The safety layer: two presses for anything you cannot take back

Claude-Session: https://claude.ai/code/session_01Ms2FbjQy31TVf3CEvQhGM8

README.md

@@ -151,7 +151,7 @@ docs/           Settings reference, and the design specs behind the work
 
 ## Tests
 
-175 of them, under `tests/`. Run the lot, or a subset by pattern:
+176 of them, under `tests/`. Run the lot, or a subset by pattern:
 
 ```sh
 panama test           # everything

config/dot/quickshell/modules/powermenu/PowerButton.qml

@@ -1,8 +1,13 @@
 // One tile in the power menu: big glyph, label underneath.
 //
 // Anything that ends the session arms on the first press and only fires on the
-// second, with the label swapping to "Confirm" — an accidental Ctrl+Alt+Delete
+// second — an accidental Ctrl+Alt+Delete should never be one click away from
-// should never be one click away from losing everything that is open.
+// losing everything that is open.
+//
+// Armed, the tile turns red and names the thing it is about to do ("Power off")
+// rather than saying "Confirm". Six tiles could all say "Confirm"; only one of
+// them is about to take the machine down, and the press that does it should say
+// which one it is.
 
 import QtQuick
 import qs.config
@@ -21,6 +26,13 @@ Rectangle {
 
     readonly property bool armed: confirmTimer.running
 
+    // The tile's own label, said as a sentence rather than as a title: "Power
+    // Off" is the name of a menu entry, "Power off" is the thing the next press
+    // does. Derived, so an entry added to the menu cannot forget to name itself.
+    readonly property string armedLabel: root.label === ""
+        ? "Confirm"
+        : root.label.charAt(0) + root.label.slice(1).toLowerCase()
+
     implicitWidth: 136
     implicitHeight: 136
     radius: Theme.cardRadius + 6
@@ -68,7 +80,7 @@ Rectangle {
 
         Text {
             anchors.horizontalCenter: parent.horizontalCenter
-            text: root.armed ? "Confirm" : root.label
+            text: root.armed ? root.armedLabel : root.label
             color: root.armed ? Theme.danger : Theme.fg
             font.family: Theme.fontFamily
             font.pixelSize: Theme.fontSize

config/dot/quickshell/modules/settings/ConfirmAction.qml

@@ -0,0 +1,81 @@
+// The two-stage destructive confirm, as one component instead of twenty
+// hand-rolled copies. The first press arms ("Verb…", normal tone -- danger
+// never initiates, per SettingsButton's own contract); armed, the row shows
+// Cancel ("Keep") beside the confirming press ("Verb it", danger tone).
+//
+// One armed confirm exists app-wide: the token lives on ShellState, so arming
+// this one disarms whichever other row was armed, on any page. Consumers give
+// a unique actionId, the verb pair, and handle onConfirmed; the component owns
+// the state, the copy shape, and the keyboard path (via SettingsButton).
+//
+//   ConfirmAction {
+//       actionId: "forget-network:" + ssid
+//       armText: "Forget…"          // default: verb + ellipsis
+//       confirmText: "Forget it"
+//       cancelText: "Keep"          // the house cancel word
+//       enabled: !Service.busy
+//       onConfirmed: Service.forget(ssid)
+//   }
+//
+// The armed state is readable (`armed`) so a row can swap its detail line for
+// the consequence-naming sentence while armed -- naming what is lost is the
+// caller's half of the contract; this component only guarantees the two
+// presses happen and the wrong button cannot be the easy one.
+
+import QtQuick
+import qs.config
+import qs.services
+
+Row {
+    id: root
+
+    property string actionId: ""
+    property string armText: "Remove…"
+    property string confirmText: "Remove it"
+    property string cancelText: "Keep"
+    property bool enabled: true
+    signal confirmed
+    signal armedChanged2
+
+    readonly property bool armed: root.actionId !== ""
+        && ShellState.armedConfirm === root.actionId
+
+    spacing: 7
+
+    function disarm(): void {
+        if (root.armed)
+            ShellState.armedConfirm = "";
+    }
+
+    // Leaving the page, or the row vanishing under the armed state, must not
+    // leave a stale token claiming some other future row's identity. Rows more
+    // often hide than unload (an override pill, a conditional card), so the
+    // visibility guard matters as much as the destruction one.
