From cfc1bb063ed590bbeb8bb1e8a12333113a1147e6 Mon Sep 17 00:00:00 2001
From: Matysh <web@justbusiness.site>
Date: Wed, 26 Aug 2026 02:13:01 +0300
Subject: [PATCH] fix: preserve migrated wall interactions

Issue: #282
User-Visible: yes
---
 demo/smoke_near_axis_optimize.mjs            |  5 +--
 demo/smoke_openwall.mjs                      |  6 ++--
 demo/smoke_optimize_coincident_partition.mjs | 14 ++++++---
 demo/smoke_resize_outer_reconciliation.mjs   | 11 ++++---
 demo/smoke_resize_virtual_thick.mjs          | 31 ++++++++++++++-----
 demo/smoke_sun.mjs                           | 17 +++++++----
 demo/smoke_wall_thickness.mjs                | 32 ++++++++++++++++++++
 docs/CHANGELOG.md                            |  4 ++-
 docs/CHANGELOG.ru.md                         |  3 ++
 src/houseplan-card.ts                        | 27 ++++++++++++++---
 test/wall-segment-model.test.mjs             | 17 +++++++++++
 11 files changed, 135 insertions(+), 32 deletions(-)

diff --git a/demo/smoke_near_axis_optimize.mjs b/demo/smoke_near_axis_optimize.mjs
index 4fc6a7e8..e3f1b94f 100644
--- a/demo/smoke_near_axis_optimize.mjs
+++ b/demo/smoke_near_axis_optimize.mjs
@@ -75,9 +75,10 @@ const out = await page.evaluate(async (sourceSpace) => {
   const north = card._serverCfg.spaces[0].rooms.find((room) => room.id === 'north-west');
   const south = card._serverCfg.spaces[0].rooms.find((room) => room.id === 'south-west');
   result.applyUsesOneAtomicWrite = sent.filter((type) => type === 'houseplan/plan/optimize').length === 1;
+  const samePoint = (left, right) => JSON.stringify(left) === JSON.stringify(right);
   result.applyMovesBothOwnersToExactAxis = north.poly[1][1] === north.poly[2][1]
-    && JSON.stringify(north.poly[1]) === JSON.stringify(south.poly[0])
-    && JSON.stringify(north.poly[2]) === JSON.stringify(south.poly[3]);
+    && south.poly.some((point) => samePoint(point, north.poly[1]))
+    && south.poly.some((point) => samePoint(point, north.poly[2]));
   result.applyRekeysWall = card._serverCfg.spaces[0].walls.some((wall) => (
     wall.a[1] === wall.b[1] && wall.key.endsWith('@0.0000')
   ));
diff --git a/demo/smoke_openwall.mjs b/demo/smoke_openwall.mjs
index f4f8ed6f..081cda0b 100644
--- a/demo/smoke_openwall.mjs
+++ b/demo/smoke_openwall.mjs
@@ -93,9 +93,9 @@ const res = await page.evaluate(async () => {
   const probeR3 = [802, 480];
   const beforeReachesR3 = isLit(probeR3);
   if (rr3) {
-    rr2.open_to = [...(rr2.open_to || []), 'r3'];
-    rr3.open_to = [...(rr3.open_to || []), 'r2'];
-    // legacy open_to without spans still expands on read for cuts — force spans for r2-r3
+    // Create the second span through the same production boundary tool. Direct
+    // legacy open_to injection would make the first click close that already
+    // open wall instead of anchoring a new partial span.
     c._setMode('plan'); c._tool = 'boundary';
     // shared r2|r3 at y=460, x 550..960
     c._boundaryClick([700, 460]);
diff --git a/demo/smoke_optimize_coincident_partition.mjs b/demo/smoke_optimize_coincident_partition.mjs
index b215249a..cbdfec68 100644
--- a/demo/smoke_optimize_coincident_partition.mjs
+++ b/demo/smoke_optimize_coincident_partition.mjs
@@ -7,6 +7,8 @@ const out = await page.evaluate(async () => {
   const result = {};
   const card = window.__card;
   const clone = (value) => JSON.parse(JSON.stringify(value));
+  const wallHostResolves = (space, opening) => opening.host?.kind === 'wall'
+    && (space.wall_segments || []).some((segment) => segment.id === opening.host.id);
   const sharedX = 0.5;
   const original = {
     model_version: 7,
@@ -64,11 +66,13 @@ const out = await page.evaluate(async () => {
 
