Large child of overflow: hidden parent causes an unexpected page break.

[BadCoder1337]

I tried to create some "pyramid" document (desired layout, source, demo) with different paper formats but got some weird PDF results in Chrome and WeasyPrint.

With @liZe help we found a minimal example showing the issue

<div style="overflow: hidden; height: 10cm; border: 1px solid red">
  <div>abc</div>
  <div style="height: 100cm">def</div>
</div>

and the workaround

img {
  display: block;
  margin-top: -100cm;
  transform: translate(0, 100cm);
}

Version Info:
Chrome 114.0.5735.199
WeasyPrint 59.0

[liZe]

Thanks for the bug report.

Here’s the related paragraph in the specification:

In addition to any content which is not generally fragmentable, UAs may consider as monolithic any elements with overflow set to auto or scroll and any elements with overflow: hidden and a non-auto logical height (and no specified maximum logical height).

With "normal" words: we should not break boxes with defined height and hidden overflow.