Added an explicit type to all $FlowFixMe suppressions to reduce
over-suppressions of new errors that might be caused on the same lines.
Also removes suppressions that aren't used (e.g. in a `@noflow` file as
they're purely misleading)
Test Plan:
yarn flow-ci
## Hoistables
In the original implementation of Float, all hoisted elements were
treated like Resources. They had deduplication semantics and hydrated
based on a key. This made certain kinds of hoists very challenging such
as sequences of meta tags for `og:image:...` metadata. The reason is
each tag along is not dedupable based on only it's intrinsic properties.
two identical tags may need to be included and hoisted together with
preceding meta tags that describe a semantic object with a linear set of
html nodes.
It was clear that the concept of Browser Resources (stylesheets /
scripts / preloads) did not extend universally to all hositable tags
(title, meta, other links, etc...)
Additionally while Resources benefit from deduping they suffer an
inability to update because while we may have multiple rendered elements
that refer to a single Resource it isn't unambiguous which element owns
the props on the underlying resource. We could try merging props, but
that is still really hard to reason about for authors. Instead we
restrict Resource semantics to freezing the props at the time the
Resource is first constructed and warn if you attempt to render the same
Resource with different props via another rendered element or by
updating an existing element for that Resource.
This lack of updating restriction is however way more extreme than
necessary for instances that get hoisted but otherwise do not dedupe;
where there is a well defined DOM instance for each rendered element. We
should be able to update props on these instances.
Hoistable is a generalization of what Float tries to model for hoisting.
Instead of assuming every hoistable element is a Resource we now have
two distinct categories, hoistable elements and hoistable resources. As
one might guess the former has semantics that match regular Host
Components except the placement of the node is usually in the <head>.
The latter continues to behave how the original implementation of
HostResource behaved with the first iteration of Float
### Hoistable Element
On the server hoistable elements render just like regular tags except
the output is stored in special queues that can be emitted in the stream
earlier than they otherwise would be if rendered in place. This also
allow for instance the ability to render a hoistable before even
rendering the <html> tag because the queues for hoistable elements won't
flush until after we have flushed the preamble (`<DOCTYPE
html><html><head>`).
On the client, hoistable elements largely operate like HostComponents.
The most notable difference is in the hydration strategy. If we are
hydrating and encounter a hoistable element we will look for all tags in
the document that could potentially be a match and we check whether the
attributes match the props for this particular instance. We also do this
in the commit phase rather than the render phase. The reason hydration
can be done for HostComponents in render is the instance will be removed
from the document if hydration fails so mutating it in render is safe.
For hoistables the nodes are not in a hydration boundary (Root or
SuspenseBoundary at time of writing) and thus if hydration fails and we
may have an instance marked as bound to some Fiber when that Fiber never
commits. Moving the hydration matching to commit ensures we will always
succeed in pairing the hoisted DOM instance with a Fiber that has
committed.
### Hoistable Resource
On the server and client the semantics of Resources are largely the same
they just don't apply to title, meta, and most link tags anymore.
Resources hoist and dedupe via an `href` key and are ref counted. In a
future update we will add a garbage collector so we can clean up
Resources that no longer have any references
## `<style>` support
In earlier implementations there was no support for <style> tags. This
PR adds support for treating `<style href="..."
precedence="...">...</style>` as a Resource analagous to `<link
rel="stylesheet" href="..." precedence="..." />`
It may seem odd at first to require an href to get Resource semantics
for a style tag. The rationale is that these are for inlining of actual
external stylesheets as an optimization and for URI like scoping of
inline styles for css-in-js libraries. The href indicates that the key
space for `<style>` and `<link rel="stylesheet" />` Resources is shared.
and the precedence is there to allow for interleaving of both kinds of
Style resources. This is an advanced feature that we do not expect most
app developers to use directly but will be quite handy for various
styling libraries and for folks who want to inline as much as possible
once Fizz supports this feature.
## refactor notes
* HostResource Fiber type is renamed HostHoistable to reflect the
generalization of the concept
* The Resource object representation is modified to reduce hidden class
checks and to use less memory overall
* The thing that distinguishes a resource from an element is whether the
Fiber has a memoizedState. If it does, it will use resource semantics,
otherwise element semantics
* The time complexity of matching hositable elements for hydration
should be improved
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## Summary
This PR:
- Replaces the existing usages of methods from the `semver` library in
the React DevTools source with an inlined version based on
https://www.npmjs.com/package/semver-compare.
