dillon1000/react

RFC 6: Deprecate unsafe lifecycles (#12028)

* Added unsafe_* lifecycles and deprecation warnings
If the old lifecycle hooks (componentWillMount, componentWillUpdate, componentWillReceiveProps) are detected, these methods will be called and a deprecation warning will be logged. (In other words, we do not check for both the presence of the old and new lifecycles.) This commit is expected to fail tests.

* Ran lifecycle hook codemod over project
This should handle the bulk of the updates. I will manually update TypeScript and CoffeeScript tests with another commit.
The actual command run with this commit was: jscodeshift --parser=flow -t ../react-codemod/transforms/rename-unsafe-lifecycles.js ./packages/**/src/**/*.js

* Manually migrated CoffeeScript and TypeScript tests

* Added inline note to createReactClassIntegration-test
Explaining why lifecycles hooks have not been renamed in this test.

* Udated NativeMethodsMixin with new lifecycle hooks

* Added static getDerivedStateFromProps to ReactPartialRenderer
Also added a new set of tests focused on server side lifecycle hooks.

* Added getDerivedStateFromProps to shallow renderer
Also added warnings for several cases involving getDerivedStateFromProps() as well as the deprecated lifecycles.
Also added tests for the above.

* Dedupe and DEV-only deprecation warning in server renderer

* Renamed unsafe_* prefix to UNSAFE_* to be more noticeable

* Added getDerivedStateFromProps to ReactFiberClassComponent
Also updated class component and lifecyle tests to cover the added functionality.

* Warn about UNSAFE_componentWillRecieveProps misspelling

* Added tests to createReactClassIntegration for new lifecycles

* Added warning for stateless functional components with gDSFP

* Added createReactClass test for static gDSFP

* Moved lifecycle deprecation warnings behind (disabled) feature flag

Updated tests accordingly, by temporarily splitting tests that were specific to this feature-flag into their own, internal tests. This was the only way I knew of to interact with the feature flag without breaking our build/dist tests.

* Tidying up

* Tweaked warning message wording slightly
Replaced 'You may may have returned undefined.' with 'You may have returned undefined.'

* Replaced truthy partialState checks with != null

* Call getDerivedStateFromProps via .call(null) to prevent type access

* Move shallow-renderer didWarn* maps off the instance

* Only call getDerivedStateFromProps if props instance has changed

* Avoid creating new state object if not necessary

* Inject state as a param to callGetDerivedStateFromProps
This value will be either workInProgress.memoizedState (for updates) or instance.state (for initialization).

* Explicitly warn about uninitialized state before calling getDerivedStateFromProps.
And added some new tests for this change.

Also:
* Improved a couple of falsy null/undefined checks to more explicitly check for null or undefined.
* Made some small tweaks to ReactFiberClassComponent WRT when and how it reads instance.state and sets to null.

* Improved wording for deprecation lifecycle warnings

* Fix state-regression for module-pattern components
Also add support for new static getDerivedStateFromProps method