apps/web/e2e/a11y.spec.ts

@@ -141,20 +141,36 @@ async function expectNoHorizontalScroll(page: Page, label: string): Promise<void
       }
     }
 
-    // Raw: every box reaching past the viewport, no filtering at all.
-    const past: string[] = [];
-    for (const el of Array.from(document.querySelectorAll('body *'))) {
-      const rect = el.getBoundingClientRect();
-      if (rect.width > 0 && rect.right > limit + 1) {
-        past.push(`${describe(el)} right=${Math.round(rect.right)} w=${Math.round(rect.width)}`);
+    /** Content inside a scroll container may exceed the viewport — that is
+     *  the remedy. But only when the CONTAINER fits: a scroller that is
+     *  itself too wide still pushes the page. */
+    const insideFittingScroller = (el: Element): boolean => {
+      for (let node = el.parentElement; node && node !== doc; node = node.parentElement) {
+        const ox = getComputedStyle(node).overflowX;
+        if (ox === 'auto' || ox === 'scroll' || ox === 'hidden') {
+          return node.getBoundingClientRect().right <= limit + 1;
+        }
       }
-    }
+      return false;
+    };
+
+    // Widest reach first, so a long tail of clipped children cannot bury the
+    // one box that actually pushes the page.
+    const past = Array.from(document.querySelectorAll('body *'))
+      .map((el) => ({ el, rect: el.getBoundingClientRect() }))
+      .filter(({ rect }) => rect.width > 0 && rect.right > limit + 1)
+      .sort((a, b) => b.rect.right - a.rect.right)
+      .map(
+        ({ el, rect }) =>
+          `${describe(el)} right=${Math.round(rect.right)} w=${Math.round(rect.width)}` +
+          `${insideFittingScroller(el) ? ' [in fitting scroller]' : ' <-- pushes page'}`,
+      );
 
     return {
       overflowBy: doc.scrollWidth - limit,
       viewport: `html client=${limit} scroll=${doc.scrollWidth} | body client=${document.body.clientWidth} scroll=${document.body.scrollWidth} rect=${Math.round(document.body.getBoundingClientRect().width)}`,
       overflowing: overflowing.slice(0, 15),
-      past: past.slice(0, 15),
+      past: past.slice(0, 40),
     };
   });
   const diagnosis = [