This appears to drop the unminified bundle sizes of 3 separate
`react-devtools-extensions` build artifacts by about 50K:
## How did you test this change?
I was originally working on [a fork of React
DevTools](https://github.com/replayio/react/pull/2) for use with
https://replay.io , specifically our integration of the React DevTools
UI to show the React component tree while users are debugging a recorded
application.
As part of the dev work on that fork, I wanted to shrink the bundle size
of the extension's generated JS build artifacts. I noted that the
official NPM `semver` library was taking up a noticeable chunk of space
in the bundles, and saw that it's only being used in a handful of places
to do some very simple version string comparisons.
I was able to replace the `semver` imports and usages with a simple
alternate comparison function, and confirmed via hands-on checks and
console logging that the checks behaved the same way.
Given that, I wanted to upstream this particular change to help shrink
the real extension's bundle sizes.
I know that it's an extension, so bundle size isn't _as_ critical a
concern as it would be for a pure library. But, smaller download sizes
do benefit all users, and that also includes sites like CodeSandbox and
Replay that are using the React DevTools as a library as well.
I'm happy to tweak this PR if necessary. Thanks!
The old version of prettier we were using didn't support the Flow syntax
to access properties in a type using `SomeType['prop']`. This updates
`prettier` and `rollup-plugin-prettier` to the latest versions.
I added the prettier config `arrowParens: "avoid"` to reduce the diff
size as the default has changed in Prettier 2.0. The largest amount of
changes comes from function expressions now having a space. This doesn't
have an option to preserve the old behavior, so we have to update this.
After the previous changes these upgrade are easy.
- removes config options that were removed
- object index access now requires an indexer key in the type, this
cause a handful of errors that were fixed
- undefined keys error in all places, this needed a few extra
suppressions for repeated undefined identifiers.
Flow's
[CHANGELOG.md](https://github.com/facebook/flow/blob/main/Changelog.md).
This enables the "exact_empty_objects" setting for Flow which makes
empty objects exact instead of building up the type as properties are
added in code below. This is in preparation to Flow 191 which makes this
the default and removes the config.
More about the change in the Flow blog
[here](https://medium.com/flow-type/improved-handling-of-the-empty-object-in-flow-ead91887e40c).
This setting is an incremental path to the next Flow version enforcing
type annotations on most functions (except some inline callbacks).
Used
```
node_modules/.bin/flow codemod annotate-functions-and-classes --write .
```
to add a majority of the types with some hand cleanup when for large
inferred objects that should just be `Fiber` or weird constructs
including `any`.
Suppressed the remaining issues.
Builds on #25918
## Summary
This PR is to fix a bug: an "element cannot be found" error when
hydrating Server Components
### The problem
<img width="1061" alt="image"
src="https://user-images.githubusercontent.com/1001890/201206046-ac32a5e3-b08a-4dc2-99f4-221dad504b28.png">
To reproduce:
1. setting up a vercel next.js 13 playground locally
https://github.com/vercel/app-playground
2. visit http://localhost:3000/loading
3. click "electronics" button to navigate to
http://localhost:3000/loading/electronics to trigger hydrating
4. inspect one of the skeleton card UI from React DevTools extension
### The root cause & fix
This bug was introduced in #22527. When syncing reconciler changes, the
value of `Hydrating` was copied from another variable `Visibility` (one
more zero in the binary number).
To avoid this kind of issue in the future, a new file `ReactFiberFlags`
is created following the same format of the one in reconciler, so that
it's easier to sync the number without making mistakes.
The reconciler fiber flag file is also updated to reflect which of the
flags are used in devtools
## How did you test this change?
I build it locally and the bug no longer exist on
http://localhost:3000/loading
* Facebook -> Meta in copyright
rg --files | xargs sed -i 's#Copyright (c) Facebook, Inc. and its affiliates.#Copyright (c) Meta Platforms, Inc. and affiliates.#g'
* Manual tweaks
- method unbinding is no longer supported in Flow for soundness, this added a bunch of suppressions
- Flow now prevents objects to be supertypes of interfaces/classes
ghstack-source-id: d7749cbad8
Pull Request resolved: https://github.com/facebook/react/pull/25412
This upgrade made more expressions invalidate refinements. In some
places this lead to a large number of suppressions that I automatically
suppressed and should be followed up on when the code is touched.
