1462514 - Block breaking is inconsistent when padding is applied on different level

Status: RESOLVED DUPLICATE of bug 1677917

(Core :: Layout: Block and Inline, enhancement, P3)

Description

[Xidorn Quan [:xidorn] UTC+10]

Attachment: testcase

See the testcase.

The only difference between the two boxes are that, one applies padding on an outer element, the other applies it on the same element containing the text. They should have identical reflow result, but they don't.

The reason seems to be that when we reflow lines, we set the mBEndEdge to available bsize - padding bend[1], while we are probably doing something different for reflowing block, so that when a line itself can be placed within the remaining space, but cannot when taking padding into consider, it would produce different results in the two cases.

This issue is found when looking at the testcase of bug 368020, which starts failing when the line height gets changed slightly in bug 1458159.


[1] https://searchfox.org/mozilla-central/rev/da499aac682d0bbda5829327b60a865cbc491611/layout/generic/BlockReflowInput.cpp#127