reflex-dev/reflex · error · VarDependencyError

Cannot track dependencies without caching.

Error message

Cannot track dependencies without caching.

What it means

Raised when dependencies (deps=[...] or auto_deps=False) are supplied for a computed var while cache=False. Dependency tracking only applies to cached computed vars, so reflex rejects the combination.

Source

Thrown at packages/reflex-base/src/reflex_base/vars/base.py:2984

        interval: Interval at which the computed var should be updated.
        backend: Whether the computed var is a backend var.
        **kwargs: additional attributes to set on the instance

    Returns:
        A ComputedVar instance.

    Raises:
        ValueError: If caching is disabled and an update interval is set.
        VarDependencyError: If user supplies dependencies without caching.
        ComputedVarSignatureError: If the getter function has more than one argument.
    """
    if cache is False and interval is not None:
        msg = "Cannot set update interval without caching."
        raise ValueError(msg)

    if cache is False and (deps is not None or auto_deps is False):
        msg = "Cannot track dependencies without caching."
        raise VarDependencyError(msg)

    if fget is not None:
        sign = inspect.signature(fget)
        if len(sign.parameters) != 1:
            raise ComputedVarSignatureError(fget.__name__, signature=str(sign))

        if inspect.iscoroutinefunction(fget):
            computed_var_cls = AsyncComputedVar
        else:
            computed_var_cls = ComputedVar
        return computed_var_cls(
            fget,
            initial_value=initial_value,
            cache=cache,
            deps=deps,
            auto_deps=auto_deps,
            interval=interval,
            backend=backend,

View on GitHub (pinned to 45b8ed5ab7)

Solutions

1. Remove deps/auto_deps and let automatic dependency detection run with caching enabled (default), or
2. Keep deps but set cache=True

Example fix

# before
@rx.memo(cache=False, deps=[State.count])
def doubled(self) -> int: return self.count * 2
# after
@rx.memo(deps=[State.count])
def doubled(self) -> int: return self.count * 2

if cache is False and (deps is not None or auto_deps is False):
    raise ValueError('deps/auto_deps require cache=True')

When it happens

Trigger: @rx.memo(cache=False, deps=[State.foo]) or passing auto_deps=False with cache=False to rx.computed.

Common situations: Migrating from manual deps to automatic dependency tracking and leaving cache=False behind; mixing legacy arg patterns in one decorator.

Related errors

• ComputedVar dependencies must be Var instances or var names
• ComputedVar dependencies must be Var instances with a state
• Cannot set update interval without caching.
• Do not override _add_style directly. Use add_style instead.
• UntypedComputedVarError(var_name=fget.__name__)

AI-assisted analysis of reflex-dev/reflex@45b8ed5ab7 (2026-08-28). Data as JSON: /api/errors/c89cc99ae127ba6e. Report an issue: GitHub.