Changed warning message to leaner version.

src/doc/en/reference/coercion/index.rst

@@ -275,13 +275,10 @@ references to the domain. Such maps should only be used internally, and so a
 copy should be used instead (unless one knows what one is doing)::
 
     sage: QQ._internal_coerce_map_from(int)
+    (map internal to coercion system -- copy before use)
     Native morphism:
       From: Set of Python objects of type 'int'
       To:   Rational Field
-    <BLANKLINE>
-            WARNING: This morphism has apparently been used internally
-            in the coercion system. It may become defunct in the next
-            garbage collection. Please use a copy.
     sage: copy(QQ._internal_coerce_map_from(int))
     Native morphism:
      From: Set of Python objects of type 'int'

src/sage/categories/homset.py

@@ -607,24 +607,18 @@ def _generic_convert_map(self, S):
               Defn:   Composite map:
                       From: Integer Ring
                       To:   Univariate Polynomial Ring in t over Integer Ring
-                      Defn:   Polynomial base injection morphism:
+                      Defn:   (map internal to coercion system -- copy before use)
+                            Polynomial base injection morphism:
                               From: Integer Ring
                               To:   Univariate Polynomial Ring in t over Integer Ring
-            <BLANKLINE>
-                                    WARNING: This morphism has apparently been used internally
-                                    in the coercion system. It may become defunct in the next
-                                    garbage collection. Please use a copy.
                             then
                               Ring endomorphism of Univariate Polynomial Ring in t over Integer Ring
                               Defn: t |--> 2*t
                     then
-                      Ring morphism:
+                      (map internal to coercion system -- copy before use)
+                    Ring morphism:
                       From: Univariate Polynomial Ring in t over Integer Ring
                       To:   Univariate Polynomial Ring in t over Rational Field
-            <BLANKLINE>
-                            WARNING: This morphism has apparently been used internally
-                            in the coercion system. It may become defunct in the next
-                            garbage collection. Please use a copy.
             sage: copy(H._generic_convert_map(f.parent())(f))
             Composite map:
               From: Integer Ring
@@ -694,25 +688,19 @@ def __call__(self, x=None, y=None, check=True, **options):
               Defn:   Composite map:
                       From: Symmetric group of order 4! as a permutation group
                       To:   Symmetric group of order 6! as a permutation group
-                      Defn:   Call morphism:
+                      Defn:   (map internal to coercion system -- copy before use)
+                            Call morphism:
                               From: Symmetric group of order 4! as a permutation group
                               To:   Symmetric group of order 5! as a permutation group
-            <BLANKLINE>
-                                    WARNING: This morphism has apparently been used internally
-                                    in the coercion system. It may become defunct in the next
-                                    garbage collection. Please use a copy.
                             then
                               Coercion morphism:
                               From: Symmetric group of order 5! as a permutation group
                               To:   Symmetric group of order 6! as a permutation group
                     then
-                      Call morphism:
+                      (map internal to coercion system -- copy before use)
+                    Call morphism:
                       From: Symmetric group of order 6! as a permutation group
                       To:   Symmetric group of order 7! as a permutation group
-            <BLANKLINE>
-                            WARNING: This morphism has apparently been used internally
-                            in the coercion system. It may become defunct in the next
-                            garbage collection. Please use a copy.
 
       Also note that making a copy of the resulting map will automatically
       make strengthened copies of the composed maps::

src/sage/categories/map.pyx

@@ -549,14 +549,11 @@ cdef class Map(Element):
         TESTS::
 
             sage: Q = QuadraticField(-5)
-            sage: phi = CDF._internal_coerce_map_from(Q); phi   # indirect doctest
+            sage: phi = CDF._internal_coerce_map_from(Q); phi
+            (map internal to coercion system -- copy before use)
             Composite map:
               From: Number Field in a with defining polynomial x^2 + 5
               To:   Complex Double Field
-            <BLANKLINE>
-                    WARNING: This map has apparently been used internally
-                    in the coercion system. It may become defunct in the next
-                    garbage collection. Please use a copy.
             sage: del Q
             sage: import gc
             sage: _ = gc.collect()
@@ -574,11 +571,8 @@ cdef class Map(Element):
             if d != '':
                 s += "\n  Defn: %s"%('\n        '.join(d.split('\n')))
         else:
-            d = """
-WARNING: This map has apparently been used internally
-in the coercion system. It may become defunct in the next
-garbage collection. Please use a copy."""
-            s += "\n%s"%('\n        '.join(d.split('\n')))
+            d = "(map internal to coercion system -- copy before use)"
+            s = d + "\n" + s
         return s
 
