PropTypes throwing errors in production?

[prettymuchbryce]

Currently in React 15.5.0, PropTypes called manually can result in an Error being thrown in production. This is due to the productionTypeChecker now being used in 15.5.0. We suspect that the boolean argument passed to invariant was either intended to be flipped, or warning was intended to be used instead here. Passing false to invariant will always throw an error.

We're currently seeing this occur in production as a result of using react-router v1.0.3, which expects PropType validators to return errors, and doesn't account for any errors being thrown.

[franjohn21]

Codepen: http://codepen.io/franjohn21/pen/Wjeemd

[Daniel15]

This seems to be an intentional design choice. From the readme in this repo:

In production, all validator functions are replaced with empty functions that throw an error. This is done to optimize the bundle size.

I suspect the reasoning is that proptype checks are usually only done in development. However, I wonder why it doesn't just become a no-op in production, rather than throwing 😕

[franjohn21]

If I'm reading the docs correctly, this functionality should throw an error in a future major release.

In a future major release of React, the code that implements PropType validation functions will be stripped in production. Once this happens, any code that calls these functions manually (that isn't stripped in production) will throw an error.

So throwing an error now is unintentional and breaks production builds particularly where 3rd party libraries manually called proptype functions.

[aweary]

Maybe @acdlite or @gaearon can shed some light on why prop-types is throwing in production before the next major React release.

[gaearon]

This was an intentional breaking change inprop-types itself (as it is a completely new package) but I didn’t fully realize we switched React 15.5 to actually use the prop-types (and thus trigger the error).

We need to put out a fix for this asap, thanks for reporting.

[gaearon]

This is fixed in prop-types@15.5.7 and we'll update React 15.x to enforce depending on it soon.
In the meantime you should be able to run rm -rf node_modules and npm install to fix this.

[gaearon]

Fixed in react@15.5.4.

[gaearon]

In case anyone is confused, the intended behavior is explained here:

https://github.com/reactjs/prop-types/blob/master/README.md#difference-from-reactproptypes-dont-call-validator-functions

I verified that react@15.5.4 restores the old behavior for React.PropTypes, fixing the react-router@1.x problem.

[bvaughn]

react@15.5.4 ^

[gaearon]

Thanks 😄 I keep typing that for some reason