---
theme: url-state
heading: "URL state — routing, query strings and selection"
kind: theme
---

**Grouped 2026-08-21.** This was `files-app`, and the file browser is still where most of it is —
but the question underneath is not the file browser's. Where selection lives, what a query string is
allowed to mean, and who is responsible for clearing one are framework questions that happen to have
been answered first in `/files`. The panel framework's own version of the same question is here too,
rather than filed under the framework's deep read where nobody comparing the two would find it.

`docs/navigation-audit.md` is the authority for all of it.

**The URL model is done (2026-08-15).** The folder is the pathname —
`/files/archive/Tests/platform/docs` — and `?view=` is a NAME within it, not a second copy of the path.
Deep links and refresh work, which they never had. Landed across `559560de`, `98ba604a`, `7e31564c`,
`0dc88b51`, `7359af2f`, with `files-route.ts` + 23 tests as the one owner of encoding and of which params
belong to the overlay.

Four bugs came out of that work and are fixed: closing a pane sent you home; `?view=` was stripped on
every page load by a mount effect that had made deep links impossible since 2026-02-23; navigating kept a
pane belonging to the folder you left; and the breadcrumb opted out of that last rule because it is a
`<Link>` and never called the function enforcing it.

**A fifth, fixed 2026-08-21.** The URL survived a refresh and the pane still did not open — reported as
"refresh loses the panel, and then the file won't open". Nothing to do with the query string this time:
`WorkspaceView` gave the ephemeral pane `defaultSize={0}` and opened it from an effect calling
`panel.resize()`, so open/closed lived in two places. On a deep link the effect ran before
`workspace.isLoaded` was true — when the early return means nothing is rendered and the ref is null — and
its deps could not change afterwards, so it never ran again. The second half is what made it look like a
click bug: with `?view=` already naming the file, double-clicking it changed no state, so nothing re-ran.
The pane is now rendered conditionally with `id` + `order` and sized declaratively; `ephemeral-pane.test.tsx`
asserts the SIZE rather than the element's presence, because a pane at zero width passes any
"is it in the document" check. Five of its six tests fail against the old implementation.

The shape is worth keeping in mind for the rest of this theme: **state that the URL owns, mirrored into an
imperative correction, will eventually be read at a moment the correction cannot run.**