     def _default_repr_(self):

src/sage/categories/modules_with_basis.py

@@ -1729,9 +1729,7 @@ def section(self):
             sage: phiinv(Y.basis()[1])
             Traceback (most recent call last):
             ...
-            ValueError: B[1] is not in the image of Generic morphism:
-              From: X
-              To:   Free module generated by {1, 2, 3, 4, 5} over Rational Field
+            ValueError: B[1] is not in the image
         """
         if self._inverse is not None:
             return self._inverse
@@ -1810,18 +1808,13 @@ def preimage(self, f):
             sage: phi.preimage(y[1])
             Traceback (most recent call last):
             ...
-            ValueError: B[1] is not in the image of Generic morphism:
-              From: X
-              To:   Free module generated by {1, 2, 3, 4, 5} over Rational Field
+            ValueError: B[1] is not in the image
         """
         F = self.domain()
         G = self.codomain()
         basis_map = self._on_basis
         if not f in G:
-            # We make a copy of self in case self is an internal coercion morphism
-            #   because we don't want the WARNING message to be displayed
-            from copy import copy
-            raise ValueError("f(={}) must be in the codomain of the morphism (={}) to have a preimage under the latter".format(f, copy(self)))
+            raise ValueError("f(={}) must be in the codomain of the morphism to have a preimage under the latter".format(f))
 
         remainder = f
 
@@ -1834,9 +1827,7 @@ def preimage(self, f):
             else:
                 j_preimage = self._inverse_on_support(j)
                 if j_preimage is None:
-                    # Make a copy of self for the same reason as before
-                    from copy import copy
-                    raise ValueError("{} is not in the image of {}".format(f, copy(self)))
+                    raise ValueError("{} is not in the image".format(f))
             s = basis_map(j_preimage)
             if not j == self._dominant_item(s)[0]:
                 raise ValueError("The morphism (={}) is not triangular at {}, and therefore a preimage cannot be computed".format(f, s))

src/sage/categories/morphism.pyx

@@ -77,13 +77,10 @@ cdef class Morphism(Map):
             sage: K = CyclotomicField(12)
             sage: L = CyclotomicField(132)
             sage: phi = L._internal_coerce_map_from(K); phi
+            (map internal to coercion system -- copy before use)
             Generic morphism:
               From: Cyclotomic Field of order 12 and degree 4
               To:   Cyclotomic Field of order 132 and degree 40
-            <BLANKLINE>
-                    WARNING: This morphism has apparently been used internally
-                    in the coercion system. It may become defunct in the next
-                    garbage collection. Please use a copy.
 
             sage: del K
             sage: import gc
@@ -105,11 +102,8 @@ cdef class Morphism(Map):
             if d != '':
                 s += "\n  Defn: " + '\n        '.join(d.split('\n'))
         else:
-            d = """
-WARNING: This morphism has apparently been used internally
-in the coercion system. It may become defunct in the next
-garbage collection. Please use a copy."""
-            s += "\n" + '\n        '.join(d.split('\n'))
+            d = "(map internal to coercion system -- copy before use)"
+            s = d + "\n" + s
         return s
 
     def _default_repr_(self):

src/sage/combinat/ncsym/dual.py

@@ -407,9 +407,7 @@ def _set_par_to_par(self, A):
                 sage: h(w[[1,3],[2]])
                 Traceback (most recent call last):
                 ...
-                ValueError: w{{1, 3}, {2}} is not in the image of Generic morphism:
-                  From: Symmetric Functions over Rational Field in the homogeneous basis
-                  To:   Dual symmetric functions in non-commuting variables over the Rational Field in the w basis
+                ValueError: w{{1, 3}, {2}} is not in the image
                 sage: h(w(h[2,1])) == w(h[2,1]).to_symmetric_function()
                 True
             """

