From eb72ef050d94dd32cbb1499243af5de4e9eec22c Mon Sep 17 00:00:00 2001
From: Dima Pasechnik <dima@pasechnik.info>
Date: Tue, 29 Nov 2022 21:06:01 +0000
Subject: [PATCH] avoid is_GapElement

---
 src/sage/rings/finite_rings/element_givaro.pyx     |  8 ++++++--
 src/sage/rings/finite_rings/element_ntl_gf2e.pyx   | 10 +++++++---
 src/sage/rings/finite_rings/element_pari_ffelt.pyx |  8 ++++++--
 src/sage/rings/finite_rings/integer_mod_ring.py    | 13 +++++++++++--
 4 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/src/sage/rings/finite_rings/element_givaro.pyx b/src/sage/rings/finite_rings/element_givaro.pyx
index 42f93cceb75..790121a62dc 100644
--- a/src/sage/rings/finite_rings/element_givaro.pyx
+++ b/src/sage/rings/finite_rings/element_givaro.pyx
@@ -72,7 +72,11 @@ from cypari2.stack cimport clear_stack
 
 from sage.structure.parent cimport Parent
 
-from sage.interfaces.gap import is_GapElement
+
+try:
+    from sage.interfaces.gap import GapElement
+except ImportError:
+    GapElement = ()
 
 cdef object is_IntegerMod
 cdef object Integer
@@ -435,7 +439,7 @@ cdef class Cache_givaro(Cache_base):
         elif isinstance(e, sage.libs.gap.element.GapElement_FiniteField):
             return e.sage(ring=self.parent)
 
-        elif is_GapElement(e):
+        elif isinstance(e, GapElement):
             from sage.libs.gap.libgap import libgap
             return libgap(e).sage(ring=self.parent)
 
diff --git a/src/sage/rings/finite_rings/element_ntl_gf2e.pyx b/src/sage/rings/finite_rings/element_ntl_gf2e.pyx
index ebe16dcdcd8..fefd492f952 100644
--- a/src/sage/rings/finite_rings/element_ntl_gf2e.pyx
+++ b/src/sage/rings/finite_rings/element_ntl_gf2e.pyx
@@ -52,11 +52,15 @@ from sage.arith.long cimport pyobject_to_long
 from .element_pari_ffelt import FiniteFieldElement_pari_ffelt
 from .finite_field_ntl_gf2e import FiniteField_ntl_gf2e
 
+from sage.rings.polynomial.polynomial_ring_constructor import PolynomialRing
+
 from sage.libs.gap.element import GapElement_FiniteField
 
-from sage.interfaces.gap import is_GapElement
+try:
+    from sage.interfaces.gap import GapElement
+except ImportError:
+    GapElement = ()
 
-from sage.rings.polynomial.polynomial_ring_constructor import PolynomialRing
 
 cdef object is_IntegerMod
 cdef object IntegerModRing_generic
@@ -369,7 +373,7 @@ cdef class Cache_ntl_gf2e(Cache_base):
         elif isinstance(e, GapElement_FiniteField):
             return e.sage(ring=self._parent)
 
-        elif is_GapElement(e):
+        elif isinstance(e, GapElement):
             from sage.libs.gap.libgap import libgap
             return libgap(e).sage(ring=self._parent)
 
diff --git a/src/sage/rings/finite_rings/element_pari_ffelt.pyx b/src/sage/rings/finite_rings/element_pari_ffelt.pyx
index 0ee972a7b61..d427f1a5282 100644
--- a/src/sage/rings/finite_rings/element_pari_ffelt.pyx
+++ b/src/sage/rings/finite_rings/element_pari_ffelt.pyx
@@ -29,7 +29,6 @@ from .element_base cimport FinitePolyExtElement
 from .integer_mod import IntegerMod_abstract
 
 import sage.rings.integer
-from sage.interfaces.gap import is_GapElement
 from sage.modules.free_module_element import FreeModuleElement
 from sage.rings.integer cimport Integer
 from sage.rings.polynomial.polynomial_element import Polynomial
@@ -39,6 +38,11 @@ from sage.structure.element cimport Element, ModuleElement, RingElement
 from sage.structure.richcmp cimport rich_to_bool
 
 
+try:
+    from sage.interfaces.gap import GapElement
+except ImportError:
+    GapElement = ()
+
 cdef GEN _INT_to_FFELT(GEN g, GEN x) except NULL:
     """
     Convert the t_INT `x` to an element of the field of definition of
@@ -504,7 +508,7 @@ cdef class FiniteFieldElement_pari_ffelt(FinitePolyExtElement):
         elif isinstance(x, str):
             self.construct_from(self._parent.polynomial_ring()(x))
 
-        elif is_GapElement(x):
+        elif isinstance(x, GapElement):
             try:
                 from sage.libs.gap.libgap import libgap
                 self.construct_from(libgap(x).sage(ring=self._parent))
diff --git a/src/sage/rings/finite_rings/integer_mod_ring.py b/src/sage/rings/finite_rings/integer_mod_ring.py
index 7049f2d6b11..01eab795111 100644
--- a/src/sage/rings/finite_rings/integer_mod_ring.py
+++ b/src/sage/rings/finite_rings/integer_mod_ring.py
@@ -77,7 +77,10 @@
 from sage.structure.factory import UniqueFactory
 from sage.structure.richcmp import richcmp, richcmp_method
 
-from sage.interfaces.gap import is_GapElement
+try:
+    from sage.interfaces.gap import GapElement
+except ImportError:
+    GapElement = ()
 
 class IntegerModFactory(UniqueFactory):
     r"""
@@ -1180,13 +1183,19 @@ def _element_constructor_(self, x):
             4
             sage: libgap(a.sage()) == a
             True
+
+        better syntax for libgap interface::
+
+            sage: a = libgap.Z(13)^2
+            sage: libgap(a.sage()) == a
+            True
         """
         try:
             return integer_mod.IntegerMod(self, x)
         except (NotImplementedError, PariError):
             raise TypeError("error coercing to finite field")
         except TypeError:
-            if is_GapElement(x):
+            if isinstance(x, GapElement):
                 from sage.libs.gap.libgap import libgap
                 return libgap(x).sage()
             raise  # Continue up with the original TypeError