Fixed #28730 -- Fixed loss of precision for large integer literals in templates

Thanks Fraser Nevett for the report and Tim Graham for patch edits.

django/template/base.py

@@ -762,17 +762,16 @@ class Variable:
             # Note that this could cause an OverflowError here that we're not
             # catching. Since this should only happen at compile time, that's
             # probably OK.
-            self.literal = float(var)
-
-            # So it's a float... is it an int? If the original value contained a
-            # dot or an "e" then it was a float, not an int.
-            if '.' not in var and 'e' not in var.lower():
-                self.literal = int(self.literal)
-
-            # "2." is invalid
-            if var.endswith('.'):
-                raise ValueError
 
+            # Try to interpret values containg a period or an 'e'/'E'
+            # (possibly scientific notation) as a float;  otherwise, try int.
+            if '.' in var or 'e' in var.lower():
+                self.literal = float(var)
+                # "2." is invalid
+                if var.endswith('.'):
+                    raise ValueError
+            else:
+                self.literal = int(var)
         except ValueError:
             # A ValueError means that the variable isn't a number.
             if var.startswith('_(') and var.endswith(')'):

tests/template_tests/test_base.py

@@ -1,4 +1,4 @@
-from django.template.base import VariableDoesNotExist
+from django.template.base import Variable, VariableDoesNotExist
 from django.test import SimpleTestCase
 
 
@@ -6,3 +6,8 @@ class VariableDoesNotExistTests(SimpleTestCase):
     def test_str(self):
         exc = VariableDoesNotExist(msg='Failed lookup in %r', params=({'foo': 'bar'},))
         self.assertEqual(str(exc), "Failed lookup in {'foo': 'bar'}")
+
+
+class VariableTests(SimpleTestCase):
+    def test_integer_literals(self):
+        self.assertEqual(Variable('999999999999999999999999999').literal, 999999999999999999999999999)