Forloop with a filter that has an argument containing whitespace raises a TemplateSyntaxError

[Baptiste Mispelon]

In a template, when looping over a variable that has a filter with an argument containing whitespace, a TemplateSyntaxError will be thrown.

Here's a small test case to reproduce the issue (the first template fails while the other two work as expected):

from django.template import Template, Context

for tpl in [
        '{% for x in ""|add:"a b c" %}{{ x }}{% endfor %}', # Doesn't work
        '{% with v=""|add:"a b c" %}{% for x in v %}{{ x }}{% endfor %}{% endwith %}',
        '{% with v="a b c" %}{% for x in ""|add:v %}{{ x }}{% endfor %}{% endwith %}'
    ]:
    s = Template(tpl).render(Context())
    assert s == u'a b c'

Here's the traceback that this produces:

Traceback (most recent call last):
  File "my_script.py", line 8, in <module>
    s = Template(tpl).render(Context())
  File "/path/to/venv/local/lib/python2.7/site-packages/django/template/base.py", line 125, in __init__
    self.nodelist = compile_string(template_string, origin)
  File "/path/to/venv/local/lib/python2.7/site-packages/django/template/base.py", line 153, in compile_string
    return parser.parse()
  File "/path/to/venv/local/lib/python2.7/site-packages/django/template/base.py", line 278, in parse
    compiled_result = compile_func(self, token)
  File "/path/to/venv/local/lib/python2.7/site-packages/django/template/defaulttags.py", line 758, in do_for
    " 'for x in y': %s" % token.contents)
django.template.base.TemplateSyntaxError: 'for' statements should use the format 'for x in y': for x in ""|add:"a b c"

It looks like token.contents.split() in the code of the tag gets confused by the whitespace and splits the string into too many parts.

Since the code searches for the "in" keyword from the end (position -2 since we are not reversed), then it fails.

[Carl Meyer]

Reproduced; this is clearly a bug. Thanks for the report!

[Baptiste Mispelon <bmispelon@…>]

In f13bfbec70e096f230e3dcda88a2cb215e7f8899:

Fixed #19882 -- Smarter tokenizing of {% for %} tag arguments.