{"commit":{"revision":"81e442eaf3fbfabd2367a0d8691ec0df13a3add0","authorName":"Josh Story","subject":"[FlightReply] Performance improvements when decoding (#37090)","authoredAt":"2026-07-21T09:26:12-07:00","shortRevision":"81e442eaf3","authorEmail":"gnoff@storyposted.com"},"body":"Security Patches included in 19.2.8\n\nCo-authored-by: Sebastian Sebbie Silbermann ","parents":["862e275a1c150edcefab6d8ba3306192ffd6edfa"],"patch":"diff --git a\/packages\/react-server-dom-parcel\/src\/server\/ReactFlightDOMServerEdge.js b\/packages\/react-server-dom-parcel\/src\/server\/ReactFlightDOMServerEdge.js\nindex 0d2689840e..6100f4eb90 100644\n--- a\/packages\/react-server-dom-parcel\/src\/server\/ReactFlightDOMServerEdge.js\n+++ b\/packages\/react-server-dom-parcel\/src\/server\/ReactFlightDOMServerEdge.js\n@@ -21,6 +21,7 @@ import {\n type ServerReferenceId,\n } from '..\/client\/ReactFlightClientConfigBundlerParcel';\n \n+import noop from 'shared\/noop';\n import {ASYNC_ITERATOR} from 'shared\/ReactSymbols';\n \n import {\n@@ -314,7 +315,7 @@ export function decodeReplyFromAsyncIterable(\n if (typeof (iterator as any).throw === 'function') {\n \/\/ The iterator protocol doesn't necessarily include this but a generator do.\n \/\/ $FlowFixMe[prop-missing] should be able to pass mixed\n- iterator.throw(reason).then(error, error);\n+ iterator.throw(reason).then(noop, noop);\n }\n }\n \ndiff --git a\/packages\/react-server-dom-parcel\/src\/server\/ReactFlightDOMServerNode.js b\/packages\/react-server-dom-parcel\/src\/server\/ReactFlightDOMServerNode.js\nindex 3994a6ecbf..395727f69c 100644\n--- a\/packages\/react-server-dom-parcel\/src\/server\/ReactFlightDOMServerNode.js\n+++ b\/packages\/react-server-dom-parcel\/src\/server\/ReactFlightDOMServerNode.js\n@@ -24,6 +24,7 @@ import type {Duplex} from 'stream';\n \n import {Readable} from 'stream';\n \n+import noop from 'shared\/noop';\n import {ASYNC_ITERATOR} from 'shared\/ReactSymbols';\n \n import {\n@@ -772,7 +773,7 @@ export function decodeReplyFromAsyncIterable(\n if (typeof (iterator as any).throw === 'function') {\n \/\/ The iterator protocol doesn't necessarily include this but a generator do.\n \/\/ $FlowFixMe[prop-missing] should be able to pass mixed\n- iterator.throw(reason).then(error, error);\n+ iterator.throw(reason).then(noop, noop);\n }\n }\n \ndiff --git a\/packages\/react-server-dom-turbopack\/src\/server\/ReactFlightDOMServerEdge.js b\/packages\/react-server-dom-turbopack\/src\/server\/ReactFlightDOMServerEdge.js\nindex 1b2959be27..524944c1fb 100644\n--- a\/packages\/react-server-dom-turbopack\/src\/server\/ReactFlightDOMServerEdge.js\n+++ b\/packages\/react-server-dom-turbopack\/src\/server\/ReactFlightDOMServerEdge.js\n@@ -15,6 +15,7 @@ import type {Thenable} from 'shared\/ReactTypes';\n import type {ClientManifest} from '.\/ReactFlightServerConfigTurbopackBundler';\n import type {ServerManifest} from 'react-client\/src\/ReactFlightClientConfig';\n \n+import noop from 'shared\/noop';\n import {ASYNC_ITERATOR} from 'shared\/ReactSymbols';\n \n import {\n@@ -313,7 +314,7 @@ function decodeReplyFromAsyncIterable(\n if (typeof (iterator as any).throw === 'function') {\n \/\/ The iterator protocol doesn't necessarily include this but a generator do.