+    Component.onDestruction: root.disarm()
+    onVisibleChanged: if (!root.visible) root.disarm()
+
+    SettingsButton {
+        visible: !root.armed
+        enabled: root.enabled
+        text: root.armText
+        onClicked: ShellState.armedConfirm = root.actionId
+    }
+
+    SettingsButton {
+        visible: root.armed
+        enabled: root.enabled
+        text: root.cancelText
+        onClicked: root.disarm()
+    }
+
+    SettingsButton {
+        visible: root.armed
+        enabled: root.enabled
+        tone: "danger"
+        text: root.confirmText
+        onClicked: {
+            root.disarm();
+            root.confirmed();
+        }
+    }
+}

config/dot/quickshell/modules/settings/DisplayPanelHeader.qml

@@ -104,15 +104,22 @@ Item {
             }
         }
 
+        // Armed, this line stops reporting the current mode and names what
+        // forgetting costs. The consequence used to live in a 400ms tooltip on
+        // the pill, which is not where someone about to press Forget is
+        // looking.
         Text {
             width: parent.width
-            visible: root.meta !== ""
+            visible: root.meta !== "" || forget.armed
-            text: root.meta
+            text: forget.armed
+                ? "Resolution, refresh rate, scale, rotation and color go back to what Panama picks automatically."
+                : root.meta
             color: Theme.fgDim
             font.family: Theme.fontFamily
             font.features: Theme.tabularFigures
             font.pixelSize: Theme.fontSizeSmall
-            elide: Text.ElideRight
+            wrapMode: forget.armed ? Text.WordWrap : Text.NoWrap
+            elide: forget.armed ? Text.ElideNone : Text.ElideRight
         }
     }
 
@@ -136,9 +143,11 @@ Item {
             border.width: 1
             border.color: Theme.alpha(Theme.accent, 0.25)
 
+            // The pill says what the state IS. What Forget costs is said by
+            // the header line while Forget is armed, not hidden in here.
             ToolTip.visible: customHover.hovered
             ToolTip.delay: 400
-            ToolTip.text: "This display uses a setting you chose. Forget returns it to the one Panama ships."
+            ToolTip.text: "This display uses a setting you chose, not the one Panama picks automatically."
 
             Text {
                 id: customLabel
@@ -153,13 +162,17 @@ Item {
             HoverHandler { id: customHover }
         }
 
-        SettingsButton {
+        ConfirmAction {
+            id: forget
+
             anchors.verticalCenter: parent.verticalCenter
             visible: root.overridden
             width: visible ? implicitWidth : 0
-            text: "Forget"
+            actionId: "forget-display:" + root.connector
+            armText: "Forget…"
+            confirmText: "Forget it"
             enabled: root.enabled
-            onClicked: root.forgetRequested()
+            onConfirmed: root.forgetRequested()
         }
     }
 }

config/dot/quickshell/modules/settings/ErrorRow.qml

@@ -0,0 +1,28 @@
+// A failure, reported where it happened. Before this component every page
+// hand-rolled the same stanza with a different headline -- "Problem",
+// "Updates need attention", "The network needs attention" -- and no visual
+// mark distinguishing a failure from any other read-only fact. One shape now:
+//
+//   ErrorRow { message: Updates.lastError }
+//   ErrorRow { message: Vpn.lastError; label: "The VPN needs attention" }
+//
+// The row hides itself while the message is empty, so consumers bind the
+// service's lastError directly and write no visible: line. The message is the
+// service's own sentence -- this component never rewords a failure, only
+// frames it.
