[gaojunran]

An absolutely-positioned box with height: auto was capped by the space left in its containing block, so content taller than that space got squeezed. A column flex container inside such a box would fall back to its min-content main size and shrink items that declared an explicit height.

Root cause: compute_special_position filled both axes of the max_content constraint with containing block size - insets. Shrink-to-fit is inline-axis only (CSS2.1 §10.3.7); the block axis of an auto-height abs-pos box is content-determined (§10.6.4). With bottom: 200px inside a 0-height bar the value went negative, got floored to 0, and flex_box then took the
available < max-content branch (min-content floor) for the column container.

Fix: keep the inline-axis constraint (behaviour unchanged, still clamped by the element's own min/max), pass None for the block axis, chosen by writing_mode. None is already a supported "indefinite" state for every consumer — flow containers measure content when the cross size is indefinite, and flex takes max_content_size when available space is None.

[TtTRz]

Unconditionally clearing the block-axis max_content also removes the explicit max-height constraint needed to calculate the intrinsic width of a wrapping column flex container.

Inside a 200px × 200px positioned containing block, use:

.container {
  position: absolute;
  top: 0;
  left: 0;
  display: flex;
  flex-direction: column;
  flex-wrap: wrap;
  max-height: 100px;
}

.item {
  width: 50px;
  height: 60px;
  flex: none;
}

With three items, the parent commit and Chrome produce a container width of 150px. This commit produces 50px, while the items still occupy three columns and overflow the container.

The initial AllSize pass measures a single column without the height constraint. The subsequent Position pass wraps the items, but the incorrect width is already fixed. Flexbox §9.9.2 requires the max-content cross size of a multiline column container to account for the resulting column widths.

Suggested fix

Remove the containing block’s remaining-space fallback from the block axis, while preserving definite sizes and resolved explicit maxima:

let max_content = min_max_limit.normalized_size(match style.writing_mode() {
    WritingMode::HorizontalTb => OptionSize::new(
        inline_max_content.width,
        size.height.or(min_max_limit.max_height),
    ),
    WritingMode::VerticalLr | WritingMode::VerticalRl => OptionSize::new(
        size.width.or(min_max_limit.max_width),
        inline_max_content.height,
    ),
});

[TtTRz]

LGTM