Add an explicit Bridge protocol version to the frontend and backend components as well as a check during initialization to ensure that both are compatible. If not, the frontend will display either upgrade or downgrade instructions.
Note that only the `react-devtools-core` (React Native) and `react-devtools-inline` (Code Sandbox) packages implement this check. Browser extensions inject their own backend and so the check is unnecessary. (Arguably the `react-devtools-inline` check is also unlikely to be necessary _but_ has been added as an extra guard for use cases such as Replay.io.)
* Restore inspect-element bridge optimizations
When the new Suspense cache was integrated (so that startTransition could be used) I removed a couple of optimizations between the backend and frontend that reduced bridge traffic when e.g. dehydrated paths were inspected for elements that had not rendered since previously inspected. This commit re-adds those optimizations as well as an additional test with a bug fix that I noticed while reading the backend code.
There are two remaining TODO items as of this commit:
- Make inspected element edits and deletes also use transition API
- Don't over-eagerly refresh the cache in our ping-for-updates handler
I will addres both in subsequent commits.
* Poll for update only refreshes cache when there's an update
* Added inline comment
DevTools was built with a fork of an early idea for how Suspense cache might work. This idea is incompatible with newer APIs like `useTransition` which unfortunately prevented me from making certain UX improvements. This PR swaps out the primary usage of this cache (there are a few) in favor of the newer `unstable_getCacheForType` and `unstable_useCacheRefresh` APIs. We can go back and update the others in follow up PRs.
### Messaging changes
I've refactored the way the frontend loads component props/state/etc to hopefully make it better match the Suspense+cache model. Doing this gave up some of the small optimizations I'd added but hopefully the actual performance impact of that is minor and the overall ergonomic improvements of working with the cache API make this worth it.
The backend no longer remembers inspected paths. Instead, the frontend sends them every time and the backend sends a response with those paths. I've also added a new "force" parameter that the frontend can use to tell the backend to send a response even if the component hasn't rendered since the last time it asked. (This is used to get data for newly inspected paths.)
_Initial inspection..._
```
front | | back
| -- "inspect" (id:1, paths:[], force:true) ---------> |
| <------------------------ "inspected" (full-data) -- |
```
_1 second passes with no updates..._
```
| -- "inspect" (id:1, paths:[], force:false) --------> |
| <------------------------ "inspected" (no-change) -- |
```
_User clicks to expand a path, aka hydrate..._
```
| -- "inspect" (id:1, paths:['foo'], force:true) ----> |
| <------------------------ "inspected" (full-data) -- |
```
_1 second passes during which there is an update..._
```
| -- "inspect" (id:1, paths:['foo'], force:false) ---> |
| <----------------- "inspectedElement" (full-data) -- |
```
### Clear errors/warnings transition
Previously this meant there would be a delay after clicking the "clear" button. The UX after this change is much improved.
### Hydrating paths transition
I also added a transition to hydration (expanding "dehyrated" paths).
### Better error boundaries
I also added a lower-level error boundary in case the new suspense operation ever failed. It provides a better "retry" mechanism (select a new element) so DevTools doesn't become entirely useful. Here I'm intentionally causing an error every time I select an element.
### Improved snapshot tests
I also migrated several of the existing snapshot tests to use inline snapshots and added a new serializer for dehydrated props. Inline snapshots are easier to verify and maintain and the new serializer means dehydrated props will be formatted in a way that makes sense rather than being empty (in external snapshots) or super verbose (default inline snapshot format).
* Improve DevTools editing interface
This commit adds the ability to rename or delete keys in the props/state/hooks/context editor and adds tests to cover this functionality. DevTools will degrade gracefully for older versions of React that do not inject the new reconciler rename* or delete* methods.
Specifically, this commit includes the following changes:
* Adds unit tests (for modern and legacy renderers) to cover overriding props, renaming keys, and deleting keys.
* Refactor backend override methods to reduce redundant Bridge/Agent listeners and methods.
* Inject new (DEV-only) methods from reconciler into DevTools to rename and delete paths.
* Refactor 'inspected element' UI components to improve readability.
* Improve auto-size input to better mimic Chrome's Style editor panel. (See this Code Sandbox for a proof of concept.)
It also contains the following code cleanup:
* Additional unit tests have been added for modifying values as well as renaming or deleting paths.
* Four new DEV-only methods have been added to the reconciler to be injected into the DevTools hook: overrideHookStateDeletePath, overrideHookStateRenamePath, overridePropsDeletePath, and overridePropsRenamePath. (DevTools will degrade gracefully for older renderers without these methods.)
* I also took this as an opportunity to refactor some of the existing code in a few places:
* Rather than the backend implementing separate methods for editing props, state, hooks, and context– there are now three methods: deletePath, renamePath, and overrideValueAtPath that accept a type argument to differentiate between props, state, context, or hooks.
* The various UI components for the DevTools frontend have been refactored to remove some unnecessary repetition.
This commit also adds temporary support for override* commands with mismatched backend/frontend versions:
* Add message forwarding for older backend methods (overrideContext, overrideHookState, overrideProps, and overrideState) to the new overrideValueAtPath method. This was done in both the frontend Bridge (for newer frontends passing messages to older embedded backends) and in the backend Agent (for older frontends passing messages to newer backends). We do this because React Native embeds the React DevTools backend, but cannot control which version of the frontend users use.
* Additional unit tests have been added as well to cover the older frontend to newer backend case. Our DevTools test infra does not make it easy to write tests for the other way around.
This commit adds a new tab to the Settings modal: Debugging
This new tab has the append component stacks feature and a new one: break on warn
This new feature adds a debugger statement into the console override
DevTools previously used the NPM events package for dispatching events. This package has an unfortunate flaw though- if a listener throws during event dispatch, no subsequent listeners are called. I've replaced that event dispatcher with my own implementation that ensures all listeners are called before it re-throws an error.
This commit replaces that event emitter with a custom implementation that calls all listeners before re-throwing an error.
* Added rudimentary context menu hook and menu UI
* Added backend support for copying a value at a specific path for the inspected element
* Added backend support for storing a value (at a specified path) as a global variable
* Added special casing to enable copying undefined/unserializable values to the clipboard
* Added copy and store-as-global context menu options to selected element props panel
* Store global variables separately, with auto-incremented name (like browsers do)
* Added tests for new copy and store-as-global backend functions
* Fixed some ownerDocument/contentWindow edge cases
* Refactored context menu to support dynamic options
Used this mechanism to add a conditional menu option for inspecting the current value (if it's a function)
* Renamed "safeSerialize" to "serializeToString" and added inline comment
