omacom · kristofferR · Sep 9, 2026
diff --git a/shell/plugins/bar/Bar.qml b/shell/plugins/bar/Bar.qml
@@ -3,6 +3,7 @@ import Quickshell.Hyprland
 import Quickshell.Io
 import Quickshell.Wayland
 import QtQuick
+import QtQml.Models
 import QtQuick.Layouts
 import qs.Commons
 import qs.Ui
@@ -63,7 +64,6 @@ Item {
   readonly property bool barHovered: barHoverCount > 0
   property bool centerSectionRevealHeld: false
   property bool centerHoverRevealSuppressed: false
-  property int barConfigSerial: 0
   property string position: "top"
   // Resolves through fontconfig at paint time (Style.font.family defaults
   // to "monospace"), so changing the system font (via `omarchy-font-set`)
@@ -585,38 +585,13 @@ Item {
     setRequestedTransparency(config.transparent === true)
     centerAnchor = Util.canonicalWidgetId(config.centerAnchor || "")
 
-    // layoutEntries feeds plain JS arrays to the module Repeaters, and QML
-    // cannot diff those: reassigning layoutConfig rebuilds every widget on
-    // every monitor. When a shell.json write only changed inline widget
-    // settings, patch the live layout and running widgets in place instead.
     var next = normalizeLayout(config.layout)
-    var delta = BarModel.inlineSettingsDelta(layoutConfig, next)
-    if (delta) {
-      applySettingsDelta(delta)
-      return
-    }
-    layoutConfig = next
-    barConfigSerial++
-  }
-
-  function applySettingsDelta(delta) {
-    for (var i = 0; i < delta.length; i++) {
-      var change = delta[i]
-      layoutConfig[change.region][change.index] = change.entry
-      var settings = entrySettings(change.entry)
-      for (var s = 0; s < moduleSlots.length; s++) {
-        var slot = moduleSlots[s]
-        if (!slot || slot.region !== change.region || slot.moduleName !== entryId(change.entry)) continue
-        var item = slot.activeItem
-        if (item && "settings" in item) item.settings = settings
-      }
-    }
+    if (JSON.stringify(layoutConfig) !== JSON.stringify(next)) layoutConfig = next
   }
 
   onBarConfigChanged: applyBarConfig()
 
   function layoutEntries(region) {
-    var serial = barConfigSerial
     var entries = layoutConfig ? layoutConfig[region] : null
     return Array.isArray(entries) ? entries : []
   }
@@ -1722,6 +1697,10 @@ Item {
     property var entries: []
     property string region: ""
 
+    ListModel { id: entryModel }
+    onEntriesChanged: BarModel.syncEntries(entryModel, entries)
+    Component.onCompleted: BarModel.syncEntries(entryModel, entries)
+
     visible: entries.length > 0
     // A hidden list must not build its modules. The center section declares
     // both an anchored and an unanchored arrangement and shows whichever
@@ -1740,11 +1719,11 @@ Item {
         spacing: 0
 
         Repeater {
-          model: moduleListRoot.entries
+          model: entryModel
 
           ModuleSlot {
-            required property var modelData
-            entry: modelData
+            required property string entryJson
+            entry: JSON.parse(entryJson)
             region: moduleListRoot.region
           }
         }
@@ -1758,11 +1737,11 @@ Item {
         spacing: 0
 
         Repeater {
-          model: moduleListRoot.entries
+          model: entryModel
 
           ModuleSlot {
-            required property var modelData
-            entry: modelData
+            required property string entryJson
+            entry: JSON.parse(entryJson)
             region: moduleListRoot.region
           }
         }

