react-is@16.12.0 changed the behavior of isMemo function, which cause enzyme selector fail.

[changran52m]

Current behavior

https://codesandbox.io/s/gracious-sun-qih2n broken
https://codesandbox.io/s/agitated-firefly-ows1l working

Expected behavior

console.log("Icon is icon?:", mount().is(EditIcon)); // true

Your environment

React + Enzyme

Root cause

Please check in detail here facebook/react#17278

Proposal:

1. fix the is function call to isMemo to take component.type instead of component itself.
2. pin the dependency of react-is to 16.11.0

API

• shallow
• mount
• render

Version

library	version
enzyme	3.10.0
react	16.12.0
react-dom
react-test-renderer
adapter (below)	15.1

Adapter

• enzyme-adapter-react-16
• enzyme-adapter-react-16.3
• enzyme-adapter-react-16.2
• enzyme-adapter-react-16.1
• enzyme-adapter-react-15
• enzyme-adapter-react-15.4
• enzyme-adapter-react-14
• enzyme-adapter-react-13
• enzyme-adapter-react-helper
• others ( )

Related issue facebook/react#17457
Related issue facebook/react#17278

[ljharb]

Yes, this is blocking #2292.

If you think you have a fix that's not pinning to 16.11, please link me to a branch and I'll pull in the commit :-)

[lh0x00]

If you think you have a fix that's not pinning to 16.11, please link me to a branch and I'll pull in the commit :-)

I created #2298 , please review it :) .

[ljharb]

Thanks; i was hoping for a branch instead of a second PR, but I’ll take a look.

[lh0x00]

I closed PR #2298 and created #2300 . Please check it again.

[ljharb]

Fixed in #2300.