concrete: stop doit() in _eval_factor() helper

Closes sympy/sympy#24346

diofant/concrete/expr_with_limits.py

@@ -407,7 +407,9 @@ def _eval_factor(self, **hints):
         else:
             summand = self.func(self.function, self.limits[0:-1]).factor()
             if not summand.has(self.variables[-1]):
-                return self.func(1, [self.limits[-1]]).doit()*summand
+                return self.func(1, [self.limits[-1]])*summand
+            elif isinstance(summand, Mul):
+                return self.func(summand, self.limits[-1]).factor()
         return self
 
     def _eval_expand_basic(self, **hints):

diofant/tests/polys/test_polytools.py

@@ -2365,6 +2365,13 @@ def test_factor():
     assert (2*Sum(3*x, (x, 1, 9))).factor() == 6*Sum(x, (x, 1, 9))
     assert (2*Sum(x**2, (x, 1, 9))).factor() == 2*Sum(x**2, (x, 1, 9))
 
+    # issue sympy/sympy#24346
+    i = Integral(2*x, x, y)
+    assert factor(i) == 2*Integral(x, x)*Integral(1, y)
+    assert factor(1 + i) == 1 + i
+    i2 = Integral(2*x*y, x, y)
+    assert factor(i2) == 2*Integral(x, x)*Integral(y, y)
+
     A, B = symbols('A B', commutative=False)
     f = (x - A)*(y - B)
     assert factor(f.expand()) == f

docs/release/notes-0.14.rst

@@ -103,3 +103,4 @@ These Sympy issues also were addressed:
 * :sympyissue:`24210`: Error on limits regarding terms like (1+u)^v.
 * :sympyissue:`24225`: Multivariable limit should be undefined, but gives unity.
 * :sympyissue:`24266`: Changed behaviour of series() involving exp, I
+* :sympyissue:`24346`: factor with extension=True fails for rational expression