STR: 0. Set pref devtools.flexboxinspector.enabled to true 1. Visit this data URL: data:text/html,<div style="display:flex;writing-mode:vertical-rl"><span>abc 2. Right-click "abc" and choose "inspect" 3. Click the "flex" badge in the DOM view. 4. In the "Layout" inspector pane (to the right), click "1. span" to expand the flex-item info for the <span>. ACTUAL RESULTS: The pane reports "Content width", "Min-width", "Max-width", and "Final width", but the main axis is the vertical axis. EXPECTED RESULTS: The pane should report "height" values.

In particular: IF the flex container's computed "writing-mode" == "horizontal-tb": * flex-direction:row/row-reverse means horizontal (widths), vs. column/column-reverse means vertical (heights) ELSE: * It's the opposite. i.e.: * flex-direction:row/row-reverse means vertical (heights), vs. column/column-reverse means horizontal (widths)

This will change a bit with bug 1495717 as we don't display these properties as is anymore. But the bug still exists. Let's wait for that bug to land, and then investigate again. At that time, it will make more sense to use this test case instead: data:text/html,<div style="display:flex;writing-mode:vertical-rl"><span style="min-width:300px;min-height:200px">abc

Let's wait for bug 1497589 to land since that'll give us the physical direction of the main and cross axis. I think we should expose them on the FlexboxActor's form object because they will be useful in many cases.

Try results: https://treeherder.mozilla.org/#/jobs?repo=try&revision=128989b13e69b3a54d2f6f258c291f3cccbae243

Pushed by mtigley@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/f2d6d537d09e Devtools flexbox inspector incorrectly reports width values for row-oriented vertical-writing-mode flexbox. r=gl

Backed out changeset f2d6d537d09e (Bug 1488885) for dt failures in devtools/client/inspector/flexbox/test/browser_flexbox_sizing_info_for_different_writing_modes.js CLOSED TREE Push with failures: https://treeherder.mozilla.org/#/jobs?repo=mozilla-inbound&resultStatus=testfailed%2Cbusted%2Cexception%2Cusercancel%2Crunnable&fromchange=712cf5b07342648b8a9216c2cfadf7c794a5dac3&selectedJob=209162886 Failure log: https://treeherder.mozilla.org/logviewer.html#?job_id=209167602&repo=autoland&lineNumber=1806 Backout push: https://treeherder.mozilla.org/#/jobs?repo=autoland&resultStatus=pending%2Crunning%2Ctestfailed%2Cbusted%2Cexception%2Cusercancel%2Crunnable&searchStr=linux%2Copt%2Cmochitests%2Cwith%2Ce10s%2Ctest-linux32%2Fopt-mochitest-devtools-chrome-e10s-1%2Cm-e10s%28dt1%29&revision=cc154f685edec9f190a9d3b0c8acd551861879b4

Micah, for info the assert that failed here just landed so that's why your try pushes didn't show it. In your test you have a call to `ok()` which is incorrect: ok(minDimension.textContent, expectedDimension, "The flex item sizing has the correct dimension value."); You want to use `is()` here, otherwise you are only checking that `minDimension.textContent` is not false.

My apologies. I missed the incorrect call to "ok()" before pushing. Thank you for letting me know. I will get it fixed up!

Pushed by mtigley@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/afbdda6211c9 Devtools flexbox inspector incorrectly reports width values for row-oriented vertical-writing-mode flexbox. r=gl