src/sage/combinat/sf/new_kschur.py

@@ -148,9 +148,7 @@ def retract(self, sym):
             sage: KB.retract(s[2,1,1])
             Traceback (most recent call last):
             ...
-            ValueError: s[2, 1, 1] is not in the image of Generic morphism:
-              From: 3-bounded Symmetric Functions over Rational Field with t=1 in the 3-Schur basis also with t=1
-              To:   Symmetric Functions over Rational Field in the Schur basis
+            ValueError: s[2, 1, 1] is not in the image
         """
         s = self.ambient().schur()
         ks = self.kschur()
@@ -606,9 +604,7 @@ def _mul_(self, other):
                 sage: ks(f)
                 Traceback (most recent call last):
                 ...
-                ValueError: s[3, 2, 1] + s[3, 3] + s[4, 1, 1] + (t+1)*s[4, 2] + (t+1)*s[5, 1] + t*s[6] is not in the image of Generic morphism:
-                  From: 3-bounded Symmetric Functions over Univariate Polynomial Ring in t over Rational Field in the 3-Schur basis
-                  To:   Symmetric Functions over Univariate Polynomial Ring in t over Rational Field in the Schur basis
+                ValueError: s[3, 2, 1] + s[3, 3] + s[4, 1, 1] + (t+1)*s[4, 2] + (t+1)*s[5, 1] + t*s[6] is not in the image
                 sage: Sym = SymmetricFunctions(QQ)
                 sage: ks = Sym.kschur(3,1)
                 sage: f = ks[2]*ks[3,1]; f
@@ -714,9 +710,7 @@ def omega(self):
                 sage: ks[3,1,1].omega()
                 Traceback (most recent call last):
                 ...
-                ValueError: t*s[2, 1, 1, 1] + s[3, 1, 1] is not in the image of Generic morphism:
-                From: 3-bounded Symmetric Functions over Fraction Field of Univariate Polynomial Ring in t over Rational Field in the 3-Schur basis
-                To:   Symmetric Functions over Fraction Field of Univariate Polynomial Ring in t over Rational Field in the Schur basis
+                ValueError: t*s[2, 1, 1, 1] + s[3, 1, 1] is not in the image
             """
             return self.parent()(self.lift().omega())
 
@@ -886,9 +880,7 @@ class kSchur(CombinatorialFreeModule):
         sage: ks3(s([4]))
         Traceback (most recent call last):
         ...
-        ValueError: s[4] is not in the image of Generic morphism:
-          From: 3-bounded Symmetric Functions over Univariate Polynomial Ring in t over Rational Field in the 3-Schur basis
-          To:   Symmetric Functions over Univariate Polynomial Ring in t over Rational Field in the Schur basis
+        ValueError: s[4] is not in the image
 
     Note that the product of `k`-Schur functions is not guaranteed to be in the
     space spanned by the `k`-Schurs. In general, we only have that a

src/sage/combinat/sf/sf.py

@@ -590,9 +590,7 @@ class function on the symmetric group where the elements
         sage: ks(s[2,1,1])
         Traceback (most recent call last):
         ...
-        ValueError: s[2, 1, 1] is not in the image of Generic morphism:
-          From: 3-bounded Symmetric Functions over Rational Field with t=1 in the 3-Schur basis also with t=1
-          To:   Symmetric Functions over Rational Field in the Schur basis
+        ValueError: s[2, 1, 1] is not in the image
 
     The `k`-Schur functions are more generally defined with a parameter `t` and they are
     a basis of the subspace spanned by the Hall-Littlewood ``Qp`` symmetric functions
@@ -613,9 +611,7 @@ class function on the symmetric group where the elements
         sage: ks(ks[2,1]*ks[1,1])
         Traceback (most recent call last):
         ...
-        ValueError: s[2, 1, 1, 1] + s[2, 2, 1] + s[3, 1, 1] + s[3, 2] is not in the image of Generic morphism:
-          From: 3-bounded Symmetric Functions over Fraction Field of Univariate Polynomial Ring in t over Rational Field in the 3-Schur basis
-          To:   Symmetric Functions over Fraction Field of Univariate Polynomial Ring in t over Rational Field in the Schur basis
+        ValueError: s[2, 1, 1, 1] + s[2, 2, 1] + s[3, 1, 1] + s[3, 2] is not in the image
         sage: ks[2,1]*ks[1,1]
         s[2, 1, 1, 1] + s[2, 2, 1] + s[3, 1, 1] + s[3, 2]
         sage: ks6 = Sym.kBoundedSubspace(6).kschur()