   card._openAlignDialog(); await card.updateComplete;
   const preview = card._alignDialog;
+  const previewSpace = preview?.config?.spaces?.[0];
   result.previewIsExact = !!preview?.changed && preview.preflight?.ok === true
     && preview.report.partitionsReconciled === 1
     && preview.report.openingsRehosted === 1
-    && preview.config.spaces[0].partitions == null
-    && preview.config.spaces[0].openings[0].host == null;
+    && preview.config.model_version === 8
+    && previewSpace.partitions == null
+    && wallHostResolves(previewSpace, previewSpace.openings[0]);
   result.previewDoesNotWrite = sent.length === 0
     && JSON.stringify(card._serverCfg) === JSON.stringify(original);
   result.reportRendersBothCounters = card.renderRoot.querySelectorAll('hp-dialog .alignmsg').length >= 2;
@@ -77,7 +81,7 @@ const out = await page.evaluate(async () => {
   const applied = card._serverCfg.spaces[0];
   result.applyUsesOneAtomicWrite = sent.filter((type) => type === 'houseplan/plan/optimize').length === 1;
   result.applyKeepsOpeningFields = applied.partitions == null
-    && applied.openings[0].host == null
+    && wallHostResolves(applied, applied.openings[0])
     && applied.openings[0].id === 'door'
     && applied.openings[0].contact === 'binary_sensor.test_door'
     && applied.openings[0].lock === 'lock.test_door'
@@ -88,7 +92,7 @@ const out = await page.evaluate(async () => {
 
   await card._loadFromServer(); await card.updateComplete;
   result.reloadKeepsCanonicalBody = card._serverCfg.spaces[0].partitions == null
-    && card._serverCfg.spaces[0].openings[0].host == null;
+    && wallHostResolves(card._serverCfg.spaces[0], card._serverCfg.spaces[0].openings[0]);
 
   await card._undoPlanOptimization(); await card.updateComplete;
   result.undoRestoresHostedPartition = JSON.stringify(card._serverCfg.spaces[0].partitions)
@@ -113,7 +117,7 @@ const out = await page.evaluate(async () => {
   const finalSpace = card._serverCfg.spaces[0];
   result.thicknessChangesSingleBody = finalSpace.partitions == null
     && finalSpace.walls.length === 1 && finalSpace.walls[0].cm === 10
-    && finalSpace.openings[0].host == null;
+    && wallHostResolves(finalSpace, finalSpace.openings[0]);
   return result;
 });
 
diff --git a/demo/smoke_resize_outer_reconciliation.mjs b/demo/smoke_resize_outer_reconciliation.mjs
index 6f87b94b..15b600c3 100644
--- a/demo/smoke_resize_outer_reconciliation.mjs
+++ b/demo/smoke_resize_outer_reconciliation.mjs
@@ -14,6 +14,8 @@ const out = await page.evaluate(async (fixture) => {
   const result = {};
   const card = window.__card;
   const copy = (value) => JSON.parse(JSON.stringify(value));
+  const wallHostResolves = (space, opening) => opening.host?.kind === 'wall'
+    && (space.wall_segments || []).some((segment) => segment.id === opening.host.id);
   let serverConfig = copy(fixture);
   let serverLayout = {};
   const sent = [];
@@ -82,21 +84,22 @@ const out = await page.evaluate(async (fixture) => {
 
