[v2] Tabs fail to render when they have only one child

[aeneasr]

🐛 Bug Report

(A clear and concise description of what the bug is)

Have you read the Contributing Guidelines on issues?

yes

To Reproduce

In a mdx file, write:

import Tabs from '@theme/Tabs'
import TabItem from '@theme/TabItem'

<Tabs
  defaultValue="node"
  values={[
    {label: 'NodeJS', value: 'node'},
  ]}>
  <TabItem value="node">
    asdf
  </TabItem>
</Tabs>

Expected behavior

This will fail to render with index.js?3e4b:6 Uncaught (in promise) TypeError: children.map is not a function caused by 8c9f948 and more specifically the removal of 8c9f948#diff-5548122e1da708235c90f8d8cc552ffa69c199f1dd82ca505c9577ac7255da73L114

Adding a non-sense tab like so will fix this:

import Tabs from '@theme/Tabs'
import TabItem from '@theme/TabItem'

<Tabs
  defaultValue="node"
  values={[
    {label: 'NodeJS', value: 'node'},
  ]}>
  <TabItem value="node">
    asdf
  </TabItem>
  <TabItem value="placeholder" />
</Tabs>

Actual Behavior

Rendering should not fail

Your Environment

• Docusaurus version used: alpha 69

Reproducible Demo

(Paste the link to an example repo, including a siteConfig.js, and exact instructions to reproduce the issue.)

[doucol]

I'm seeing evidence that this has resurfaced with the 2.3 release. We had one page with a single tab in the tabset and it was causing the TypeError: children.map is not a function error. Removed the tabset and error disappears.

[Josh-Cena]

Let's track the new error in #8591