zed-industries/zed · error

should only be called once

Error message

should only be called once

What it means

Animation element's request_layout expects a one-time take of animation start state (the 'should only be called once' expect): the element's request_layout ran twice without a fresh element state, e.g. the element instance was reused across frames or request_layout is called outside the normal layout/prepaint sequence.

Source

Thrown at crates/gpui/src/elements/animation.rs:344

                SpringPlayback::Completed => {
                    state.spring = SpringState {
                        position: state.target,
                        velocity: 0.0,
                    };
                    true
                }
                SpringPlayback::Cancelled => {
                    state.spring = SpringState {
                        position: state.initial,
                        velocity: 0.0,
                    };
                    true
                }
            };
            state.playback = self.playback;
            state.updated_at = now;

            let element = self.element.take().expect("should only be called once");
            let animator = self.animator.take().expect("should only be called once");
            let mut element = animator(element, state.spring.position).into_any_element();

            if !done {
                window.request_animation_frame();
            }

            ((element.request_layout(window, cx), element), state)
        })
    }

    fn prepaint(
        &mut self,
        _id: Option<&GlobalElementId>,
        _inspector_id: Option<&InspectorElementId>,
        _bounds: crate::Bounds<crate::Pixels>,
        element: &mut Self::RequestLayoutState,
        window: &mut Window,

View on GitHub (pinned to f4178619ac)

Solutions

1. Ensure the animation element is used once per frame within the standard element lifecycle
2. Don't call request_layout manually or reuse the element struct across renders
3. Check that element state initialization happens exactly once before animation starts

When it happens

Trigger: Thrown at crates/gpui/src/elements/animation.rs:344 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of zed-industries/zed@f4178619ac (2026-08-20). Data as JSON: /api/errors/e6825eeb8c45cfc1. Report an issue: GitHub.