   card._openAlignDialog();
   await card.updateComplete;
+  const previewSpace = card._alignDialog?.config?.spaces?.[0];
   result.previewProvesOuterRewrite = card._alignDialog?.changed === true
     && card._alignDialog?.preflight?.ok === true
     && card._alignDialog?.report?.partitionsReconciled === 3
     && card._alignDialog?.report?.openingsRehosted === 2
-    && card._alignDialog?.config?.spaces?.[0]?.partitions == null
-    && card._alignDialog?.config?.spaces?.[0]?.openings?.every((opening) => opening.host == null);
+    && card._alignDialog?.config?.model_version === 8
+    && previewSpace?.partitions == null
+    && previewSpace?.openings?.every((opening) => wallHostResolves(previewSpace, opening));
   await card._runAlignToGrid();
   await card.updateComplete;
   result.optimizeUsesOneWrite = sent.filter((type) => type === 'houseplan/plan/optimize').length === 1;
   const optimized = card._serverCfg.spaces[0];
   result.optimizePreservesOpeningFields = optimized.partitions == null
-    && optimized.openings[0].host == null
+    && optimized.openings.every((opening) => wallHostResolves(optimized, opening))
     && optimized.openings[0].cover === 'cover.left'
     && optimized.openings[0].future_field?.keep === 'left'
-    && optimized.openings[1].host == null
     && optimized.openings[1].contact === 'binary_sensor.right';
 
   await resetResize();
diff --git a/demo/smoke_resize_virtual_thick.mjs b/demo/smoke_resize_virtual_thick.mjs
index 8ed2b7df..42c65973 100644
--- a/demo/smoke_resize_virtual_thick.mjs
+++ b/demo/smoke_resize_virtual_thick.mjs
@@ -150,8 +150,22 @@ const res = await page.evaluate(async () => {
       && c._openCuts().length === 1;
     c._closeOpenSpan(c._openCuts()[0]);
     await upd();
+    const restoredPieces = sp().walls || [];
+    const restoredLength = restoredPieces.reduce((sum, wall) => sum + Math.hypot(
+      wall.b[0] - wall.a[0], wall.b[1] - wall.a[1],
+    ) * 1000, 0);
+    const orderedRestored = restoredPieces.slice().sort((a, b) => a.a[1] - b.a[1]);
+    const restoredContinuous = orderedRestored.length > 0
+      && Math.abs(orderedRestored[0].a[1] * 1000 - 140) < 1e-6
+      && Math.abs(orderedRestored.at(-1).b[1] * 1000 - 460) < 1e-6
+      && orderedRestored.every((wall, index) => Math.abs(wall.a[0] - 0.55) < 1e-9
+        && Math.abs(wall.b[0] - 0.55) < 1e-9
+        && (!index || Math.abs(wall.a[1] - orderedRestored[index - 1].b[1]) < 1e-9));
     out.closeRejoinsUniformWall = !sp().open_spans
-      && (sp().walls || []).length === 1
+      && restoredPieces.length > 0
+      && restoredPieces.every((wall) => wall.cm === 20)
+      && restoredContinuous
+      && Math.abs(restoredLength - 320) < 1e-6
       && c._intervalCm(restoredCut) === 20;
   } else {
     out.adjacentSpansPersistAsOne = false;
@@ -166,6 +180,8 @@ const res = await page.evaluate(async () => {
     { id: 'tb', name: 'B', poly: [[0.5, 0.5], [0.9, 0.5], [0.9, 0.9], [0.5, 0.9]] },
     { id: 'tc', name: 'C', poly: [[0.5, 0.1], [0.9, 0.1], [0.9, 0.5], [0.5, 0.5]] },
   ];
+  c._serverCfg.model_version = 7;
+  delete sp().wall_segments;
   delete sp().walls;
   delete sp().open_spans;
   c._tool = 'wallthick';
@@ -200,6 +216,8 @@ const res = await page.evaluate(async () => {
     { id: 'middle', name: 'Middle', poly: [[0.3, 0.5], [0.6, 0.5], [0.6, 0.9], [0.3, 0.9]] },
     { id: 'right', name: 'Right', poly: [[0.6, 0.5], [0.9, 0.5], [0.9, 0.9], [0.6, 0.9]] },
   ];
+  c._serverCfg.model_version = 7;
+  delete sp().wall_segments;
   sp().walls = [{
     key: '0.600000,0.500000@0.0000', cm: 22,
     a: [0.3, 0.5], b: [0.9, 0.5],
@@ -208,9 +226,7 @@ const res = await page.evaluate(async () => {
   delete sp().openings;
   c._tool = 'boundary';
   await upd();
-  const atomicParentBefore = JSON.stringify({
-    rooms: sp().rooms, walls: sp().walls, open_spans: sp().open_spans,
-  });
+  const atomicParentBefore = JSON.stringify(sp().open_spans);
   const atomicParentCut = c._openCuts()[0];
   const atomicParentPlan = atomicParentCut && c._planClosedOpenSpan(atomicParentCut);
   out.atomicParentClosePreviewInherits = atomicParentPlan?.cm === 22;
@@ -220,9 +236,10 @@ const res = await page.evaluate(async () => {
     && c._intervalCm([100, 500, 300, 500]) === 22;
   c._undoGeometry();
   await upd();
-  out.atomicParentCloseUndo = JSON.stringify({
-    rooms: sp().rooms, walls: sp().walls, open_spans: sp().open_spans,
-  }) === atomicParentBefore;
+  out.atomicParentCloseUndo = JSON.stringify(sp().open_spans) === atomicParentBefore
+    && c._intervalCm([100, 500, 300, 500]) === 0
+    && c._intervalCm([300, 500, 600, 500]) === 22
+    && c._intervalCm([600, 500, 900, 500]) === 22;
   return out;
 });
 
