zed-industries/zed · error

Missing document

Error message

Missing document

What it means

A sentinel guard in WebViewport::update: window.document() returned None while recomputing canvas bounds and safe-area insets for the frame. Per web-sys this only happens for non-HTML or transitional documents, so during a normal session it indicates the window/document is being torn down or is in an invalid state mid-update. The update aborts and the old cached bounds are kept.

Source

Thrown at crates/gpui_web/src/viewport.rs:51

    }

    pub(crate) fn observe_safe_area(&self, observer: &web_sys::ResizeObserver) {
        // Separate boxes detect redistribution between edges even when the
        // total inset, and therefore a single combined probe's size, is unchanged.
        for probe in &self.safe_area_probes {
            observer.observe(probe);
        }
    }

    pub(crate) fn update(
        &mut self,
        window: &web_sys::Window,
        canvas: &web_sys::HtmlCanvasElement,
    ) -> anyhow::Result<bool> {
        let canvas_bounds = canvas.get_bounding_client_rect();
        let document = window
            .document()
            .ok_or_else(|| anyhow::anyhow!("Missing document"))?;
        let root = document
            .document_element()
            .ok_or_else(|| anyhow::anyhow!("Missing root"))?;
        let layout_width = root.client_width() as f64;
        let layout_height = root.client_height() as f64;
        let (left, top, width, height) = match window.visual_viewport() {
            Some(viewport) => (
                viewport.offset_left(),
                viewport.offset_top(),
                viewport.width(),
                viewport.height(),
            ),
            None => (0., 0., layout_width, layout_height),
        };
        // VisualViewport offsets and getBoundingClientRect share layout CSS
        // coordinates. Multiplying by the pinch scale here would incorrectly
        // expand the visible rectangle back to its unzoomed size.
        let x = (left - canvas_bounds.left()).clamp(0., canvas_bounds.width());

View on GitHub (pinned to 9d272b0363)

Solutions

1. Treat as a transient teardown signal: skip this frame's viewport update and keep the previous bounds
2. Ensure update() is not invoked after the window is closed or during document unload
3. If persistent, inspect the hosting document type; webviews serving XHTML or non-HTML content can trigger this

When it happens

Trigger: Thrown at crates/gpui_web/src/viewport.rs:51 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of zed-industries/zed@9d272b0363 (2026-09-12). Data as JSON: /api/errors/371c8db762975e48. Report an issue: GitHub.