I think most of them might require either manual annotations or moving
a value into a const to allow refinement.
ghstack-source-id: a45b40abf0
Pull Request resolved: https://github.com/facebook/react/pull/25410
We've recently had multiple reports where, if React DevTools was installed, unmounting large React subtrees would take a huge performance hit (ex. from 50ms to 7 seconds).
Digging in more, we realized for every fiber that unmounts, we called `untrackFibers`, which calls `clearTimeout` (and does some work manipulating a set, but this wasn't the bulk of the time). We ten call `recordUnmount`, which adds the timer back. Adding and removing the timer so many times was taking upwards of 50ms per timer add/remove call, which was resulting in exorbitant amounts of time spent in DevTools deleting subtrees.
It looks like we are calling `untrackFibers` so many times to avoid a race condition with Suspense children where we unmount them twice (first a "virtual" unmount when the suspense boundary is toggled from visible to invisible, and then an actual unmount when the new children are rendered) without modifying `fiberIDMap`. We can fix this race condition by using the `untrackFibersSet` as a lock and not calling `recordUnmount` if the fiber is in the set and hasn't been processed yet. This works because the only way fibers are added in the set is via `recordUnmount` anyway.
This PR also adds a test to make sure this change doesn't regress the previous behavior.
**Before**
**After**
This PR adds a component stack field to the `schedule-state-update` event. The algorithm is as follows:
* During profiling, whenever a state update happens collect the parents of the fiber that caused the state update and store it in a map
* After profiling finishes, post process the `schedule-state-update` event and using the parent fibers, generate the component stack by using`describeFiber`, a function that uses error throwing to get the location of the component by calling the component without props.
---
Co-authored-by: Blake Friedman <blake.friedman@gmail.com>
When we delete fibers, we will call onCommitFiberUnmount on every deleted fiber to also remove them from the element tree. However, there are some cases where fibers aren't deleted but we still want to remove them from the element tree (ex. offscreen). In the second case, we recursively remove these children during handleCommitFiberRoot.
When we remove an element, we will untrack its corresponding fiber ID. However, because of fast refresh, we don't do this immediately, opting to instead add the value to a set to process later. However, before the set has been processed, we unmount that fiber again, we will get duplicate unmounts.
To fix this, handleCommitFiberRoot explicitly flushes all the fibers in the set before starting the deletion process. We also need to do this in handleCommitFiberUnmount in case handleCommitFiberRoot gets called first.
Resolves#24428
---
For fiber types that render user code, we check the PerformedWork flag rather than the props, ref, and state to see if the fiber rendered (rather than bailing out/etc.) so we know whether we need to do things like record profile durations. ForwardRef wasn't added to this list, which caused #24428.
The Profiler has an advanced feature that shows why a component re-rendered. In the case of props and (class) state, it shows the names of props/state values that changed between renders. For hooks, DevTools tries to detect which ones may been related to the update by comparing prev/next internal hook structures.
My initial implementation tried to detect all changed hooks. In hindsight this is confusing, because only stateful hooks (e.g. useState, useReducer, and useSyncExternalStore) can schedule an update. (Other types of hooks can change between renders, but in a reactive way.) This PR changes the behavior to only report hooks that scheduled the update.
* Pass children to hydration root constructor
I already made this change for the concurrent root API in #23309. This
does the same thing for the legacy API.
Doesn't change any behavior, but I will use this in the next steps.
* Add isRootDehydrated function
Currently this does nothing except read a boolean field, but I'm about
to change this logic.
Since this is accessed by React DOM, too, I put the function in a
separate module that can be deep imported. Previously, it was accessing
the FiberRoot directly. The reason it's a separate module is to break a
circular dependency between React DOM and the reconciler.
* Allow updates at lower pri without forcing client render
Currently, if a root is updated before the shell has finished hydrating
(for example, due to a top-level navigation), we immediately revert to
client rendering. This is rare because the root is expected is finish
quickly, but not exceedingly rare because the root may be suspended.
This adds support for updating the root without forcing a client render
as long as the update has lower priority than the initial hydration,
i.e. if the update is wrapped in startTransition.
To implement this, I had to do some refactoring. The main idea here is
to make it closer to how we implement hydration in Suspense boundaries:
- I moved isDehydrated from the shared FiberRoot object to the
HostRoot's state object.
- In the begin phase, I check if the root has received an by comparing
the new children to the initial children. If they are different, we
revert to client rendering, and set isDehydrated to false using a
derived state update (a la getDerivedStateFromProps).