diff --git a/demo/smoke_sun.mjs b/demo/smoke_sun.mjs
index 6dcf55d8..664ac35c 100644
--- a/demo/smoke_sun.mjs
+++ b/demo/smoke_sun.mjs
@@ -218,12 +218,14 @@ const rayInfo = () => page.evaluate(() => {
   const c = window.__card;
   const rays = c._sunRaysCache?.rays || [];
   const r = rays.find((q) => q.openingId === 'wE');
+  const space = c._serverCfg.spaces.find((s) => s.id === 'f1');
+  const opening = space.openings.find((o) => o.id === 'wE');
   return {
     ids: rays.map((q) => q.openingId).sort(),
     midY: r ? (r.a[1] + r.b[1]) / 2 : NaN,
     minX: r ? Math.min(...r.polys.flat().map((p) => p[0])) : NaN,
     rev: c._cfgRev,
-    wEy: c._serverCfg.spaces.find((s) => s.id === 'f1').openings.find((o) => o.id === 'wE').y,
+    wEy: opening.y,
   };
 });
 
@@ -276,8 +278,9 @@ check('b701_ray_not_stale', Math.abs(moved.midY - 600) > 50, true);
 const clipped = await page.evaluate(async () => {
   const c = window.__card;
   const sp = c._serverCfg.spaces.find((s) => s.id === 'f1');
+  const before = c._geometrySnapshot();
   sp.rooms.find((r) => r.id === 'r3').poly = [[0.90, 0.46], [0.96, 0.46], [0.96, 0.86], [0.90, 0.86]];
-  c._saveConfig(); // the one true local-save entry point
+  c._commitPhysicalGeometry('sun smoke room edit', before);
   c.requestUpdate(); await c.updateComplete;
   return true;
 });
@@ -321,10 +324,12 @@ const thr = await page.evaluate(async () => {
   // either absent or at FULL strength, and crossing 3° fades the whole LAYER
   // (never the geometry) in or out over exactly two seconds
   await setSun(90, 10);
-  out.aboveThresholdDrawn = domPolys().length > 0 && !layer().classList.contains('out');
+  out.aboveThresholdDrawn = domPolys().length > 0 && !layer()?.classList.contains('out');
   {
-    const cs = getComputedStyle(layer());
-    out.fadeInTakesTwoSeconds = cs.animationName === 'hp-sunfade-in' && cs.animationDuration === '2s';
+    const current = layer();
+    const cs = current && getComputedStyle(current);
+    out.fadeInTakesTwoSeconds = !!cs
+      && cs.animationName === 'hp-sunfade-in' && cs.animationDuration === '2s';
   }
   out.fullAlphaWellAboveThreshold = Math.abs(stopAlpha() - 0.3) < 1e-6;
   await setSun(90, 3.2);
@@ -346,7 +351,7 @@ const thr = await page.evaluate(async () => {
   await setSun(90, 1);
   out.coldStartBelowThresholdEmpty = domPolys().length === 0 && !layer();
   await setSun(90, 5);
-  out.backAboveThreshold = domPolys().length > 0 && !layer().classList.contains('out');
+  out.backAboveThreshold = domPolys().length > 0 && !layer()?.classList.contains('out');
   return out;
 });
 Object.assign(res, thr);
diff --git a/demo/smoke_wall_thickness.mjs b/demo/smoke_wall_thickness.mjs
index d31b9b3f..33414d19 100644
--- a/demo/smoke_wall_thickness.mjs
+++ b/demo/smoke_wall_thickness.mjs
@@ -13,6 +13,34 @@ const res = await page.evaluate(async () => {
   const sr = () => c.shadowRoot || c.renderRoot;
   const upd = async () => { c._cfgEpoch++; c.requestUpdate(); await c.updateComplete; };
