False positive getDefaultProps warning when mixing development and production versions

[mondwan]

As migrating from 15.4 to 15.5, I am rewrite original react components with create-react-class.

However, there is a warning.

react-15.5.4.js?bust=1497843639843:3287 Warning: getDefaultProps is only used on classic React.createClass definitions. Use a static property named `defaultProps` instead.

As I am really transferring from a classic React.createClass definition, I would like to ask is this warning appropriate? Or, this is a depreciation sames as the level of migrating to create-react-class?

Ooops, I get ticket #9999 :D

[aweary]

@mondwan can you share an example reproducing the issue? I'm not seeing the warning when using the latest create-react-class version, or the last 15.5 release. Example. You can use this JSFiddle as a starting point for reproducing.

[mondwan]

https://jsfiddle.net/84v837e9/105/

For non minified version, it works as expected. However, it does not if using minified version

Maybe related to issue #9689?

[aweary]

@mondwan the issue is that you're using the minified create-react-class build, but the unminified react build. This means that the internal flag that create-react-class uses to suppress this warning is not applied, so React warns.

Make sure you use the correct build for your environment (minified for production, unminified for development).

[mondwan]

Umm, but why this is a warning at the first place? 2017年6月20日 18:03，"Brandon Dail" <notifications@github.com>寫道：

…

Closed #9999 <#9999>. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#9999 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ADuAo2St_74neexrI9m8B4o0p6WQ3uXhks5sF5jkgaJpZM4N9x7V> .

[aweary]

Because getDefaultProps is only used for components created with createReactClass. For example, the warning will catch cases where someone is moving from createClass to ES6 classes and they forget to remove getDefaultProps in favor of defaultProps.

You'll never get the warning when using the correct build of create-react-class. It's also important to use minified bundles for react and react-dom in production, as they're much more performant. On the same token, it's useful to use the unminified build in development as it contains a sizeable set of useful checks and warnings.

[mondwan]

That's the point. I am still using react.createClass instead of es6 class even though this has been replaced by create-react-class. It should not get a warning at the first place. Or, create-react-class is made of es6 class. So, rules like that are effective? 2017年6月20日 18:32，"Brandon Dail" <notifications@github.com>寫道：

…

Because getDefaultProps is only used for components created with createReactClass. For example, the warning will catch cases where someone is moving from createClass to ES6 classes and they forget to remove getDefaultProps in favor of defaultProps. You'll never get the warning when using the correct build of create-react-class. It's also important to use minified bundles for react and react-dom in production, as they're much more performant. On the same token, it's useful to use the unminified build in development as it contains a sizeable set of useful checks and warnings. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#9999 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ADuAow64dLOLEjrIDwGn5DOSqeebBpttks5sF5-lgaJpZM4N9x7V> .

[aweary]

You're getting the warning because you're using the production create-react-class build with the development react build. The production build strips out the code that prevents this warning in development

[gaearon]

In general we don't support mixing production and development versions of libraries.

[gaearon]

It would still be nice if there was a way to avoid the false positive as this is pretty confusing. Maybe we can turn a flag into a number, and always set it in DEV. If it's not set then we're in PROD mode and shouldn't check.

[mondwan]

Ahhh. I see your points. Thanks for the explanations. Actually, it always show warnings about this problem. However, it is hided by development codes and those codes get striped when running in production. In order to get rid of the warnings, I better changes those calls to defaultProps. Am I correct? 2017年6月21日 下午3:52，"Brandon Dail" <notifications@github.com>寫道：

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You're getting the warning because you're using the production create-react-class build with the development react build. The production build strips out the code that prevents this warning in development — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#9999 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ADuAo5JvSA_WtxTh_YlhpNCQOTZqDLOlks5sGMvXgaJpZM4N9x7V> .

[gaearon]

No, to fix the false positive warnings, you need to either use:

• react.js and create-react-class.js (development)
• react.min.js and create-react-class.min.js (production)

The mistaken warning occur when you mix development and production versions of these two libraries.

[mondwan]

But it shows no warnings after changing to defaultProps as it suggested. 2017年6月21日 下午6:21，"Dan Abramov" <notifications@github.com>寫道：

…

No, to fix the false positive warnings, you need to either use: - react.js and create-react-class.js (development) - react.min.js and create-react-class.min.js (production) The mistaken warning occur when you mix development and production versions of these two libraries. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#9999 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ADuAo0l2pw-Cielxxz32lpFlMcvgjIfUks5sGO62gaJpZM4N9x7V> .