+
+import QtQuick
+import qs.config
+
+SettingRow {
+    id: root
+
+    property string message: ""
+    label: "Needs attention"
+
+    visible: root.message !== ""
+    detail: root.message
+    labelColor: Theme.danger
+    controlWidth: 210
+    divider: false
+}

config/dot/quickshell/modules/settings/FirewallPage.qml

@@ -38,6 +38,24 @@ SettingsPage {
     property string pendingInterface: ""
     property string pendingZone: ""
 
+    // The default is the same change with a wider blast radius: it decides for
+    // every connection that does not ask for a zone by name. It used to apply
+    // on the pick, one dropdown below a picker that made you confirm.
+    property string pendingDefaultZone: ""
+
+    // Two armed changes on screen at once is how the wrong one gets pressed.
+    function armInterfaceMove(iface: string, zoneName: string): void {
+        root.pendingDefaultZone = "";
+        root.pendingInterface = iface;
+        root.pendingZone = zoneName;
+    }
+
+    function armDefaultZone(zoneName: string): void {
+        root.pendingInterface = "";
+        root.pendingZone = "";
+        root.pendingDefaultZone = zoneName;
+    }
+
     // The zone being read in the browser. Read-only: this looks at a zone
     // without applying it to anything.
     property string browsingZone: ""
@@ -416,10 +434,7 @@ SettingsPage {
                     options: root.zoneOptions
                     current: placement.zone
                     divider: !placement.pending
-                    onPicked: value => {
+                    onPicked: value => root.armInterfaceMove(placement.iface, String(value))
-                        root.pendingInterface = placement.iface;
-                        root.pendingZone = String(value);
-                    }
                 }
 
                 SettingRow {
@@ -482,7 +497,45 @@ SettingsPage {
             enabled: !Firewall.busy
             options: root.zoneOptions
             current: Firewall.defaultZone
-            onPicked: value => Firewall.setDefaultZone(String(value))
+            divider: root.pendingDefaultZone === ""
+            onPicked: value => root.armDefaultZone(String(value))
+        }
+
+        SettingRow {
+            width: parent.width
+            visible: root.pendingDefaultZone !== ""
+            label: "Make " + root.pendingDefaultZone + " the default?"
+            // What moves is named the way the per-interface confirm names its
+            // interface: not "the default changes", but which machines end up
+            // deciding differently because of it.
+            detail: "Every connection firewalld has not placed in a zone of its "
+                + "own follows the default — each one leaves " + Firewall.defaultZone
+                + " for " + root.pendingDefaultZone
+                + ", and so does every network joined from now on."
+            controlWidth: 240
+
+            Row {
+                anchors.right: parent.right
+                anchors.verticalCenter: parent.verticalCenter
+                spacing: 8
+
+                SettingsButton {
+                    text: "Keep " + Firewall.defaultZone
+                    enabled: !Firewall.busy
+                    onClicked: root.pendingDefaultZone = ""
+                }
+
+                SettingsButton {
+                    text: "Change it"
+                    tone: "danger"
+                    enabled: !Firewall.busy
+                    onClicked: {
+                        const target = root.pendingDefaultZone;
+                        root.pendingDefaultZone = "";
+                        Firewall.setDefaultZone(target);
+                    }
+                }
+            }
         }
 
         // ── The zone browser ─────────────────────────────────────────────────

config/dot/quickshell/modules/settings/NotMeasuredRow.qml

@@ -0,0 +1,26 @@
+// The honest empty state: a fact the page cannot read right now, with the
+// reason it cannot. The house rule is that "not measured" is always followed
+// by "because" -- a bare dash invites the reader to assume zero, and zero is
+// a measurement.