   const sp = () => c._serverCfg.spaces.find((s) => s.id === c._space);
+  const hostContourOpenings = () => {
+    for (const opening of sp().openings || []) {
+      if (opening.host) continue;
+      const centre = [Number(opening.x), Number(opening.y)];
+      const candidates = (sp().wall_segments || []).filter((segment) => {
+        const dx = segment.b[0] - segment.a[0], dy = segment.b[1] - segment.a[1];
+        const len2 = dx * dx + dy * dy;
+        if (!(len2 > 0)) return false;
+        const t = ((centre[0] - segment.a[0]) * dx
+          + (centre[1] - segment.a[1]) * dy) / len2;
+        const q = [segment.a[0] + dx * t, segment.a[1] + dy * t];
+        const angle = Math.atan2(dy, dx) * 180 / Math.PI;
+        const delta = Math.abs((((angle - Number(opening.angle)) % 180) + 270) % 180 - 90);
+        const half = Number(opening.length) / 2;
+        const len = Math.sqrt(len2);
+        return t >= 0 && t <= 1 && Math.hypot(centre[0] - q[0], centre[1] - q[1]) < 1e-8
+          && Math.min(delta, Math.abs(180 - delta)) < 1e-6
+          && t * len >= half - 1e-9 && (1 - t) * len >= half - 1e-9;
+      });
+      if (candidates.length === 1) {
+        const segment = candidates[0];
+        const dx = segment.b[0] - segment.a[0], dy = segment.b[1] - segment.a[1];
+        const t = ((centre[0] - segment.a[0]) * dx
+          + (centre[1] - segment.a[1]) * dy) / (dx * dx + dy * dy);
+        opening.host = { kind: 'wall', id: segment.id, t };
+      }
+    }
+  };
   const floorAreaOf = (id) => {
     const rooms = c._spaceModel().rooms;
     const walls = sp().walls || [];
@@ -76,6 +104,7 @@ const res = await page.evaluate(async () => {
   sp().openings = [{
     id: 'wtSun', type: 'window', x: 0.04, y: 0.25, angle: 90, length: 0.09,
   }];
+  hostContourOpenings();
   sp().settings = { ...(sp().settings || {}), north_deg: 0, sun_rays: true };
   c.hass = { ...c.hass, states: { ...c.hass.states, 'sun.sun': {
     entity_id: 'sun.sun', state: 'above_horizon',
@@ -107,6 +136,7 @@ const res = await page.evaluate(async () => {
   sp().openings = [{
     id: 'wt1', type: 'door', x: 0.55, y: 0.25, angle: 90, length: 0.09, flip_v: false,
   }];
+  hostContourOpenings();
   await upd();
   out.doorDrawn = !!sr().querySelector('[data-hp="opening"][data-kind="door"]');
   const bodyD = shared[0]?.getAttribute('d') || sr().querySelector('[data-hp="wall"]')?.getAttribute('d') || '';
@@ -133,6 +163,7 @@ const res = await page.evaluate(async () => {
     { id: 'wtGateFlipped', type: 'gate', x: 0.55, y: 0.30, angle: 90, length: 0.08,
       flip_v: true },
   ];
+  hostContourOpenings();
   await upd();
   const sharedGateDefault = firstGateTurn('wtGateDefault');
   const sharedGateFlipped = firstGateTurn('wtGateFlipped');
@@ -158,6 +189,7 @@ const res = await page.evaluate(async () => {
   sp().openings = [{
     id: 'wt1', type: 'door', x: 0.55, y: 0.25, angle: 90, length: 0.09, flip_v: true,
   }];
+  hostContourOpenings();
   await upd();
 