diff --git a/shell/plugins/bar/BarModel.js b/shell/plugins/bar/BarModel.js
@@ -1,3 +1,58 @@
+// Keep delegates alive across layout edits. Reserve exact matches first so
+// changing one of several instances does not steal an unchanged instance.
+// JSON stays a string role: ListModel otherwise turns nested settings arrays
+// into nested models, changing the widget settings contract.
+function syncEntries(model, entries) {
+  var rows = []
+  var used = []
+  var nextKey = 0
+  for (var i = 0; i < model.count; i++) {
+    var row = model.get(i)
+    rows.push({ key: row.instanceKey, json: row.entryJson, id: entryId(JSON.parse(row.entryJson)) })
+    nextKey = Math.max(nextKey, row.instanceKey + 1)
+  }
+  var wanted = entries.map(function(entry) {
+    return { id: entryId(entry), json: JSON.stringify(entry), match: -1 }
+  })
+  for (var exact = 0; exact < wanted.length; exact++) {
+    for (var old = 0; old < rows.length; old++) {
+      if (!used[old] && rows[old].json === wanted[exact].json) {
+        wanted[exact].match = old
+        used[old] = true
+        break
+      }
+    }
+  }
+  for (var n = 0; n < wanted.length; n++) {
+    var item = wanted[n]
+    if (item.match < 0) {
+      for (var candidate = 0; candidate < rows.length; candidate++) {
+        if (!used[candidate] && rows[candidate].id === item.id) {
+          item.match = candidate
+          used[candidate] = true
+          break
+        }
+      }
+    }
+    item.key = item.match < 0 ? nextKey++ : rows[item.match].key
+  }
+  for (var remove = rows.length - 1; remove >= 0; remove--) {
+    if (!used[remove]) model.remove(remove)
+  }
+  for (var target = 0; target < wanted.length; target++) {
+    var entry = wanted[target]
+    var source = target
+    while (source < model.count && model.get(source).instanceKey !== entry.key) source++
+    if (source === model.count) {
+      model.insert(target, { instanceKey: entry.key, entryJson: entry.json })
+    } else {
+      if (source !== target) model.move(source, target, 1)
+      if (model.get(target).entryJson !== entry.json)
+        model.setProperty(target, "entryJson", entry.json)
+    }
+  }
+}
+
 function isPlainObject(value) {
   return !!value && typeof value === "object" && !Array.isArray(value)
 }
@@ -65,42 +120,6 @@ function entriesAfter(entries, name) {
   return index === -1 ? [] : entries.slice(index + 1)
 }
 
-// A shell.json write that only changes inline widget settings (the battery
-// percentage toggle, a clock format change) must not rebuild the bar.
-// Compare two normalized layouts: when the structure is unchanged — same
-// entry ids in the same order per region — return the settings-only changes
-// as {region, index, entry}. Return null when the change is structural, or
-// touches an entry a live settings push cannot safely reach: custom modules
-// read their entry directly rather than an injected settings property, and
-// a duplicated id makes the push ambiguous.
-function inlineSettingsDelta(current, next) {
-  if (!isPlainObject(current) || !isPlainObject(next)) return null
-  var regions = ["left", "center", "right"]
-  var counts = {}
-  for (var r = 0; r < regions.length; r++) {
-    var entries = Array.isArray(next[regions[r]]) ? next[regions[r]] : []
-    for (var i = 0; i < entries.length; i++) {
-      var id = entryId(entries[i])
-      counts[id] = (counts[id] || 0) + 1
-    }
-  }
-  var changes = []
-  for (var s = 0; s < regions.length; s++) {
-    var region = regions[s]
-    var a = Array.isArray(current[region]) ? current[region] : []
-    var b = Array.isArray(next[region]) ? next[region] : []
-    if (a.length !== b.length) return null
-    for (var j = 0; j < a.length; j++) {
-      if (entryId(a[j]) !== entryId(b[j])) return null
-      if (JSON.stringify(a[j]) === JSON.stringify(b[j])) continue
-      if (customModuleType(a[j]) || customModuleType(b[j])) return null
-      if (counts[entryId(b[j])] > 1) return null
-      changes.push({ region: region, index: j, entry: b[j] })
-    }
-  }
-  return changes
-}
-
 function expandPath(value, home) {
   var path = String(value || "")
   if (path === "") return ""
@@ -210,6 +229,7 @@ function nearestDropTarget(candidates, point, vertical) {
 