- There are a few places where we used to set root.isDehydrated to false
as a way to force a client render. Instead, I set the ForceClientRender
flag on the root work-in-progress fiber.
- Whenever we fall back to client rendering, I log a recoverable error.
The overall code structure is almost identical to the corresponding
logic for Suspense components.
The reason this works is because if the update has lower priority than
the initial hydration, it won't be processed during the hydration
render, so the children will be the same.
We can go even further and allow updates at _higher_ priority (though
not sync) by implementing selective hydration at the root, like we do
for Suspense boundaries: interrupt the current render, attempt hydration
at slightly higher priority than the update, then continue rendering the
update. I haven't implemented this yet, but I've structured the code in
anticipation of adding this later.
* Wrap useMutableSource logic in feature flag
Fixes this issue, where inspecting components in nested renderers results in an error. The reason for this is because we have different fiberToIDMap instances for each renderer, and owners of a component could be in different renderers.
This fix moves the fiberToIDMap and idToArbitraryFiberMap out of the attach method so there's only one instance of each for all renderers.
* Flight side of server context
* 1 more test
* rm unused function
* flow+prettier
* flow again =)
* duplicate ReactServerContext across packages
* store default value when lazily initializing server context
* .
* better comment
* derp... missing import
* rm optional chaining
* missed feature flag
* React.__SECRET_INTERNALS_DO_NOT_USE_OR_YOU_WILL_BE_FIRED ??
* add warning if non ServerContext passed into useServerContext
* pass context in as array of arrays
* make importServerContext nott pollute the global context state
* merge main
* remove useServerContext
* dont rely on object getters in ReactServerContext and disallow JSX
* add symbols to devtools + rename globalServerContextRegistry to just ContextRegistry
* gate test case as experimental
* feedback
* remove unions
* Lint
* fix oopsies (tests/lint/mismatching arguments/signatures
* lint again
* replace-fork
* remove extraneous change
* rebase
* 1 more test
* rm unused function
* flow+prettier
* flow again =)
* duplicate ReactServerContext across packages
* store default value when lazily initializing server context
* .
* better comment
* derp... missing import
* rm optional chaining
* missed feature flag
* React.__SECRET_INTERNALS_DO_NOT_USE_OR_YOU_WILL_BE_FIRED ??
* add warning if non ServerContext passed into useServerContext
* pass context in as array of arrays
* make importServerContext nott pollute the global context state
* merge main
* remove useServerContext
* dont rely on object getters in ReactServerContext and disallow JSX
* add symbols to devtools + rename globalServerContextRegistry to just ContextRegistry
* gate test case as experimental
* feedback
* remove unions
* Lint
* fix oopsies (tests/lint/mismatching arguments/signatures
* lint again
* replace-fork
* remove extraneous change
* rebase
* reinline
* rebase
* add back changes lost due to rebase being hard
* emit chunk for provider
* remove case for React provider type
* update type for SomeChunk
* enable flag with experimental
* add missing types
* fix flow type
* missing type
* t: any
* revert extraneous type change
* better type
* better type
* feedback
* change import to type import
* test?
* test?
* remove react-dom
* remove react-native-renderer from react-server-native-relay/package.json
* gate change in FiberNewContext, getComponentNameFromType, use switch statement in FlightServer
* getComponentNameFromTpe: server context type gated and use displayName if available
* fallthrough
* lint....
* POP
* lint
- Add Tracing Marker component type to React exports
- Add reconciler work tag
- Add devtools work tag
- Add boilerplate for the cache to render children
No functionality yet
Refactor DevTools to record Timeline data (in memory) while profiling. Updated the Profiler UI to import/export Timeline data along with legacy profiler data.
Relates to issue #22529
Previously we crawled all subtrees, even not-yet-mounted ones, to initialize context values. This was not only unecessary, but it also caused an error to be thrown. This commit adds a test and fixes that behavior.
There was a bug that occurred when a destroy effect is called that causes an update. The update would be added to the updaters list even though the fiber that was calling the destroy effect was unmounted and no longer exists. This PR:
* Adds a patch to Devtools to filter out all in the update list that aren't in the fiberToIDMap (which contains all fibers currently on screen)
Until now, DEV and PROFILING builds of React recorded Timeline profiling data using the User Timing API. This commit changes things so that React records this data by calling methods on the DevTools hook. (For now, DevTools still records that data using the User Timing API, to match previous behavior.)