+//
+//   NotMeasuredRow { because: "The desktop portal's permission store is not answering, so what has asked for this cannot be read." }
+//   NotMeasuredRow { label: "Not read yet"; because: "Reading what the battery firmware has recorded." }
+//
+// `because` is required in spirit: the row renders without one, but a consumer
+// leaving it empty is exactly the dishonesty this component exists to prevent,
+// and the idiom contract greps for it.
+
+import QtQuick
+import qs.config
+
+SettingRow {
+    id: root
+
+    property string because: ""
+    label: "Not measured"
+
+    detail: root.because
+    labelColor: Theme.fgDim
+    controlWidth: 210
+    divider: false
+}

config/dot/quickshell/modules/settings/PrintersPage.qml

@@ -251,11 +251,16 @@ SettingsPage {
 
                 width: parent.width
                 label: String(jobRow.modelData.name ?? "Untitled")
-                detail: String(jobRow.modelData.printer ?? "") + " · "
+                // Armed, the row makes the Hold/Cancel distinction the service
+                // was built around: holding keeps the job, cancelling throws it
+                // away and the document has to be sent from the app again.
+                detail: cancelJob.armed
+                    ? "The job is thrown away — printing it means sending it from the app again. Hold keeps it in the queue instead."
+                    : String(jobRow.modelData.printer ?? "") + " · "
                     + String(jobRow.modelData.state ?? "")
                     + (Number(jobRow.modelData.pages ?? 0) > 0
                         ? " · " + jobRow.modelData.pages + " pages" : "")
-                controlWidth: 175
+                controlWidth: 265
                 divider: jobRow.index < Printers.jobs.length - 1
 
                 Row {
@@ -275,11 +280,18 @@ SettingsPage {
                             : Printers.hold(Number(jobRow.modelData.id))
                     }
 
-                    SettingsButton {
+                    ConfirmAction {
+                        id: cancelJob
+
                         anchors.verticalCenter: parent.verticalCenter
-                        text: "Cancel"
+                        actionId: "cancel-job:" + String(jobRow.modelData.id ?? "")
+                        armText: "Cancel…"
+                        confirmText: "Cancel it"
+                        // Not "Keep": the job is not being kept in a drawer, it
+                        // carries on out of the printer.
+                        cancelText: "Keep printing"
                         enabled: !Printers.busy
-                        onClicked: Printers.cancel(Number(jobRow.modelData.id))
+                        onConfirmed: Printers.cancel(Number(jobRow.modelData.id))
                     }
                 }
             }

config/dot/quickshell/modules/settings/SettingRow.qml

@@ -7,6 +7,9 @@ Item {
     default property alias trailingData: trailing.data
     property string icon: ""
     property string label: ""
+    // The headline's colour. Foreground for every ordinary row; ErrorRow sets
+    // it to Theme.danger so a failure reads as one at a glance.
+    property color labelColor: Theme.fg
     property string detail: ""
     property string value: ""
     property bool divider: true
@@ -70,7 +73,7 @@ Item {
         Text {
             width: parent.width
             text: root.label
-            color: Theme.fg
+            color: root.labelColor
             font.family: Theme.fontFamily
             font.pixelSize: Theme.fontSize
             font.weight: Font.Medium

config/dot/quickshell/modules/settings/SettingsButton.qml

@@ -17,6 +17,31 @@ Rectangle {
     implicitHeight: 31
     radius: 9
     opacity: enabled ? 1 : 0.45
+
+    // The keyboard half of this component's own contract. Eleven files used
+    // to bolt these on by hand while the other hundred-odd instantiations --
+    // including every confirming button in every destructive flow -- were
+    // pointer-only. The button carries them itself now, so a consumer cannot
+    // forget them.
