CSS flex-basis not working when flex-direction is 'column'

Question

My goal is to create a two-column layout with flexbox wherein the first column has two rows and the second column has one, like this:

Setting flex-basis: 100% on the third item gives the desired effect, but only when the container's flex-direction is row:

Changing flex-direction to column results in the following, unless the height is set explicitly, which is infeasible in my project:

How can I get the first image without explicitly setting the height of the container?

Here's a Plunker illustrating the problem.

body {
  display: flex;
  height: 100px;
  width: 100px;
}
.container {
  display: flex;
  flex-direction: column; /* Setting this to `row` gives the expected effect,but rotated */
  flex-grow: 1;
  flex-wrap: wrap;
  /* height: 100%; */ /* Setting this fixes the problem, but is infeasible for my project*/
}
.item {
  flex-grow: 1;
}
.one {
  background-color: red;
}
.two {
  background-color: blue;
}
.three {
  background-color: green;
  flex-basis: 100%;
}

<div class="container">
  <div class="item one">&nbsp;</div>
  <div class="item two">&nbsp;</div>
  <div class="item three">&nbsp;</div>
</div>

Answer 1

Why it doesn't work:

Flex wrap only happens when the initial main size of the flex items overflows the flex container. In the case of flex-direction: row, this is when they flex items are wider than the container. With flex-direction: column, they must overflow the height of the container.

But in CSS, height behaves fundamentally differently than width. The height of a container in CSS is determined by the height of its children. Thus, without something constraining the container’s height, they flex items will never overflow; they just make their container taller. If they don’t overflow, they won’t wrap.

Possible solutions:

You have to constrain the height of the container. The obvious way (which you said is off the table), is setting an explicit height or max-height.

Ask yourself why you need to constrain the height. Is it to stay within the viewport? You could use viewport-relative units and set something like max-height: 100vh. Is it to equal the height of another column outside this flex container? You might be able to constrain it with another flexbox. Make this flex container a flex item in an outer flexbox. Something else in that outer flexbox would have to establish its height, though.