Addresses PR review: the containing block for an absolutely-positioned child
is the **padding box** (inside the borders), not the "border-box". Verified by
running yoga (an abs child at top:0/left:0 insets by the border only, never by
padding — confirmed across border/padding combos) and the real Ink/vue-tui
renderers (X lands at the inner-border edge, byte-identical in both).
- Tighten the regression test: exact-frame assertions instead of `toContain`,
including a border+padding case that distinguishes the padding box from the
content box — the assertion that would have caught the original wording slip
(presence-only assertions could not).
- Correct "containing block (border-box)" -> "padding box (inside the borders)"
in paint.ts, layout-guards.ts, and ink-divergences.md. (The unrelated
"border-box-like" *sizing* notes are correct and left as-is.)
No runtime behavior change; the code already used yoga's computed position.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The zero-content-area guard (layout-guards + paint.ts) suppressed ALL
children of a Box whose inner content rect collapsed to zero, including
position:"absolute" children. An absolutely-positioned child is placed
against the containing block (border-box), not the content rect, so Ink
v7.0.4 paints it (verified by running real Ink: a w=2 h=2 single-border
box with an absolute child renders "┌┐#\n└X"); vue-tui dropped it,
rendering "┌┐#\n└┘".
- layout-guards: exempt POSITION_TYPE_ABSOLUTE children from the hide loop
so they keep their layout.
- paint: move overflow-clip setup above the zero-content early-return and,
in that branch, paint only absolute children (still clipped by
overflow:hidden, matching Ink) while keeping in-flow children suppressed
(the blessed degenerate-box divergence).
Flow-child suppression and overflow:hidden clipping both stay Ink-aligned
(verified byte-identical against real Ink). Known limitation: an absolute
descendant nested under a suppressed in-flow child is still dropped (the
flow ancestor is removed from layout) — scoped to direct absolute children.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Yunfei He