+    activeFocusOnTab: root.enabled
+    Accessible.role: Accessible.Button
+    Accessible.name: root.text
+    Accessible.focusable: root.enabled
+    Accessible.focused: root.activeFocus
+    Accessible.onPressAction: root.clicked()
+    Keys.onReturnPressed: root.clicked()
+    Keys.onEnterPressed: root.clicked()
+    Keys.onSpacePressed: root.clicked()
+
+    Rectangle {
+        anchors.fill: parent
+        anchors.margins: -3
+        radius: parent.radius + 3
+        visible: root.activeFocus
+        color: "transparent"
+        border.width: 2
+        border.color: Theme.accentSecondary
+    }
     color: {
         if (tone === "accent")
             return mouse.containsMouse ? Theme.mix(Theme.accent, Theme.fg, 0.12) : Theme.accent;

config/dot/quickshell/modules/settings/SharingPage.qml

@@ -157,15 +157,32 @@ SettingsPage {
             onTriggered: Sharing.setRdpCredentials(Quickshell.env("USER") || "")
         }
 
-        ActionRow {
+        SettingRow {
+            id: forgetCredentials
+
+            width: parent.width
             visible: Sharing.remoteDesktop?.available === true
                 && Sharing.remoteDesktop?.hasCredentials === true
             label: "Forget the stored credentials"
-            detail: "Remote desktop cannot be turned on again until new ones are set"
+            // Armed, the row names the loss rather than the state: the keyring
-            action: "Clear"
+            // entry goes, and the only way back is the terminal flow above.
-            enabled: !Sharing.busy
+            detail: forgetCredentialsConfirm.armed
+                ? "The user name and password are deleted from the login keyring. Remote desktop stays off until you set new ones in a terminal."
+                : "Remote desktop cannot be turned on again until new ones are set"
+            controlWidth: 200
             divider: false
-            onTriggered: Sharing.clearRdpCredentials()
+
+            ConfirmAction {
+                id: forgetCredentialsConfirm
+
+                anchors.right: parent.right
+                anchors.verticalCenter: parent.verticalCenter
+                actionId: "forget-rdp-credentials"
+                armText: "Forget…"
+                confirmText: "Forget them"
+                enabled: !Sharing.busy
+                onConfirmed: Sharing.clearRdpCredentials()
+            }
         }
     }
 

config/dot/quickshell/modules/settings/SnapshotsPage.qml

@@ -257,7 +257,15 @@ SettingsPage {
                         // what to rely on later.
                         icon: pointRow.modelData.kept ? "\u{F0A22}" : "\u{F0954}"
                         label: String(pointRow.modelData.date ?? "")
-                        detail: String(pointRow.modelData.description ?? "")
+                        // Armed, the row names the loss instead of describing
+                        // the snapshot: this is the only record of what these
+                        // files looked like then, and deleting it is the one
+                        // thing on this page nothing else can undo.
+                        detail: pointRow.confirming
+                            ? "The only copy of these files as of "
+                              + String(pointRow.modelData.date ?? "this point in time")
+                              + " is deleted."
+                            : String(pointRow.modelData.description ?? "")
                             + " · #" + pointRow.modelData.number
                             + (pointRow.modelData.kept ? " · kept" : "")
                             + (pointRow.browsingThis ? " · open below" : "")

config/dot/quickshell/modules/settings/SshKeysPage.qml

@@ -347,15 +347,27 @@ SettingsPage {
 
                 width: parent.width
                 label: String(heldRow.modelData.name ?? "")
-                detail: String(heldRow.modelData.fingerprint ?? "")
+                // Armed, the row stops showing the fingerprint and says what
-                controlWidth: 110
+                // the confirming press will actually do -- including the case
+                // where it will do nothing, which is owed BEFORE the press
+                // rather than as an error afterwards.
+                detail: removeHeld.armed
+                    ? (SshKeys.durableRemoval
+                        ? "The agent stops offering this key until it is added again. The key file in ~/.ssh is untouched."
+                        : "This agent lists every key in ~/.ssh, so it will refuse: removal here does not stick. Move the key out of ~/.ssh instead.")
