.misc.superseded import (deprecation,
                                   deprecated_function_alias)
@@ -5726,13 +5726,13 @@ def trace_dual_basis(self, b):
             raise ValueError('Not a basis of the number field.')
         return [sum([v[i]*b[i] for i in range(len(b))]) for v in M.inverse()]
 
-    def elements_of_norm(self, n, proof=None):
+    def elements_of_norm(self, n, proof=None) -> list:
         """
-        Return a list of elements of norm ``n``.
+        Return a list of elements of norm `n`.
 
         INPUT:
 
-        - ``n`` -- integer in this number field
+        - `n` -- integer
 
         - ``proof`` -- boolean (default: ``True``, unless you called
           :meth:`proof.number_field` and set it otherwise)
@@ -5761,6 +5761,7 @@ def elements_of_norm(self, n, proof=None):
             sage: x in (7/225*a^2 - 7/75*a - 42/25, 28/225*a^2 + 77/75*a - 133/25)
             True
         """
+        n = ZZ(n)
         proof = proof_flag(proof)
         B = self.pari_bnf(proof).bnfisintnorm(n)
         return [self(x, check=False) for x in B]