houseplan-card/docs/testing-notes/mutation-browser-guards.md

Browser guards mutation registry (#659)

This is the reviewed classification of every mutation witness that still needs a browser. The executable limit is 200; mutation-gate --check, npm run inventory and the unit contract all read this same inventory. A new browser guard must be added deliberately under one reason below, and its mutant because must explain the concrete browser-only invariant.

Converted witnesses are not listed here: their registry guard names an explicit node --test suite plus test/mutation-browser-offload.test.mjs, and every converted mutant is run once to prove that the Node witness actually kills it.

Category	Count	Why a browser is still required
Performance threshold	4	The witness measures real browser wall-time or frame work; a pure assertion cannot prove the budget.
Browser harness integrity	4	The mutation breaks page-error, round-trip or page-registration observation in the browser harness itself.
Paint, cascade and layer composition	26	The invariant depends on computed CSS, SVG paint, clipping, stacking or pixels produced by Chromium.
Pointer geometry and trusted interaction	45	The invariant depends on hit testing, pointer capture, touch/keyboard dispatch or live DOM geometry.
Responsive DOM layout	36	The invariant depends on measured element boxes, responsive breakpoints, native/HA dialog shells or focusable target size.
Custom-element and HA browser lifecycle	85	The invariant crosses Lit/custom-element lifecycle, browser storage/events, lazy loading or a complete HA-card state transition.
Total	200 / 200	Growth above the cap fails mutation-gate --check.

Reviewed per-mutant inventory

Performance threshold

The witness measures real browser wall-time or frame work; a pure assertion cannot prove the budget.

• junction-limit-p3-quadratic-again
• junction-limit-p4-bruteforce-again
• wall-draw-full-preflight-again
• wall-draw-wall-artifact-discarded

Browser harness integrity

The mutation breaks page-error, round-trip or page-registration observation in the browser harness itself.

• benchmark-page-verdict-unwatched
• report-page-errors-skips-round-trip
• smoke-guard-blind-to-tail
• smoke-guard-forgets-to-register-pages

Paint, cascade and layer composition

The invariant depends on computed CSS, SVG paint, clipping, stacking or pixels produced by Chromium.

• daycycle-outline-not-promoted
• daycycle-outline-promoted-on-inner-paper
• daycycle-static-outline-promoted-on-inner-paper
• decor-restored-below-room-fills
• device-keyboard-bypasses-click-path
• device-long-value-ellipsis-restored
• device-unavailable-hover-restored
• golden-filled-tunnel-removed
• golden-lamp-out-of-reach
• hatch-static-renderer-untouched
• hatch-stroke-not-scaled
• hatch-zoom-compensation-back
• iso-first-frame-reveals-flat-during-lazy-load
• iso-room-label-44-box-centres-name
• iso-sun-card-drops-occluders
• iso-sun-flat-wedges-remain
• iso-theme-dark-wall-rule-returns
• stage3-w4-device-target-loses-44px-floor
• stage3-w5-runtime-nudge-writes-storage
• stage3-w6-no-borders-keeps-raised-plates
• stage3-w7-sun-state-enters-structural-key
• sun-ray-origin-cache-ignored
• sun-ray-origin-save-forced-inner
• value-static-icon-keeps-live-vacuum
• value-static-icon-keeps-route-warning
• value-static-icon-keeps-vacuum-overlay

Pointer geometry and trusted interaction

The invariant depends on hit testing, pointer capture, touch/keyboard dispatch or live DOM geometry.

• align-guides-exclude-dead-source
• align-point-reads-frozen-snapshot
• decor-default-style-debounce-cut
• decor-default-style-seed-cut
• decor-keyboard-nudge-drops-focus-dialog-guards
• decor-keyboard-nudge-reruns-magnet
• dense-device-hit-browser-skips-painted-priority
• double-fit-bypasses-canonical-fit-all
• furniture-art-editor-adopt-skipped
• furniture-edge-handles-steal-the-corner
• furniture-exterior-surface-removed
• furniture-shift-listeners-not-attached
• furniture-wall-runtime-drops-drag-side
• furniture-wall-runtime-drops-raw-intent
• live-pinch-compositor-demoted-on-active-lit-commit
• opening-dimension-overlay-hidden
• opening-search-hides-none
• opening-search-select-not-wired
• placement-accepts-any-mouse-button
• reorder-skips-materialization
• resize-history-boundary-repair-removed
• resize-label-uses-old-room-gear-centre
• resize-labels-hide-narrow-area
• resize-pointer-capture-removed
• resize-preview-reject-silent
• room-fit-html-overlay-jumps-ahead
• room-fit-pan-release-reaccepted
• room-fit-persists-zoom
• safe-resize-commit-preflight-bypassed
• sections-editor-transition-uses-window-height
• sections-grid-drops-stage-flex-chain
• sections-grid-falls-back-to-viewport-height
• sections-resize-drops-stage-refit-observer
• space-card-decor-capability-change-not-adopted
• space-card-decor-capability-downgrade-does-not-clear-assets
• tab-drag-outlives-the-card
• tab-drag-survives-release-outside
• tab-drag-target-follows-captured-source
• tab-drop-indicator-always-before
• tab-drop-outside-commits-last-target
• tab-reorder-not-persisted
• touch-pinch-marker-hold-rearmed
• touch-pinch-zoom-persists-per-frame
• unavailable-toggle-stays-silent
• wall-draw-rejection-rollback-skipped

Responsive DOM layout

The invariant depends on measured element boxes, responsive breakpoints, native/HA dialog shells or focusable target size.