+                    : String(heldRow.modelData.fingerprint ?? "")
+                controlWidth: 190
+
+                ConfirmAction {
+                    id: removeHeld
 
-                SettingsButton {
                     anchors.right: parent.right
                     anchors.verticalCenter: parent.verticalCenter
-                    text: "Remove"
+                    actionId: "agent-remove:" + String(heldRow.modelData.path ?? "")
+                    armText: "Remove…"
+                    confirmText: "Remove it"
                     enabled: !SshKeys.busy
-                    onClicked: SshKeys.removeFromAgent(String(heldRow.modelData.path ?? ""))
+                    onConfirmed: SshKeys.removeFromAgent(String(heldRow.modelData.path ?? ""))
                 }
             }
         }

config/dot/quickshell/modules/settings/UsersPage.qml

@@ -276,16 +276,34 @@ SettingsPage {
                         }
                     }
 
-                    SettingsButton {
+                    ConfirmAction {
+                        id: removePicture
+
                         visible: UserAccounts.avatarUrl !== ""
-                        text: "Remove"
+                        actionId: "remove-avatar"
+                        armText: "Remove…"
+                        confirmText: "Remove it"
                         enabled: !UserAccounts.busy
-                        onClicked: {
+                        onConfirmed: {
                             root.pictureOpen = false;
                             UserAccounts.removeIcon();
                         }
                     }
                 }
+
+                // The consequence, said before the confirming press: this
+                // deletes the file accountsservice keeps, so the picture is
+                // gone from the lock screen and every other account surface,
+                // not merely from this page.
+                Text {
+                    width: parent.width
+                    visible: removePicture.armed
+                    text: "The picture is deleted from your account — the lock screen and everywhere else showing it fall back to your initial."
+                    color: Theme.fgDim
+                    font.family: Theme.fontFamily
+                    font.pixelSize: Theme.fontSizeSmall
+                    wrapMode: Text.WordWrap
+                }
             }
         }
 

config/dot/quickshell/modules/settings/qmldir

@@ -37,6 +37,9 @@ SettingRow 1.0 SettingRow.qml
 SettingsCard 1.0 SettingsCard.qml
 SettingsNote 1.0 SettingsNote.qml
 SettingsButton 1.0 SettingsButton.qml
+ConfirmAction 1.0 ConfirmAction.qml
+ErrorRow 1.0 ErrorRow.qml
+NotMeasuredRow 1.0 NotMeasuredRow.qml
 SettingsShell 1.0 SettingsShell.qml
 SettingsSidebar 1.0 SettingsSidebar.qml
 SettingsToggle 1.0 SettingsToggle.qml

config/dot/quickshell/services/ShellState.qml

@@ -142,4 +142,11 @@ Singleton {
     // Set by Dock.qml so the bar can avoid fighting it for pointer grabs, and
     // read by the capture overlay so the dock isn't in the screenshot.
     property bool dockRevealed: false
+
+    // Exactly one destructive confirmation may be armed at a time, app-wide --
+    // "two armed destructive actions on screen at once is how the wrong one
+    // gets pressed" (SyncPage wrote that down for its own card; ConfirmAction
+    // enforces it for everyone). The token is owned by whichever ConfirmAction
+    // armed it; arming another disarms the first.
+    property string armedConfirm: ""
 }

tests/quickshell/settings-idiom-contract

@@ -0,0 +1,93 @@
+#!/usr/bin/env bash
+
+# The safety idioms are only worth having if a refactor cannot quietly drop
+# them. This pins the Tier-1 layer:
+#
+#   1. SettingsButton carries its own keyboard contract (Tab stop, Return /
+#      Enter / Space, Accessible role, focus ring) -- the reason no consumer
+#      hand-rolls those any more.
+#   2. ConfirmAction exists, is registered, and every instantiation names an
+#      actionId; the one-armed-at-a-time token it arbitrates through lives on
+#      ShellState. An anonymous ConfirmAction shares "" with every other
+#      anonymous one, which arms them all at once.