   sp().settings = { ...(sp().settings || {}), hide_openings: true, show_borders: true };
diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index 062a8351..fc86432b 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -25,7 +25,9 @@
   An invalid open passage also retains its specific actionable error instead
   of being masked by the generic wall-model migration blocker. The compact
   space card keeps wall-hosted doors, windows, gates and passages visible after
-  the migration as well.
+  the migration as well. Wall-hosted windows keep casting sunlight after an
+  edit, partial open boundaries remain writable on migrated plans, and clearing
+  wall thickness no longer restores its previous value.
   Ambiguous legacy geometry is
   left unchanged with a recovery prompt. No Plan editor controls or
   zero-thickness-wall behaviour changed
diff --git a/docs/CHANGELOG.ru.md b/docs/CHANGELOG.ru.md
index 076877d7..b89673ae 100755
--- a/docs/CHANGELOG.ru.md
+++ b/docs/CHANGELOG.ru.md
@@ -30,6 +30,9 @@
   открытый проход по-прежнему получает своё точное сообщение об ошибке, а не
   общий блокер миграции стен. Компактная карточка пространства также не теряет
   после миграции двери, окна, ворота и проходы, привязанные к стенам.
+  Окна на стенах продолжают пропускать солнечные лучи после правки, частичные
+  открытые границы сохраняются и на уже мигрированных планах, а удалённая
+  толщина стены больше не восстанавливается в прежнее значение.
   Неоднозначная старая геометрия остаётся без изменений с подсказкой по
   восстановлению. Кнопки редактора плана и поведение стен нулевой толщины не
   менялись
diff --git a/src/houseplan-card.ts b/src/houseplan-card.ts
index ef32adaa..2e283587 100755
--- a/src/houseplan-card.ts
+++ b/src/houseplan-card.ts
@@ -7293,7 +7293,11 @@ class HouseplanCard extends LitElement {
     return this._t(`wall_model.reason.${reason}`);
   }
 
