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Update on "[compiler] Validate against JSX in try statements"
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Per comments on the new validation pass, this disallows creating JSX (expression/fragment) within a try statement. Developers sometimes use this pattern thinking that they can catch errors during the rendering of the element, without realizing that rendering is lazy. The validation allows us to teach developers about the error boundary pattern.

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@josephsavona
josephsavona committed Aug 17, 2024
2 parents 56d58aa + ff3e29d commit 1c3d4bd
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Showing 2 changed files with 159 additions and 92 deletions.
43 changes: 23 additions & 20 deletions packages/react-devtools-shared/src/__tests__/inspectedElement-test.js
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Original file line number Diff line number Diff line change
Expand Up @@ -2893,26 +2893,29 @@ describe('InspectedElement', () => {
`);

const inspectedElement = await inspectElementAtIndex(4);
expect(inspectedElement.owners).toMatchInlineSnapshot(`
[
{
"compiledWithForget": false,
"displayName": "Child",
"hocDisplayNames": null,
"id": 8,
"key": null,
"type": 5,
},
{
"compiledWithForget": false,
"displayName": "App",
"hocDisplayNames": null,
"id": 7,
"key": null,
"type": 5,
},
]
`);
// TODO: Ideally this should match the owners of the Group but those are
// part of a different parent tree. Ideally the Group would be parent of
// that parent tree though which would fix this issue.
//
// [
// {
// "compiledWithForget": false,
// "displayName": "Child",
// "hocDisplayNames": null,
// "id": 8,
// "key": null,
// "type": 5,
// },
// {
// "compiledWithForget": false,
// "displayName": "App",
// "hocDisplayNames": null,
// "id": 7,
// "key": null,
// "type": 5,
// },
// ]
expect(inspectedElement.owners).toMatchInlineSnapshot(`[]`);
});

describe('error boundary', () => {
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208 changes: 136 additions & 72 deletions packages/react-devtools-shared/src/backend/fiber/renderer.js
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Original file line number Diff line number Diff line change
Expand Up @@ -2143,29 +2143,18 @@ export function attach(
const {key} = fiber;
const displayName = getDisplayNameForFiber(fiber);
const elementType = getElementTypeForFiber(fiber);
const debugOwner = fiber._debugOwner;

// Ideally we should call getFiberIDThrows() for _debugOwner,
// since owners are almost always higher in the tree (and so have already been processed),
// but in some (rare) instances reported in open source, a descendant mounts before an owner.
// Since this is a DEV only field it's probably okay to also just lazily generate and ID here if needed.
// See https://github.com/facebook/react/issues/21445
let ownerID: number;
if (debugOwner != null) {
if (typeof debugOwner.tag === 'number') {
const ownerFiberInstance = getFiberInstanceUnsafe((debugOwner: any));
if (ownerFiberInstance !== null) {
ownerID = ownerFiberInstance.id;
} else {
ownerID = 0;
}
} else {
// TODO: Track Server Component Owners.
ownerID = 0;
}
} else {
ownerID = 0;
}

// Finding the owner instance might require traversing the whole parent path which
// doesn't have great big O notation. Ideally we'd lazily fetch the owner when we
// need it but we have some synchronous operations in the front end like Alt+Left
// which selects the owner immediately. Typically most owners are only a few parents
// away so maybe it's not so bad.
const debugOwner = getUnfilteredOwner(fiber);
const ownerInstance = findNearestOwnerInstance(
parentInstance,
debugOwner,
);
const ownerID = ownerInstance === null ? 0 : ownerInstance.id;
const parentID = parentInstance ? parentInstance.id : 0;

const displayNameStringID = getStringID(displayName);
Expand Down Expand Up @@ -2231,11 +2220,15 @@ export function attach(
displayName = env + '(' + displayName + ')';
}
const elementType = ElementTypeVirtual;
// TODO: Support Virtual Owners. To do this we need to find a matching
// virtual instance which is not a super cheap parent traversal and so
// we should ideally only do that lazily. We should maybe change the
// frontend to get it lazily.
const ownerID: number = 0;

// Finding the owner instance might require traversing the whole parent path which
// doesn't have great big O notation. Ideally we'd lazily fetch the owner when we
// need it but we have some synchronous operations in the front end like Alt+Left
// which selects the owner immediately. Typically most owners are only a few parents
// away so maybe it's not so bad.
const debugOwner = getUnfilteredOwner(componentInfo);
const ownerInstance = findNearestOwnerInstance(parentInstance, debugOwner);
const ownerID = ownerInstance === null ? 0 : ownerInstance.id;
const parentID = parentInstance ? parentInstance.id : 0;

const displayNameStringID = getStringID(displayName);
Expand Down Expand Up @@ -3354,11 +3347,19 @@ export function attach(
}

function getUpdatersList(root: any): Array<SerializedElement> | null {
return root.memoizedUpdaters != null
? Array.from(root.memoizedUpdaters)
.filter(fiber => getFiberIDUnsafe(fiber) !== null)
.map(fiberToSerializedElement)
: null;
const updaters = root.memoizedUpdaters;
if (updaters == null) {
return null;
}
const result = [];
// eslint-disable-next-line no-for-of-loops/no-for-of-loops
for (const updater of updaters) {
const inst = getFiberInstanceUnsafe(updater);
if (inst !== null) {
result.push(instanceToSerializedElement(inst));
}
}
return result;
}

function handleCommitFiberUnmount(fiber: any) {
Expand Down Expand Up @@ -3923,13 +3924,26 @@ export function attach(
}
}