+#   3. ErrorRow instantiations bind a message, and NotMeasuredRow
+#      instantiations say `because:` -- a bare "Not measured" invites the
+#      reader to assume zero, and zero is a measurement.
+
+set -uo pipefail
+
+repo_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
+qs="$repo_dir/config/dot/quickshell"
+
+fail() { printf 'settings idiom contract: %s\n' "$1" >&2; exit 1; }
+[[ -r "$qs/modules/settings/SettingsButton.qml" ]] || fail "missing SettingsButton.qml"
+
+python3 - "$qs" <<'PY'
+import re, sys, pathlib
+qs = pathlib.Path(sys.argv[1])
+settings = qs / 'modules' / 'settings'
+problems = []
+
+# 1. The button's own keyboard contract.
+button = (settings / 'SettingsButton.qml').read_text()
+for needle, why in [
+    ('activeFocusOnTab', 'no Tab stop'),
+    ('Keys.onReturnPressed', 'Return does nothing'),
+    ('Keys.onSpacePressed', 'Space does nothing'),
+    ('Accessible.role', 'invisible to screen readers'),
+    ('Theme.accentSecondary', 'no focus ring'),
+]:
+    if needle not in button:
+        problems.append(f'SettingsButton.qml: {needle} gone -- {why}')
+
+# 2. ConfirmAction registered, arbitrated through ShellState, always named.
+qmldir = (settings / 'qmldir').read_text()
+for component in ('ConfirmAction', 'ErrorRow', 'NotMeasuredRow'):
+    if not re.search(rf'^{component} ', qmldir, re.M):
+        problems.append(f'qmldir: {component} unregistered -- pages referencing it fail to load')
+
+confirm = (settings / 'ConfirmAction.qml').read_text()
+if 'ShellState.armedConfirm' not in confirm:
+    problems.append('ConfirmAction.qml: not arbitrated through ShellState.armedConfirm -- two rows can be armed at once')
+shellstate = (qs / 'services' / 'ShellState.qml').read_text()
+if 'armedConfirm' not in shellstate:
+    problems.append('ShellState.qml: armedConfirm token gone -- ConfirmAction has nothing to arbitrate through')
+
+# 3. Instantiation-shape checks. A component use spans the braces that follow
+# it; requiring the property inside that span is a cheap parse that has caught
+# every real miss so far.
+def block_after(text, start):
+    depth, i = 0, text.index('{', start)
+    for j in range(i, len(text)):
+        if text[j] == '{': depth += 1
+        elif text[j] == '}':
+            depth -= 1
+            if depth == 0: return text[i:j]
+    return text[i:]
+
+REQUIRED = {'ConfirmAction': 'actionId', 'ErrorRow': 'message', 'NotMeasuredRow': 'because'}
+for page in sorted(qs.rglob('*.qml')):
+    if page.name in ('ConfirmAction.qml', 'ErrorRow.qml', 'NotMeasuredRow.qml'):
+        continue
+    text = page.read_text()
+    for component, prop in REQUIRED.items():
+        for m in re.finditer(rf'\b{component}\s*\{{', text):
+            if not re.search(rf'\b{prop}\s*:', block_after(text, m.start())):
+                problems.append(f'{page.name}: {component} without {prop}:')
+
+if problems:
+    print(f"settings idiom contract: {len(problems)} problem(s)")
+    for p in problems: print("  -", p)
+    sys.exit(1)
+
+uses = {c: 0 for c in REQUIRED}
+for page in qs.rglob('*.qml'):
+    if page.name in ('ConfirmAction.qml', 'ErrorRow.qml', 'NotMeasuredRow.qml'):
+        continue
+    text = page.read_text()
+    for c in uses:
+        uses[c] += len(re.findall(rf'\b{c}\s*\{{', text))
+print("settings idiom contract: ok ("
+      + ", ".join(f"{n} {c}" for c, n in uses.items())
+      + ", every one carries its required property)")
+PY