 if (typeof module !== "undefined") {
   module.exports = {
+    syncEntries: syncEntries,
     isDrawnSlot: isDrawnSlot,
     pickDrawnSlot: pickDrawnSlot,
     pickPanelSlot: pickPanelSlot,
@@ -222,7 +242,6 @@ if (typeof module !== "undefined") {
     entryIndex: entryIndex,
     entriesBefore: entriesBefore,
     entriesAfter: entriesAfter,
-    inlineSettingsDelta: inlineSettingsDelta,
     expandPath: expandPath,
     customModuleSafeName: customModuleSafeName,
     customModuleType: customModuleType,

diff --git a/test/shell.d/bar-layout-model-test.sh b/test/shell.d/bar-layout-model-test.sh
@@ -0,0 +1,17 @@
+#!/bin/bash
+set -euo pipefail
+source "$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)/base-test.sh"
+if ! command -v quickshell >/dev/null 2>&1; then
+  pass "quickshell not installed; skipping layout model runtime test"
+  exit 0
+fi
+fixture=$(mktemp -d)
+trap 'rm -rf -- "$fixture"' EXIT
+cp -- "$SHELL_TEST_DIR/fixtures/bar-layout-model/shell.qml" "$fixture/shell.qml"
+ln -s -- "$ROOT/shell/plugins/bar/BarModel.js" "$fixture/BarModel.js"
+QT_QPA_PLATFORM=offscreen timeout 10 quickshell -p "$fixture" --no-color >"$fixture/log" 2>&1 || true
+if ! rg -q BAR_LAYOUT_MODEL_OK "$fixture/log" || rg -q 'BAR_LAYOUT_MODEL_FAIL|TypeError|ReferenceError' "$fixture/log"; then
+  cat "$fixture/log" >&2
+  fail "layout changes preserve QML delegates and nested settings"
+fi
+pass "layout changes preserve QML delegates and nested settings"
diff --git a/test/shell.d/bar-test.sh b/test/shell.d/bar-test.sh
@@ -294,50 +294,6 @@ const entries = [{ id: 'a' }, { id: 'omarchy.tray' }, { id: 'b' }]
 assertDeepEqual(bar.pinTrayToInner(entries, 'left').map(bar.entryId), ['a', 'b', 'omarchy.tray'], 'bar pins tray to left inner edge')
 assertDeepEqual(bar.pinTrayToInner(entries, 'right').map(bar.entryId), ['omarchy.tray', 'a', 'b'], 'bar pins tray to right inner edge')
 
-// A settings-only shell.json write must patch the live bar, not rebuild it:
-// the module Repeaters recreate every widget when their array model changes.
-const settingsLayout = { left: [{ id: 'omarchy.power' }], center: [{ id: 'omarchy.clock', format: 'HH:mm' }], right: [] }
-assertDeepEqual(
-  bar.inlineSettingsDelta(settingsLayout, { left: [{ id: 'omarchy.power', showPercentage: true }], center: [{ id: 'omarchy.clock', format: 'HH:mm' }], right: [] }),
-  [{ region: 'left', index: 0, entry: { id: 'omarchy.power', showPercentage: true } }],
-  'bar reports a settings-only change as an inline delta'
-)
-assertDeepEqual(
-  bar.inlineSettingsDelta(settingsLayout, JSON.parse(JSON.stringify(settingsLayout))),
-  [],
-  'bar reports an unchanged layout as an empty delta'
-)
-assertEqual(
-  bar.inlineSettingsDelta(settingsLayout, { left: [{ id: 'omarchy.clock', format: 'HH:mm' }], center: [{ id: 'omarchy.power' }], right: [] }),
-  null,
-  'bar treats reordered entries as structural'
-)
-assertEqual(
-  bar.inlineSettingsDelta(settingsLayout, { left: [{ id: 'omarchy.power' }, { id: 'omarchy.battery' }], center: settingsLayout.center, right: [] }),
-  null,
-  'bar treats added entries as structural'
-)
-assertEqual(
-  bar.inlineSettingsDelta(
-    { left: [{ id: 'local.status', exec: 'date' }], center: [], right: [] },
-    { left: [{ id: 'local.status', exec: 'uptime' }], center: [], right: [] }
-  ),
-  null,
-  'bar rebuilds for custom modules, which read their entry directly'
-)
-assertEqual(
-  bar.inlineSettingsDelta(
-    { left: [{ id: 'x' }], center: [], right: [{ id: 'x' }] },
-    { left: [{ id: 'x', a: 1 }], center: [], right: [{ id: 'x' }] }
-  ),
-  null,
-  'bar rebuilds when a changed id appears more than once in the layout'
-)
-assert(
-  /BarModel\.inlineSettingsDelta\(layoutConfig, next\)/.test(barSource),
-  'bar consults the inline settings delta before rebuilding the layout'
-)
-
 assertEqual(bar.moduleString({ id: 'custom', label: 42 }, 'label', 'fallback'), '42', 'bar stringifies module settings')
 assertEqual(bar.entryIndex(entries, 'b'), 2, 'bar finds entry indexes')
 assertDeepEqual(bar.entriesBefore(entries, 'b').map(bar.entryId), ['a', 'omarchy.tray'], 'bar returns entries before target')