This commit is large but most of it is just moving things around:
* New methods have been added to the DevTools hook (in "backend/profilingHooks") for recording the Timeline performance events.
* Reconciler's "ReactFiberDevToolsHook" has been updated to call these new methods (when they're present).
* User Timing method calls in "SchedulingProfiler" have been moved to DevTools "backend/profilingHooks" (to match previous behavior, for now).
* The old reconciler tests, "SchedulingProfiler-test" and "SchedulingProfilerLabels-test", have been moved into DevTools "TimelineProfiler-test" to ensure behavior didn't change unexpectedly.
* Two new methods have been added to the injected renderer interface: injectProfilingHooks() and getLaneLabelMap().
Relates to #22529.
Adds the concept of subtree modes to DevTools to bridge protocol as follows:
1. Add-root messages get two new attributes: one specifying whether the root is running in strict mode and another specifying whether the root (really the root's renderer) supports the concept of strict mode.
2. A new backend message type (TREE_OPERATION_SET_SUBTREE_MODE). This type specifies a subtree root (id) and a mode (bitmask). For now, the only mode this message deals with is strict mode.
The DevTools frontend has been updated as well to highlight non-StrictMode compliant components.
The changes to the bridge protocol require incrementing the bridge protocol version number, which will also require updating the version of react-devtools-core backend that is shipped with React Native.
Adds the concept of "plugins" to the inspected element payload. Also adds the first plugin, one that resolves StyleX atomic style names to their values and displays them as a unified style object (rather than a nested array of objects and booleans).
Source file names are displayed first, in dim color, followed by an ordered set of resolved style values.
For builds with the new feature flag disabled, there is no observable change.
A next step to build on top of this could be to make the style values editable, but change the logic such that editing one directly added an inline style to the item (rather than modifying the stylex class– which may be shared between multiple other components).
Note that this only fixes things for newer versions of React (e.g. 18 alpha). Older versions will remain broken because there's not a good way to read the most recent context value for a location in the tree after render has completed. This is because React maintains a stack of context values during render, but by the time DevTools is called– render has finished and the stack is empty.
Changes our text encoding approach to properly support multibyte characters following this algorithm. Based on benchmarking, this new approach is roughly equivalent in terms of performance (sometimes slightly faster, sometimes slightly slower).
I also considered using TextEncoder/TextDecoder for this, but it was much slower (~85%).
* Revise ESLint rules for string coercion
Currently, react uses `'' + value` to coerce mixed values to strings.
This code will throw for Temporal objects or symbols.
To make string-coercion safer and to improve user-facing error messages,
This commit adds a new ESLint rule called `safe-string-coercion`.
This rule has two modes: a production mode and a non-production mode.
* If the `isProductionUserAppCode` option is true, then `'' + value`
coercions are allowed (because they're faster, although they may
throw) and `String(value)` coercions are disallowed. Exception:
when building error messages or running DEV-only code in prod
files, `String()` should be used because it won't throw.
* If the `isProductionUserAppCode` option is false, then `'' + value`
coercions are disallowed (because they may throw, and in non-prod
code it's not worth the risk) and `String(value)` are allowed.
Production mode is used for all files which will be bundled with
developers' userland apps. Non-prod mode is used for all other React
code: tests, DEV blocks, devtools extension, etc.
In production mode, in addiiton to flagging `String(value)` calls,
the rule will also flag `'' + value` or `value + ''` coercions that may
throw. The rule is smart enough to silence itself in the following
"will never throw" cases:
* When the coercion is wrapped in a `typeof` test that restricts to safe
(non-symbol, non-object) types. Example:
if (typeof value === 'string' || typeof value === 'number') {
thisWontReport('' + value);
}
* When what's being coerced is a unary function result, because unary
functions never return an object or a symbol.
* When the coerced value is a commonly-used numeric identifier:
`i`, `idx`, or `lineNumber`.
* When the statement immeidately before the coercion is a DEV-only
call to a function from shared/CheckStringCoercion.js. This call is a
no-op in production, but in DEV it will show a console error
explaining the problem, then will throw right after a long explanatory
code comment so that debugger users will have an idea what's going on.
The check function call must be in the following format:
if (__DEV__) {
checkXxxxxStringCoercion(value);
};
Manually disabling the rule is usually not necessary because almost all
prod use of the `'' + value` pattern falls into one of the categories
above. But in the rare cases where the rule isn't smart enough to detect
safe usage (e.g. when a coercion is inside a nested ternary operator),
manually disabling the rule will be needed.