function fiberToSerializedElement(fiber: Fiber): SerializedElement {
return {
displayName: getDisplayNameForFiber(fiber) || 'Anonymous',
id: getFiberIDThrows(fiber),
key: fiber.key,
type: getElementTypeForFiber(fiber),
};
function instanceToSerializedElement(
instance: DevToolsInstance,
): SerializedElement {
if (instance.kind === FIBER_INSTANCE) {
const fiber = instance.data;
return {
displayName: getDisplayNameForFiber(fiber) || 'Anonymous',
id: instance.id,
key: fiber.key,
type: getElementTypeForFiber(fiber),
};
} else {
const componentInfo = instance.data;
return {
displayName: componentInfo.name || 'Anonymous',
id: instance.id,
key: componentInfo.key == null ? null : componentInfo.key,
type: ElementTypeVirtual,
};
}
}

function getOwnersList(id: number): Array<SerializedElement> | null {
Expand All @@ -3938,33 +3952,97 @@ export function attach(
console.warn(`Could not find DevToolsInstance with id "${id}"`);
return null;
}
if (devtoolsInstance.kind !== FIBER_INSTANCE) {
// TODO: Handle VirtualInstance.
return null;
const self = instanceToSerializedElement(devtoolsInstance);
const owners = getOwnersListFromInstance(devtoolsInstance);
// This is particular API is prefixed with the current instance too for some reason.
if (owners === null) {
return [self];
}
const fiber =
findCurrentFiberUsingSlowPathByFiberInstance(devtoolsInstance);
if (fiber == null) {
owners.unshift(self);
owners.reverse();
return owners;
}

function getOwnersListFromInstance(
instance: DevToolsInstance,
): Array<SerializedElement> | null {
let owner = getUnfilteredOwner(instance.data);
if (owner === null) {
return null;
}
const owners: Array<SerializedElement> = [];
let parentInstance: null | DevToolsInstance = instance.parent;
while (parentInstance !== null && owner !== null) {
const ownerInstance = findNearestOwnerInstance(parentInstance, owner);
if (ownerInstance !== null) {
owners.push(instanceToSerializedElement(ownerInstance));
// Get the next owner and keep searching from the previous match.
owner = getUnfilteredOwner(owner);
parentInstance = ownerInstance.parent;
} else {
break;
}
}
return owners;
}

const owners: Array<SerializedElement> = [fiberToSerializedElement(fiber)];

let owner = fiber._debugOwner;
while (owner != null) {
function getUnfilteredOwner(
owner: ReactComponentInfo | Fiber | null | void,
): ReactComponentInfo | Fiber | null {
if (owner == null) {
return null;
}
if (typeof owner.tag === 'number') {
const ownerFiber: Fiber = (owner: any); // Refined
owner = ownerFiber._debugOwner;
} else {
const ownerInfo: ReactComponentInfo = (owner: any); // Refined
owner = ownerInfo.owner;
}
while (owner) {
if (typeof owner.tag === 'number') {
const ownerFiber: Fiber = (owner: any); // Refined
if (!shouldFilterFiber(ownerFiber)) {
owners.unshift(fiberToSerializedElement(ownerFiber));
return ownerFiber;
}
owner = ownerFiber._debugOwner;
} else {
// TODO: Track Server Component Owners.
break;
const ownerInfo: ReactComponentInfo = (owner: any); // Refined
if (!shouldFilterVirtual(ownerInfo)) {
return ownerInfo;
}
owner = ownerInfo.owner;
}
}
return null;
}

return owners;
function findNearestOwnerInstance(
parentInstance: null | DevToolsInstance,
owner: void | null | ReactComponentInfo | Fiber,
): null | DevToolsInstance {
if (owner == null) {
return null;
}
// Search the parent path for any instance that matches this kind of owner.
while (parentInstance !== null) {
if (
parentInstance.data === owner ||
// Typically both owner and instance.data would refer to the current version of a Fiber
// but it is possible for memoization to ignore the owner on the JSX. Then the new Fiber
// isn't propagated down as the new owner. In that case we might match the alternate
// instead. This is a bit hacky but the fastest check since type casting owner to a Fiber
// needs a duck type check anyway.
parentInstance.data === (owner: any).alternate
) {
return parentInstance;
}
parentInstance = parentInstance.parent;
}
// It is technically possible to create an element and render it in a different parent
// but this is a weird edge case and it is worth not having to scan the tree or keep
// a register for every fiber/component info.
return null;
}

// Fast path props lookup for React Native style editor.
Expand Down Expand Up @@ -4047,7 +4125,6 @@ export function attach(
}

const {
_debugOwner: debugOwner,
stateNode,
key,
memoizedProps,
Expand Down Expand Up @@ -4174,21 +4251,8 @@ export function attach(
context = {value: context};
}

let owners: null | Array<SerializedElement> = null;
let owner = debugOwner;
while (owner != null) {
if (typeof owner.tag === 'number') {
const ownerFiber: Fiber = (owner: any); // Refined
if (owners === null) {
owners = [];
}
owners.push(fiberToSerializedElement(ownerFiber));
owner = ownerFiber._debugOwner;
} else {
// TODO: Track Server Component Owners.
break;
}
}
const owners: null | Array<SerializedElement> =
getOwnersListFromInstance(fiberInstance);

const isTimedOutSuspense =
tag === SuspenseComponent && memoizedState !== null;
Expand Down Expand Up @@ -4352,8 +4416,8 @@ export function attach(
displayName = env + '(' + displayName + ')';
}

// TODO: Support Virtual Owners.
const owners: null | Array<SerializedElement> = null;
const owners: null | Array<SerializedElement> =
getOwnersListFromInstance(virtualInstance);

let rootType = null;
let targetErrorBoundaryID = null;
Expand Down

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