Cache workspace layouts instead of running a script on every switch (#15028)

* Cache workspace layouts instead of running a script on every switch

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Test the workspace layout cache by running its logic, not matching its source

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Keep the fake layout read running while its exit handler runs

Addresses Codex review: clearing running first let an undeferred, broken retry pass the cache tests.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

test/shell.d/hyprland-floating-workspaces-test.sh

@@ -455,3 +455,72 @@ assert(bar and bar.bar_color == "rgb(223344)", "titlebars missed the theme with
   fail "titlebars follow the theme when XDG_STATE_HOME points elsewhere"
 fi
 pass "titlebars follow the theme when XDG_STATE_HOME points elsewhere"
+
+run_node_test <<'JS'
+const source = require('fs').readFileSync(path.join(root, 'shell/plugins/bar/widgets/Workspaces.qml'), 'utf8')
+assert(source.includes('function onFocusedWorkspaceChanged() { root.showFocusedMode() }'), 'a workspace switch shows the cached layout instead of running the script')
+assert(source.includes('String(event.name) === "configreloaded") root.refresh()'), 'a config reload drops every cached layout')
+
+// Run the widget's own cache logic against a fake Hyprland and process.
+function body(pattern) {
+  const match = source.match(pattern)
+  if (!match) fail('Workspaces.qml cache logic can be extracted', String(pattern))
+  return match[1]
+}
+// QML resolves bare calls like readMode() on the widget, so it is passed in too.
+const args = ['root', 'Hyprland', 'modeProc', 'Qt', 'readMode']
+const fn = name => new Function(...args, body(new RegExp(`\\n  function ${name}\\(\\) \\{([\\s\\S]*?)\\n  \\}`)))
+const streamFinished = new Function(...args, 'text', body(/onStreamFinished: \{([\s\S]*?)\n      \}/))
+const exited = new Function(...args, body(/onExited: \{([\s\S]*?)\n    \}/))
+
+const hyprland = { focusedWorkspace: { id: 1 } }
+const proc = { running: false, command: null, runs: [] }
+const deferred = []
+const qt = { callLater: callback => deferred.push(callback) }
+const widget = { focusedMode: 'dwindle', modeStale: false, modeCache: {}, modeGeneration: 0, modeProcWorkspace: -1, modeProcGeneration: 0 }
+for (const name of ['focusedWorkspaceId', 'showFocusedMode', 'readMode', 'refresh']) {
+  const call = fn(name)
+  widget[name] = () => call(widget, hyprland, proc, qt, widget.readMode)
+}
+const start = () => { if (proc.running) proc.runs.push(proc.command[1]) }
+// Quickshell still reports the process running while it signals exit, so a
+// retry has to be deferred until after the handler returns.
+const finish = output => {
+  streamFinished(widget, hyprland, proc, qt, widget.readMode, output)
+  exited(widget, hyprland, proc, qt, widget.readMode)
+  proc.running = false
+  while (deferred.length) deferred.shift()()
+}
+const focus = id => { hyprland.focusedWorkspace = { id }; widget.showFocusedMode(); start() }
+
+widget.refresh(); start()
+finish('scrolling\n')
+assertEqual(widget.focusedMode, 'scrolling', 'the first read shows the focused layout')
+focus(2); finish('floating\n')
+focus(1)
+assertEqual(widget.focusedMode, 'scrolling', 'returning to a read workspace shows its cached layout')
+assertDeepEqual(proc.runs, ['1', '2'], 'a cached workspace switch runs no script')
+
+widget.refresh(); start()
+assert(proc.running && proc.runs.length === 3, 'a refresh reads the focused layout again')
+assertDeepEqual(widget.modeCache, {}, 'a refresh drops every cached layout')
+widget.refresh()
+assert(widget.modeStale, 'a refresh during a read marks it stale')
+finish('dwindle\n')
+assert(widget.modeCache[1] === undefined, 'a read that predates a refresh is not cached')
+start()
+assertDeepEqual(proc.runs, ['1', '2', '1', '1'], 'a stale read is retried once it exits')
+finish('floating\n')
+assertEqual(widget.focusedMode, 'floating', 'the retried read shows the current layout')
+
+widget.refresh(); start()
+focus(2)
+assert(widget.modeStale, 'switching to an uncached workspace during a read marks it pending')
+finish('scrolling\n')
+assertEqual(widget.modeCache[1], 'scrolling', 'the in-flight read still caches its own workspace')
+assertEqual(widget.focusedMode, 'floating', 'a read for a workspace no longer focused leaves the shown layout alone')
+start()
+assertEqual(proc.runs[proc.runs.length - 1], '2', 'the pending read follows the newly focused workspace')
+finish('dwindle\n')
+assertEqual(widget.focusedMode, 'dwindle', 'the newly focused workspace shows its own layout')
+JS