• dialog-ha-disconnected-reject-reopen-enabled
• dialog-ha-rejected-close-reopen-disabled
• dialog-native-reconnect-recovery-disabled
• dialog-native-surface-stretches-to-viewport
• dialog-native-update-recovery-disabled
• fit-house-hidden-walls-vote
• grid-scale-imperial-roundtrip-drift
• grid-scale-opening-hit-unscaled
• grid-scale-opening-symbol-unscaled
• grid-scale-plan-chrome-unscaled
• grid-scale-static-factor-missing
• header-menu-item-below-44
• header-menu-outside-tap-reaches-plan
• hidden-room-names-compact-svg-fallback
• hidden-room-names-full-svg-fallback
• hidden-room-names-iso-override
• hp-dialog-ignores-flex-content
• panel-readonly-empty-bypasses-write-capability
• phone-editor-close-hidden-with-mode-buttons
• phone-header-at-tablet-width
• phone-header-shows-title
• phone-header-wraps
• static-card-descendants-hit-testable
• summary-dialog-drops-flex-content
• summary-picker-hot-add-stays-filtered
• tab-editing-without-write-access
• toolbar-active-highlight-stops-at-tab
• toolbar-close-back-inside-tab
• toolbar-close-hidden-at-medium-width
• toolbar-close-slot-collapses-outside-editor
• toolbar-close-slot-idle-focusable
• toolbar-close-slot-leaves-mode-group
• toolbar-close-target-below-24
• toolbar-device-count-returns
• toolbar-mode-zoom-gap-regresses
• warm-dialog-drops-transferred-baseline

Custom-element and HA browser lifecycle

The invariant crosses Lit/custom-element lifecycle, browser storage/events, lazy loading or a complete HA-card state transition.

• accepted-marker-rolled-back-by-layout-failure
• area-relocation-clears-whole-history
• area-relocation-loses-position-on-refusal
• backdrop-busy-dismiss-races-decision
• backdrop-downscale-drops-alpha
• backdrop-phase2-falls-back-to-original
• backdrop-probe-always-safe
• barrier-cache-never-invalidated
• camera-anchor-from-presented
• camera-cancel-loses-zoom
• child-readd-clears-parent-tombstone
• cold-view-toggle-delegated-to-runtime
• cold-view-vacuum-mapid-delegated
• color-picker-confirm-click-through
• color-picker-invalid-confirm-latch-removed
• config-updated-event-ignored
• confirm-dialog-loses-alertdialog
• current-rejected-physical-write-keeps-optimistic-wall
• danger-confirm-back-into-the-branch
• danger-confirm-lost-space-request-guard-removed
• danger-confirm-lost-space-transition-cancel-removed
• danger-confirm-uses-last-rendered-language-gate
• danger-confirm-warm-language-guard-removed
• danger-confirm-warm-transition-cancel-removed
• daycycle-programmatic-camera-skips-safe-outline
• device-echo-keeps-local-noncanonical
• device-focus-tooltip-blur-cleanup-removed
• device-focus-tooltip-handler-removed
• device-focus-tooltip-room-hover-overwrites
• device-inbox-batch-rollback
• household-enter-stops-acting
• household-marker-drops-keyboard-reach
• device-markers-rendered-without-keys
• device-pointer-leave-clears-focus-fallback
• device-position-cancel-routed-to-commit
• discovery-reset-writes-a-copy
• editor-neutral-escape-does-not-exit
• empty-space-cleanup-disabled
• fixed-floor-transition-guard-bypassed
• french-locale-wrong-dictionary
• hp-dialog-escape-does-not-close
• junction-limit-baseline-cache-stale
• junction-limit-candidate-fail-open
• junction-limit-write-gate-removed
• locale-failure-toast-dropped
• marker-reject-keeps-optimistic-candidate
• marker-rollback-keeps-enqueue-time-revision
• namespace-loader-returns-english
• near-axis-authoring-snap-bypassed
• onboarding-loader-skips-namespace-ensure
• openings-rendered-without-keys
• plan-only-preview-label-hidden
• plan-room-area-icon-hidden
• plan-room-area-icon-navigates
• plan-upload-client-limit
• plan-upload-guard-original
• plan-upload-reduced-over-limit-staged
• post-write-tail-runs-on-refused-gate
• readonly-view-syncs-new-devices
• render-invalidation-renders-irrelevant-ha
• reopened-room-from-registry-space
• room-accept-leaves-coincident-partitions
• room-gear-second-touch-keeps-drag
• room-settings-click-does-not-open
• room-tooltip-off-skips-pointer-modality
• same-space-room-change-recenters
• space-create-hidden-display-override
• stairs-view-pan-opens-target-floor
• support-invalid-response-leaks-issued-token
• support-stale-preview-response-revives-consent
• support-timeout-claims-success
• vacuum-overlay-back-to-the-dock-space-filter
• volumetric-kiosk-ignores-setting
• view-current-space-aria-removed
• wall-face-apply-skips-overlap-guard
• wallthick-hit-narrowed
• writer-history-skips-finished-chain-normalization
• zigbee-topology-endpoint-cleanup-skipped
• zigbee-topology-endpoint-elevation-removed
• zigbee-topology-hovered-endpoint-elevation-removed
• zigbee-topology-overlay-double-live-projection
• zigbee-topology-overlay-layer-lowered
• zigbee-topology-unknown-casing-gaps-filled
• zigbee-topology-unknown-casing-removed
• zigbee-topology-unrelated-markers-raised