Fixed #23913 -- Deprecated the = comparison in if template tag.

django/template/defaulttags.py

@@ -999,7 +999,7 @@ def do_if(parser, token):
     ``{% if 1>2 %}`` is not a valid if tag.
 
     All supported operators are: ``or``, ``and``, ``in``, ``not in``
-    ``==`` (or ``=``), ``!=``, ``>``, ``>=``, ``<`` and ``<=``.
+    ``==``, ``!=``, ``>``, ``>=``, ``<`` and ``<=``.
 
     Operator precedence follows Python.
     """

django/template/smartif.py

@@ -1,6 +1,9 @@
 """
 Parser and utilities for the smart 'if' tag
 """
+import warnings
+
+from django.utils.deprecation import RemovedInDjango20Warning
 
 
 # Using a simple top down parser, as described here:
@@ -99,6 +102,7 @@ OPERATORS = {
     'not': prefix(8, lambda context, x: not x.eval(context)),
     'in': infix(9, lambda context, x, y: x.eval(context) in y.eval(context)),
     'not in': infix(9, lambda context, x, y: x.eval(context) not in y.eval(context)),
+    # This should be removed in Django 2.0:
     '=': infix(10, lambda context, x, y: x.eval(context) == y.eval(context)),
     '==': infix(10, lambda context, x, y: x.eval(context) == y.eval(context)),
     '!=': infix(10, lambda context, x, y: x.eval(context) != y.eval(context)),
@@ -174,6 +178,11 @@ class IfParser(object):
         except (KeyError, TypeError):
             return self.create_var(token)
         else:
+            if token == '=':
+                warnings.warn(
+                    "Operator '=' is deprecated and will be removed in Django 2.0. Use '==' instead.",
+                    RemovedInDjango20Warning, stacklevel=2
+                )
             return op()
 
     def next_token(self):