[css-flexbox-1] Decision to make definiteness of flex items' main size depend on flex-basis's definiteness

Hi all,

I've been looking through a few non-interoperable parts of flexbox again
recently, and have run into
<https://codepen.io/gsnedders/pen/WRZQrx?editors=1100#0> again. Notably,
Edge and Firefox both pass this test case, and Chrome and Safari fail.
Except, as it turns out, the behaviour in Chrome and Safari is right.
(Actually, the behaviour in Safari is wrong, it just happens to be right
for that test case, but let's never mind details!)

I can't work out is where the behaviour in Edge and Firefox comes from,
though maybe it is down to interpretation of the spec prior to
<https://github.com/w3c/csswg-drafts/commit/2f0ad00527a726c92a6567b210696142e8c2b722>
and whether you need to measure content in this case? Though that
doesn't seem true? I haven't dug too deep into this though!

That said, what I'm really here to ask is when and why we decided to go
with the behaviour the spec and Chrome now have and hence against the
Edge/Firefox behaviour. This seems to be something that trips web
authors up a fair bit (there's *lots* of bugs in the Chromium bug
tracker about this!). Something to point people at as to, "hey, here's
why the spec does this nowadays, and why we think this is better
behaviour", ideally—though obviously a blog post summarising it may well
be needed!

/gsnedders

Received on Thursday, 26 January 2017 05:32:46 UTC