The rule should also be manually disabled in prod error handling code
where `String(value)` should be used for coercions, because it'd be
bad to throw while building an error message or stack trace!
The prod and non-prod modes have differentiated error messages to
explain how to do a proper coercion in that mode.
If a production check call is needed but is missing or incorrect
(e.g. not in a DEV block or not immediately before the coercion), then
a context-sensitive error message will be reported so that developers
can figure out what's wrong and how to fix the problem.
Because string coercions are now handled by the `safe-string-coercion`
rule, the `no-primitive-constructor` rule no longer flags `String()`
usage. It still flags `new String(value)` because that usage is almost
always a bug.
* Add DEV-only string coercion check functions
This commit adds DEV-only functions to check whether coercing
values to strings using the `'' + value` pattern will throw. If it will
throw, these functions will:
1. Display a console error with a friendly error message describing
the problem and the developer can fix it.
2. Perform the coercion, which will throw. Right before the line where
the throwing happens, there's a long code comment that will help
debugger users (or others looking at the exception call stack) figure
out what happened and how to fix the problem.
One of these check functions should be called before all string coercion
of user-provided values, except when the the coercion is guaranteed not
to throw, e.g.
* if inside a typeof check like `if (typeof value === 'string')`
* if coercing the result of a unary function like `+value` or `value++`
* if coercing a variable named in a whitelist of numeric identifiers:
`i`, `idx`, or `lineNumber`.
The new `safe-string-coercion` internal ESLint rule enforces that
these check functions are called when they are required.
Only use these check functions in production code that will be bundled
with user apps. For non-prod code (and for production error-handling
code), use `String(value)` instead which may be a little slower but will
never throw.
* Add failing tests for string coercion
Added failing tests to verify:
* That input, select, and textarea elements with value and defaultValue
set to Temporal-like objects which will throw when coerced to string
using the `'' + value` pattern.
* That text elements will throw for Temporal-like objects
* That dangerouslySetInnerHTML will *not* throw for Temporal-like
objects because this value is not cast to a string before passing to
the DOM.
* That keys that are Temporal-like objects will throw
All tests above validate the friendly error messages thrown.
* Use `String(value)` for coercion in non-prod files
This commit switches non-production code from `'' + value` (which
throws for Temporal objects and symbols) to instead use `String(value)`
which won't throw for these or other future plus-phobic types.
"Non-produciton code" includes anything not bundled into user apps:
* Tests and test utilities. Note that I didn't change legacy React
test fixtures because I assumed it was good for those files to
act just like old React, including coercion behavior.
* Build scripts
* Dev tools package - In addition to switching to `String`, I also
removed special-case code for coercing symbols which is now
unnecessary.
* Add DEV-only string coercion checks to prod files
This commit adds DEV-only function calls to to check if string coercion
using `'' + value` will throw, which it will if the value is a Temporal
object or a symbol because those types can't be added with `+`.
If it will throw, then in DEV these checks will show a console error
to help the user undertsand what went wrong and how to fix the
problem. After emitting the console error, the check functions will
retry the coercion which will throw with a call stack that's easy (or
at least easier!) to troubleshoot because the exception happens right
after a long comment explaining the issue. So whether the user is in
a debugger, looking at the browser console, or viewing the in-browser
DEV call stack, it should be easy to understand and fix the problem.
In most cases, the safe-string-coercion ESLint rule is smart enough to
detect when a coercion is safe. But in rare cases (e.g. when a coercion
is inside a ternary) this rule will have to be manually disabled.
This commit also switches error-handling code to use `String(value)`
for coercion, because it's bad to crash when you're trying to build
an error message or a call stack! Because `String()` is usually
disallowed by the `safe-string-coercion` ESLint rule in production
code, the rule must be disabled when `String()` is used.
Previously, DevTools always overrode the native console to dim or supress StrictMode double logging. It also overrode console.log (in addition to console.error and console.warn). However, this changes the location shown by the browser console, which causes a bad developer experience. There is currently a TC39 proposal that would allow us to extend console without breaking developer experience, but in the meantime this PR changes the StrictMode console override behavior so that we only patch the console during the StrictMode double render so that, during the first render, the location points to developer code rather than our DevTools console code.
Jan Kassens