diff --git a/test/shell.d/fixtures/bar-layout-model/shell.qml b/test/shell.d/fixtures/bar-layout-model/shell.qml
@@ -0,0 +1,67 @@
+import QtQuick
+import QtQml.Models
+import Quickshell
+import "BarModel.js" as BarModel
+
+ShellRoot {
+  id: root
+  property int created: 0
+  ListModel { id: entries }
+  Item {
+    Repeater {
+      id: widgets
+      model: entries
+      Item {
+        required property string entryJson
+        property var settings: JSON.parse(entryJson)
+        Component.onCompleted: root.created++
+      }
+    }
+  }
+  function check(value, message) {
+    if (!value) throw new Error(message)
+  }
+  Timer {
+    interval: 1
+    running: true
+    onTriggered: {
+      try {
+        var clock = {id: "clock", format: "HH:mm"}
+        var sound = {id: "groups", groupId: "sound", items: ["audio"]}
+        var devices = {id: "groups", groupId: "devices", items: ["bluetooth"]}
+        BarModel.syncEntries(entries, [clock, sound, devices, "divider", "divider"])
+        var clockItem = widgets.itemAt(0)
+        var soundItem = widgets.itemAt(1)
+        var devicesItem = widgets.itemAt(2)
+        var dividerA = widgets.itemAt(3)
+        var dividerB = widgets.itemAt(4)
+        var initialCreated = root.created
+        BarModel.syncEntries(entries, [clock, sound, devices, "divider", "divider"])
+        check(root.created === initialCreated, "identical config recreated delegates")
+        var movedSound = {id: "groups", groupId: "sound", items: ["audio", {id: "network", nested: {values: [1, 2]}}]}
+        BarModel.syncEntries(entries, [devices, clock, movedSound, "divider", "divider", "network"])
+        check(widgets.itemAt(0) === devicesItem && widgets.itemAt(1) === clockItem
+          && widgets.itemAt(2) === soundItem, "reorder/settings change lost widget identity")
+        check(widgets.itemAt(3) === dividerA && widgets.itemAt(4) === dividerB,
+          "duplicate entries lost their occurrence identity")
+        check(root.created === initialCreated + 1, "insertion recreated existing delegates")
+        check(Array.isArray(soundItem.settings.items)
+          && soundItem.settings.items[1].nested.values[1] === 2, "nested settings changed shape")
+        BarModel.syncEntries(entries, [devices, clock, movedSound])
+        check(widgets.count === 3 && widgets.itemAt(2) === soundItem
+          && widgets.itemAt(1) === clockItem, "removal recreated surviving delegates")
+        BarModel.syncEntries(entries, [devices, {id: "clock", format: "ss"}, movedSound])
+        check(widgets.itemAt(1) === clockItem && clockItem.settings.format === "ss",
+          "settings did not update the existing widget")
+        BarModel.syncEntries(entries, [])
+        check(widgets.count === 0, "empty layout retained delegates")
+        BarModel.syncEntries(entries, ["clock"])
+        check(widgets.count === 1 && widgets.itemAt(0).settings === "clock", "empty layout cannot be populated again")
+        console.log("BAR_LAYOUT_MODEL_OK")
+      } catch (error) {
+        console.error("BAR_LAYOUT_MODEL_FAIL: " + error)
+      }
+      Qt.quit()
+    }
+  }
+}