Bugzilla

This bug is similar to bug 1743890. We are currently unable to push a monolithic flex item to the next page if the flex container is running out of available block-size. Therefore, the last unable-to-fit flex item in current page contributes to the flex container's block-size, which makes the entire flex container's block-size exceeds the available block-size. In these testcases, the line containing the flex container is not the first line in a block frame (the first line is "Does the following content start on this same page?"), `nsBlockReflowContext::PlaceBlock()` [1] will return `false` to stop the reflow, and the block frame will push the line containing flex container to the next-in-flow [2].

[1] https://searchfox.org/mozilla-central/rev/3c194fa1d6f339036d2ec9516bd310c6ad612859/layout/generic/nsBlockReflowContext.cpp#413-422
[2] https://searchfox.org/mozilla-central/rev/3c194fa1d6f339036d2ec9516bd310c6ad612859/layout/generic/nsBlockFrame.cpp#4326-4328

This bug is similar to bug 1743890. We are currently unable to push a monolithic flex item to the next page if the flex container is running out of available block-size. (We treat a line of text as monolithic.) Therefore, the last unable-to-fit flex item in current page contributes to the flex container's block-size, which makes the entire flex container's block-size exceeds the available block-size. In these testcases, the line containing the flex container is not the first line in a block frame (the first line is "Does the following content start on this same page?"), `nsBlockReflowContext::PlaceBlock()` [1] will return `false` to stop the reflow, and the block frame will push the line containing flex container to the next-in-flow [2].

[1] https://searchfox.org/mozilla-central/rev/3c194fa1d6f339036d2ec9516bd310c6ad612859/layout/generic/nsBlockReflowContext.cpp#413-422
[2] https://searchfox.org/mozilla-central/rev/3c194fa1d6f339036d2ec9516bd310c6ad612859/layout/generic/nsBlockFrame.cpp#4326-4328