DioxusLabs/dioxus · error

parent mount

Error message

parent mount

What it means

Internal invariant: resolving a slot required reading a parent mount's current vnode, but the mount table had no view for that MountId. The mount was removed or never committed — a framework consistency bug.

Source

Thrown at packages/core/src/diff/placement.rs:334

        &self,
        parent_mount: MountId,
        version: ParentVersion,
        f: impl FnOnce(&VNode) -> Option<T>,
    ) -> Option<T> {
        if let Some(frame) = self
            .context
            .and_then(|context| context.for_mount(parent_mount))
        {
            let vnode = match version {
                ParentVersion::Old => frame.old,
                ParentVersion::New => frame.new,
            };
            f(vnode)
        } else {
            let vnode = self
                .dom
                .current_mounted_view(parent_mount)
                .expect("parent mount");
            f(&vnode)
        }
    }

    fn vnode_first_site(&self, vnode: MountedVNode<'_>) -> Option<InsertionSite> {
        vnode
            .find_first_element(self.dom)
            .map(InsertionSite::before)
    }

    fn anchor_site(&self, anchor: DynamicAnchor<'_>, anchor_id: ElementId) -> InsertionSite {
        if anchor.is_parent_append_target() {
            InsertionSite::append_to(anchor_id)
        } else if anchor.is_last_static_node() {
            InsertionSite::after(anchor_id)
        } else {
            InsertionSite::before(anchor_id)
        }

View on GitHub (pinned to 24f6a829df)

Solutions

1. This is an internal invariant about parent mounts. Report it with a minimal reproduction to the Dioxus issue tracker.

When it happens

Trigger: Thrown at packages/core/src/diff/placement.rs:334 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of DioxusLabs/dioxus@24f6a829df (2026-08-23). Data as JSON: /api/errors/691bd667ea87a46d. Report an issue: GitHub.