src/sage/structure/coerce.pyx

@@ -1021,21 +1021,15 @@ cdef class CoercionModel_cache_maps(CoercionModel):
 
             sage: f, g = cm.coercion_maps(ZZ['x'], QQ)
             sage: print f
+            (map internal to coercion system -- copy before use)
             Ring morphism:
               From: Univariate Polynomial Ring in x over Integer Ring
               To:   Univariate Polynomial Ring in x over Rational Field
-            <BLANKLINE>
-                    WARNING: This morphism has apparently been used internally
-                    in the coercion system. It may become defunct in the next
-                    garbage collection. Please use a copy.
             sage: print g
+            (map internal to coercion system -- copy before use)
             Polynomial base injection morphism:
               From: Rational Field
               To:   Univariate Polynomial Ring in x over Rational Field
-            <BLANKLINE>
-                    WARNING: This morphism has apparently been used internally
-                    in the coercion system. It may become defunct in the next
-                    garbage collection. Please use a copy.
 
             sage: cm.coercion_maps(QQ, GF(7)) == None
             True
@@ -1051,23 +1045,15 @@ cdef class CoercionModel_cache_maps(CoercionModel):
             False
             sage: cm = sage.structure.element.get_coercion_model()
             sage: cm.coercion_maps(V, W)
-            (None,
-             Call morphism:
+            (None, (map internal to coercion system -- copy before use)
+            Call morphism:
               From: Vector space of dimension 3 over Rational Field
-              To:   Vector space of dimension 3 over Rational Field
-            <BLANKLINE>
-                    WARNING: This morphism has apparently been used internally
-                    in the coercion system. It may become defunct in the next
-                    garbage collection. Please use a copy.)
+              To:   Vector space of dimension 3 over Rational Field)
             sage: cm.coercion_maps(W, V)
-            (None,
-             Call morphism:
+            (None, (map internal to coercion system -- copy before use)
+            Call morphism:
               From: Vector space of dimension 3 over Rational Field
-              To:   Vector space of dimension 3 over Rational Field
-            <BLANKLINE>
-                    WARNING: This morphism has apparently been used internally
-                    in the coercion system. It may become defunct in the next
-                    garbage collection. Please use a copy.)
+              To:   Vector space of dimension 3 over Rational Field)
             sage: v = V([1,2,3])
             sage: w = W([1,2,3])
             sage: parent(v+w) is V
@@ -1187,9 +1173,10 @@ cdef class CoercionModel_cache_maps(CoercionModel):
         If there is a coercion map either direction, use that::
 
             sage: cm.discover_coercion(ZZ, QQ)
-            (Natural morphism:
+            ((map internal to coercion system -- copy before use)
+            Natural morphism:
               From: Integer Ring
-              To:   Rational Field..., None)
+              To:   Rational Field, None)
             sage: cm.discover_coercion(RR, QQ)
             (None,
              Generic map:
@@ -1199,12 +1186,13 @@ cdef class CoercionModel_cache_maps(CoercionModel):
         Otherwise, try and compute an appropriate cover::
 
             sage: cm.discover_coercion(ZZ['x,y'], RDF)
-            (Call morphism:
+            ((map internal to coercion system -- copy before use)
+            Call morphism:
               From: Multivariate Polynomial Ring in x, y over Integer Ring
-              To:   Multivariate Polynomial Ring in x, y over Real Double Field...,
+              To:   Multivariate Polynomial Ring in x, y over Real Double Field,
              Polynomial base injection morphism:
               From: Real Double Field
-              To:   Multivariate Polynomial Ring in x, y over Real Double Field...)
+              To:   Multivariate Polynomial Ring in x, y over Real Double Field)
 
         Sometimes there is a reasonable "cover," but no canonical coercion::