Ticket #13184: trac_13184_sage_5.5.0.beta.patch

sage/categories/homset.py

@@ -154 +154 @@
 
     TESTS:
 
-    Some doc tests in :mod:`sage.rings` (need to) break the unique parent assumption.
-    But if domain or codomain are not unique parents, then the hom set won't fit.
-    That's to say, the hom set found in the cache will have a (co)domain that is
+    Homset are unique parents::
+
+        sage: k = GF(5)
+        sage: H1 = Hom(k,k)
+        sage: H2 = Hom(k,k)
+        sage: H1 is H2
+        True
+
+    However, some doc tests in :mod:`sage.rings` (need to) break the unique parent 
+    assumption. If domain or codomain are not unique parents, then the hom set won't 
+    fit. That's to say, the hom set found in the cache will have a (co)domain that is
     equal to, but not identic with, the given (co)domain.
 
     By trac ticket #9138, we abandon the uniqueness of hom sets, if the domain or
@@ -222 +230 @@
 
     try:
         # Apparently X._Hom_ is supposed to be cached
-        return X._Hom_(Y, category)
+        # but it is not in some cases (e.g. X is a finite field)
+        # To be investigated
+        H = X._Hom_(Y,category) 
+        _cache[key] = weakref.ref(H) 
+        return H 
     except (AttributeError, TypeError):
         pass