Commit fef0d25b authored by Russell Keith-Magee's avatar Russell Keith-Magee
Browse files

Fixed #13373 -- Ensured that {% if %} statements will short circuit template... 

Fixed #13373 -- Ensured that {% if %} statements will short circuit template logic and not evaluate clauses that don't require evaluation. Thanks to Jerry Stratton for the report.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@13001 bcc190cf-cafb-0310-a4f2-bffc1f526a37
parent ebfe9383

django/template/smartif.py

+17 −16
Original line number Diff line number Diff line
@@ -56,7 +56,7 @@ def infix(bp, func): 


        def eval(self, context):

            try:

                return func(self.first.eval(context), self.second.eval(context))

                return func(context, self.first, self.second)

            except Exception:

                # Templates shouldn't throw exceptions when rendering.  We are

                # most likely to get exceptions for things like {% if foo in bar
@@ -81,7 +81,7 @@ def prefix(bp, func): 


        def eval(self, context):

            try:

                return func(self.first.eval(context))

                return func(context, self.first)

            except Exception:

                return False
@@ -91,20 +91,21 @@ def prefix(bp, func): 
# Operator precedence follows Python.

# NB - we can get slightly more accurate syntax error messages by not using the

# same object for '==' and '='.



# We defer variable evaluation to the lambda to ensure that terms are

# lazily evaluated using Python's boolean parsing logic.

OPERATORS = {

    'or': infix(6, lambda x, y: x or y),

    'and': infix(7, lambda x, y: x and y),

    'not': prefix(8, operator.not_),

    'in': infix(9, lambda x, y: x in y),

    'not in': infix(9, lambda x, y: x not in y),

    '=': infix(10, operator.eq),

    '==': infix(10, operator.eq),

    '!=': infix(10, operator.ne),

    '>': infix(10, operator.gt),

    '>=': infix(10, operator.ge),

    '<': infix(10, operator.lt),

    '<=': infix(10, operator.le),

    'or': infix(6, lambda context, x, y: x.eval(context) or y.eval(context)),

    'and': infix(7, lambda context, x, y: x.eval(context) and y.eval(context)),

    '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)),

    '=': 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)),

    '>': 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)),

    '<=': infix(10, lambda context, x, y: x.eval(context) <= y.eval(context)),

}



# Assign 'id' to each:

tests/regressiontests/templates/tests.py

+30 −1
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ if __name__ == '__main__': 
    settings.configure()



from datetime import datetime, timedelta

import time

import os

import sys

import traceback
@@ -97,6 +98,17 @@ class OtherClass: 
    def method(self):

        return "OtherClass.method"



class TestObj(object):

    def is_true(self):

        return True



    def is_false(self):

        return False



    def is_bad(self):

        time.sleep(0.3)

        return True



class SilentGetItemClass(object):

    def __getitem__(self, key):

        raise SomeException
@@ -342,6 +354,11 @@ class Templates(unittest.TestCase): 
        old_invalid = settings.TEMPLATE_STRING_IF_INVALID

        expected_invalid_str = 'INVALID'



        # Warm the URL reversing cache. This ensures we don't pay the cost

        # warming the cache during one of the tests.

        urlresolvers.reverse('regressiontests.templates.views.client_action',

                             kwargs={'id':0,'action':"update"})



        for name, vals in tests:

            if isinstance(vals[2], tuple):

                normal_string_result = vals[2][0]
@@ -367,9 +384,14 @@ class Templates(unittest.TestCase): 
                        start = datetime.now()

                        test_template = loader.get_template(name)

                        end = datetime.now()

                        output = self.render(test_template, vals)

                        if end-start > timedelta(seconds=0.2):

                            failures.append("Template test (Cached='%s', TEMPLATE_STRING_IF_INVALID='%s'): %s -- FAILED. Took too long to parse test" % (is_cached, invalid_str, name))



                        start = datetime.now()

                        output = self.render(test_template, vals)

                        end = datetime.now()

                        if end-start > timedelta(seconds=0.2):

                            failures.append("Template test (Cached='%s', TEMPLATE_STRING_IF_INVALID='%s'): %s -- FAILED. Took too long to render test" % (is_cached, invalid_str, name))

                    except ContextStackException:

                        failures.append("Template test (Cached='%s', TEMPLATE_STRING_IF_INVALID='%s'): %s -- FAILED. Context stack was left imbalanced" % (is_cached, invalid_str, name))

                        continue
@@ -782,6 +804,13 @@ class Templates(unittest.TestCase): 
            'if-tag-error11': ("{% if 1 == %}yes{% endif %}", {}, template.TemplateSyntaxError),

            'if-tag-error12': ("{% if a not b %}yes{% endif %}", {}, template.TemplateSyntaxError),



            # If evaluations are shortcircuited where possible

            # These tests will fail by taking too long to run. When the if clause

            # is shortcircuiting correctly, the is_bad() function shouldn't be

            # evaluated, and the deliberate sleep won't happen.

            'if-tag-shortcircuit01': ('{% if x.is_true or x.is_bad %}yes{% else %}no{% endif %}', {'x': TestObj()}, "yes"),

            'if-tag-shortcircuit02': ('{% if x.is_false and x.is_bad %}yes{% else %}no{% endif %}', {'x': TestObj()}, "no"),



            # Non-existent args

            'if-tag-badarg01':("{% if x|default_if_none:y %}yes{% endif %}", {}, ''),

            'if-tag-badarg02':("{% if x|default_if_none:y %}yes{% endif %}", {'y': 0}, ''),