Upgraded Django 1.8 to 1.11, getting lots of VariableDoesNotExist errors

The keys it’s trying to look for include:

• in pipeline/js.html:
  • async
  • defer
• in pipeline/css.html:
  • title
  • charset

The keys available are:

• url
• media (only available in pipeline/css.html
• type

[asfaltboy]

The most prominent place where this always appears in pipeline is pipeline/css.html

All 3 variables media, title and charset don’t have default values and raise a KeyError in the renderer. Adding a default value in pipeline’s render context will resolve this, and most probably reduce some noise (which could result in a slight performance boost).

I can submit a PR if adding defaults sounds reasonable, but not sure what I would go with, probably either empty string or None , what do you say @hsiaoyi0504 ?

05-06-2019 06:13:13 DEBUG   MainProcess 64398 django.template [base.py:878] Exception while resolving variable 'media' in template 'pipeline/css.html'.
Traceback (most recent call last):
  File "/Users/pavel.savchenko/.virtualenvs/test/lib/python3.6/site-packages/django/template/base.py", line 835, in _resolve_lookup
    current = current[bit]
  File "/Users/pavel.savchenko/.virtualenvs/test/lib/python3.6/site-packages/django/template/context.py", line 83, in __getitem__
    raise KeyError(key)
KeyError: 'media'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/pavel.savchenko/.virtualenvs/test/lib/python3.6/site-packages/django/template/base.py", line 841, in _resolve_lookup
    if isinstance(current, BaseContext) and getattr(type(current), bit):
AttributeError: type object 'Context' has no attribute 'media'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/pavel.savchenko/.virtualenvs/test/lib/python3.6/site-packages/django/template/base.py", line 849, in _resolve_lookup
    current = current[int(bit)]
ValueError: invalid literal for int() with base 10: 'media'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/pavel.savchenko/.virtualenvs/test/lib/python3.6/site-packages/django/template/base.py", line 856, in _resolve_lookup
    (bit, current))  # missing attribute
django.template.base.VariableDoesNotExist: Failed lookup for key [media] in [{'True': True, 'False': False, 'None': None}, {'type': 'text/css', 'url': '/static/ui/assets/styles/styles.css'}]

[delenamalan]

Solution for us was to create default “extra content” objects and add it to all of our stylesheets and scripts, e.g.:

default_stylesheet_extra_content = {
    'media': 'all',
    'charset': None,
    'title': None,
}

PIPELINE['STYLESHEETS'] = {
    'countdown': {
        'source_filenames': (
            'css/jquery.countdown-v1.6.0.css',
            'sass/countdown.scss',
        ),
        'output_filename': 'css/countdown.css',
        'extra_context': default_stylesheet_extra_content, 
    },
   ...
}

default_js_extra_content = {
    'async': False,
    'defer': False,
}

PIPELINE['JAVASCRIPT'] = {
    'feeds': {
        'source_filenames': (
            'js/feeds.js',
        ),
        'output_filename': 'js/feeds.js',
        'extra_context': default_js_extra_content, 
    },
   ...
}

@asfaltboy’s suggested solution would’ve been great though.