Merge pull request LMFDB#7129 from roed-math/fix-cm-field-mixed-types

Fix 500 on CM elliptic curve isogeny class pages

Author: roed314

lmfdb/elliptic_curves/isog_class.py

@@ -175,7 +175,9 @@ def perm(i): return next(c for c in self.curves if c['Cnumber'] == i+1)['lmfdb_n
         if self.cm:
             # set CM field for Properties box.
             D = integer_squarefree_part(ZZ(self.cm))
-            coeffs = [(1-D)//4,-1,1] if D % 4 == 1 else [-D,0,1]
+            # int() everything so that the query list is not a mix of Sage Integers
+            # and Python ints, which psycopg cannot adapt
+            coeffs = [int((1-D)//4),-1,1] if D % 4 == 1 else [int(-D),0,1]
             lab = db.nf_fields.lucky({'coeffs': coeffs}, projection='label')
             self.CMfield = field_pretty(lab)
         else:

lmfdb/elliptic_curves/test_ell_curves.py

@@ -126,6 +126,16 @@ def test_isogeny_class(self):
         L = self.tc.get('/EllipticCurve/Q/11/a/')
         assert '[0, -1, 1, 0, 0]' in L.get_data(as_text=True)
 
+    def test_cm_isogeny_class(self):
+        # The CM field shown in the Properties box is looked up in nf_fields
+        # by coefficient list; this 500ed when that list mixed Sage Integers
+        # with Python ints (see #7129).  27.a and 32.a exercise the two
+        # branches computing the coefficient list.
+        L = self.tc.get('/EllipticCurve/Q/27/a/')
+        assert r'\Q(\sqrt{-3})' in L.get_data(as_text=True)
+        L = self.tc.get('/EllipticCurve/Q/32/a/')
+        assert r'\Q(\sqrt{-1})' in L.get_data(as_text=True)
+
     def test_dl_qexp(self):
         L = self.tc.get('/EllipticCurve/Q/download_qexp/66.c3/100')
         assert '0,1,1,1,1,-4,1,-2,1,1,-4,1,1,4,-2,-4,1,-2,1,0,-4,-2,1,-6,1,11,4,1,-2,10,-4,-8,1,1,-2,8,1,-2,0,4,-4,2,-2,4,1,-4,-6,-2,1,-3,11,-2,4,4,1,-4,-2,0,10,0,-4,-8,-8,-2,1,-16,1,-12,-2,-6,8,2,1,-6,-2,11,0,-2,4,10,-4,1,2,4,-2,8,4,10,1,10,-4,-8,-6,-8,-2,0,1,-2,-3,1,11' in L.get_data(as_text=True)