-  private _commitPhysicalGeometry(name: string, before: SpaceGeometryState | null): boolean {
+  private _commitPhysicalGeometry(
+    name: string,
+    before: SpaceGeometryState | null,
+    additionalAuthoredPoints: readonly (readonly number[])[] = [],
+  ): boolean {
     if (!before || !this._serverCfg) return false;
     const liveCandidate = this._serverCfg;
     const editedState = this._geometrySnapshotFromConfig(liveCandidate, before.spaceId);
@@ -7360,6 +7364,7 @@ class HouseplanCard extends LitElement {
       const authoredPoints = this._path.length >= 2
         ? this._path.map((point) => [point[0] / NORM_W, point[1] / NORM_W])
         : [];
+      authoredPoints.push(...additionalAuthoredPoints.map((point) => [point[0], point[1]]));
       safe = wallModelOffGridValueCount(afterSpace)
         <= wallModelOffGridValueCount(historyBefore, authoredPoints)
         && this._checkSpacePhysicalGeometry(committedCandidate, before.spaceId).ok;
@@ -11650,7 +11655,10 @@ class HouseplanCard extends LitElement {
       sp.openings = purgeOpeningsOnSpan(sp.openings, sg, NORM_W, this._gridPitch * 6);
       const removedOpenings = (sp.openings || []).length < beforeOp;
       this._persistOpenCuts(next);
-      if (this._commitPhysicalGeometry(this._t('history.open_boundary'), before)) {
+      if (this._commitPhysicalGeometry(this._t('history.open_boundary'), before, [
+        [sg[0] / NORM_W, sg[1] / NORM_W],
+        [sg[2] / NORM_W, sg[3] / NORM_W],
+      ])) {
         if (removedOpenings) this._showToast(this._t('toast.openwall_openings_removed'));
         this._showToast(this._t('toast.boundary_opened'));
       }
@@ -11994,6 +12002,15 @@ class HouseplanCard extends LitElement {
       next = setWallThickness(sp.walls, d.a, d.b, cm, this._wallKeyPitch, NORM_W);
     }
     next = this._normalizeWalls(next, openCuts);
+    // ADR 282 Stage 1: this writer knows that absence from `next` is an
+    // explicit zero chosen by the user, not a missing compatibility record.
+    // Mirror that intent into the canonical catalogue before the common
+    // barrier; otherwise its lineage fallback would resurrect the old cm.
+    for (const segment of sp.wall_segments || []) {
+      segment.cm = thicknessCmAt(
+        next, segment.a, segment.b, GRID_STEP_N, 1,
+      );
+    }
     if (next.length) sp.walls = next;
     else delete sp.walls;
     this._wallDialog = null;
@@ -15448,8 +15465,10 @@ class HouseplanCard extends LitElement {
         .map((r) => ({ id: r.id || '', poly: roomPoly(r) }))
         .filter((r): r is { id: string; poly: number[][] } => !!r.id && !!r.poly);
       const windows = this._openingsR
-        // An independent-wall window is not an exterior sun source (#132).
-        .filter((o) => o.type === 'window' && !o.host)
+        // A contour-wall host is stable identity metadata, not a different
+        // physical carrier. Only an independent partition window is excluded
+        // from exterior sunlight (#132, ADR 282 Stage 1).
+        .filter((o) => o.type === 'window' && o.host?.kind !== 'partition')
         .map((o) => ({ id: o.id, x: o.rx, y: o.ry, angle: o.angle, length: o.rlen }));
       const walls = this._spaceWalls;
       const openCuts = this._openPairs().flatMap((p) => p.segs);
diff --git a/test/wall-segment-model.test.mjs b/test/wall-segment-model.test.mjs
index 18379d92..7e6f5b90 100644
--- a/test/wall-segment-model.test.mjs
+++ b/test/wall-segment-model.test.mjs
@@ -84,6 +84,23 @@ test('v7 rectangle migrates atomically to the complete id catalogue and is idemp
   assert.deepEqual(second.config, first.config);
 });
 
+test('an explicit canonical zero is not resurrected from the old thickness projection', () => {
+  const base = commitWallSegmentModel(configOf({
+    id: 'floor', title: 'Floor', rooms: [rectangle('room')],
+    walls: [{
+      key: wallKey([0, 0], [1, 0], GRID_STEP_N),
+      a: [0, 0], b: [1, 0], cm: 20,
+    }],
+  })).config;
+  const edited = structuredClone(base);
+  const topId = edited.spaces[0].rooms[0].wall_ids[0];
+  edited.spaces[0].wall_segments.find((segment) => segment.id === topId).cm = 0;
+  delete edited.spaces[0].walls;
+  const result = commitWallSegmentModel(edited).config.spaces[0];
+  assert.equal(result.wall_segments.find((segment) => segment.id === topId).cm, 0);
+  assert.equal(result.walls, undefined);
+});
+
 test('partial shared side is atomised once and every atom has one or two owners', () => {
   const result = commitWallSegmentModel(configOf({
     id: 'floor', title: 'Floor',