nodejs/node · error · TemplateRuntimeError

Attempted to invoke context filter without context

Error message

Attempted to invoke context filter without context

What it means

Raised by Environment.call_filter (jinja2 environment.py) when the resolved filter function is decorated with @contextfilter (it needs the render Context) but call_filter was invoked without a context argument. Context filters can only run inside the template engine, which always passes the active context; calling them through the public call_filter API without one is unsupported.

Source

Thrown at tools/inspector_protocol/jinja2/environment.py:455

    def call_filter(self, name, value, args=None, kwargs=None,
                    context=None, eval_ctx=None):
        """Invokes a filter on a value the same way the compiler does it.

        Note that on Python 3 this might return a coroutine in case the
        filter is running from an environment in async mode and the filter
        supports async execution.  It's your responsibility to await this
        if needed.

        .. versionadded:: 2.7
        """
        func = self.filters.get(name)
        if func is None:
            fail_for_missing_callable('no filter named %r', name)
        args = [value] + list(args or ())
        if getattr(func, 'contextfilter', False):
            if context is None:
                raise TemplateRuntimeError('Attempted to invoke context '
                                           'filter without context')
            args.insert(0, context)
        elif getattr(func, 'evalcontextfilter', False):
            if eval_ctx is None:
                if context is not None:
                    eval_ctx = context.eval_ctx
                else:
                    eval_ctx = EvalContext(self)
            args.insert(0, eval_ctx)
        elif getattr(func, 'environmentfilter', False):
            args.insert(0, self)
        return func(*args, **(kwargs or {}))

    def call_test(self, name, value, args=None, kwargs=None):
        """Invokes a test on a value the same way the compiler does it.

        .. versionadded:: 2.7
        """

View on GitHub (pinned to 1b2de5e052)

Solutions

1. Pass a context: `env.call_filter('my_ctx_filter', value, context=ctx)` where ctx is a real Context obtained from template.new_context().
2. If you do not have a context, use a non-contextfilter version of the filter (drop @contextfilter or wrap it).
3. Run such filters from inside a template expression where the engine injects context automatically.

Example fix

# before
env.call_filter('my_ctx_filter', value)
# after
ctx = template.new_context({'value': value})
env.call_filter('my_ctx_filter', value, context=ctx)

def needs_context(env, name) -> bool:
    return getattr(env.filters.get(name), 'contextfilter', False)

# before calling:
if needs_context(env, 'my_ctx_filter') and context is None:
    context = template.new_context(vars)

When it happens

Trigger: Calling `env.call_filter('my_ctx_filter', value)` where my_ctx_filter is a @contextfilter, and omitting the context= kwarg; reusing a context filter as a plain Python function from outside a template.

Common situations: Sharing a custom filter between template use (needs context) and ad-hoc script use (no context); calling a third-party @contextfilter from application code rather than from inside a template.

Related errors

• %s (%s; did you forget to quote the callable name?)
• either extensions or filter_func can be passed, but not both
• You can only sort by either "key" or "value"
• can't handle positional and keyword arguments at the same ti
• method must be common, ceil or floor

AI-assisted analysis of nodejs/node@1b2de5e052 (2026-08-13). Data as JSON: /api/errors/86ba0609bfbe4cc2. Report an issue: GitHub.