\n \/\/ $FlowFixMe[prop-missing] should be able to pass mixed\n- iterator.throw(reason).then(error, error);\n+ iterator.throw(reason).then(noop, noop);\n }\n }\n \ndiff --git a\/packages\/react-server-dom-turbopack\/src\/server\/ReactFlightDOMServerNode.js b\/packages\/react-server-dom-turbopack\/src\/server\/ReactFlightDOMServerNode.js\nindex dfb178c742..85a4864132 100644\n--- a\/packages\/react-server-dom-turbopack\/src\/server\/ReactFlightDOMServerNode.js\n+++ b\/packages\/react-server-dom-turbopack\/src\/server\/ReactFlightDOMServerNode.js\n@@ -22,6 +22,7 @@ import type {Duplex} from 'stream';\n \n import {Readable} from 'stream';\n \n+import noop from 'shared\/noop';\n import {ASYNC_ITERATOR} from 'shared\/ReactSymbols';\n \n import {\n@@ -766,7 +767,7 @@ function decodeReplyFromAsyncIterable(\n if (typeof (iterator as any).throw === 'function') {\n \/\/ The iterator protocol doesn't necessarily include this but a generator do.\n \/\/ $FlowFixMe[prop-missing] should be able to pass mixed\n- iterator.throw(reason).then(error, error);\n+ iterator.throw(reason).then(noop, noop);\n }\n }\n \ndiff --git a\/packages\/react-server-dom-unbundled\/src\/server\/ReactFlightDOMServerNode.js b\/packages\/react-server-dom-unbundled\/src\/server\/ReactFlightDOMServerNode.js\nindex 46222148e0..e9edbcbdbb 100644\n--- a\/packages\/react-server-dom-unbundled\/src\/server\/ReactFlightDOMServerNode.js\n+++ b\/packages\/react-server-dom-unbundled\/src\/server\/ReactFlightDOMServerNode.js\n@@ -22,6 +22,7 @@ import type {Duplex} from 'stream';\n \n import {Readable} from 'stream';\n \n+import noop from 'shared\/noop';\n import {ASYNC_ITERATOR} from 'shared\/ReactSymbols';\n \n import {\n@@ -766,7 +767,7 @@ function decodeReplyFromAsyncIterable(\n if (typeof (iterator as any).throw === 'function') {\n \/\/ The iterator protocol doesn't necessarily include this but a generator do.\n \/\/ $FlowFixMe[prop-missing] should be able to pass mixed\n- iterator.throw(reason).then(error, error);\n+ iterator.throw(reason).then(noop, noop);\n }\n }\n \ndiff --git a\/packages\/react-server-dom-webpack\/src\/server\/ReactFlightDOMServerEdge.js b\/packages\/react-server-dom-webpack\/src\/server\/ReactFlightDOMServerEdge.js\nindex 933b74e2fe..22bb0656d7 100644\n--- a\/packages\/react-server-dom-webpack\/src\/server\/ReactFlightDOMServerEdge.js\n+++ b\/packages\/react-server-dom-webpack\/src\/server\/ReactFlightDOMServerEdge.js\n@@ -15,6 +15,7 @@ import type {Thenable} from 'shared\/ReactTypes';\n import type {ClientManifest} from '.\/ReactFlightServerConfigWebpackBundler';\n import type {ServerManifest} from 'react-client\/src\/ReactFlightClientConfig';\n \n+import noop from 'shared\/noop';\n import {ASYNC_ITERATOR} from 'shared\/ReactSymbols';\n \n import {\n@@ -313,7 +314,7 @@ function decodeReplyFromAsyncIterable(\n if (typeof (iterator as any).throw === 'function') {\n \/\/ The iterator protocol doesn't necessarily include this but a generator do.\n \/\/ $FlowFixMe[prop-missing] should be able to pass mixed\n- iterator.throw(reason).then(error, error);\n+ iterator.throw(reason).then(noop, noop);\n }\n }\n \ndiff --git a\/packages\/react-server-dom-webpack\/src\/server\/ReactFlightDOMServerNode.js b\/packages\/react-server-dom-webpack\/src\/server\/ReactFlightDOMServerNode.js\nindex f2551e8c6c..fcf32c342e 100644\n--- a\/packages\/react-server-dom-webpack\/src\/server\/ReactFlightDOMServerNode.js\n+++ b\/packages\/react-server-dom-webpack\/src\/server\/ReactFlightDOMServerNode.js\n@@ -22,6 +22,7 @@ import type {Duplex} from 'stream';\n \n import {Readable} from 'stream';\n \n+import noop from 'shared\/noop';\n import {ASYNC_ITERATOR} from 'shared\/ReactSymbols';\n \n import {\n@@ -767,7 +768,7 @@ function decodeReplyFromAsyncIterable(\n if (typeof (iterator as any).throw === 'function') {\n \/\/ The iterator protocol doesn't necessarily include this but a generator do.\n \/\/ $FlowFixMe[prop-missing] should be able to pass mixed\n- iterator.throw(reason).then(error, error);\n+ iterator.throw(reason).then(noop, noop);\n }\n }\n \ndiff --git a\/packages\/react-server\/src\/ReactFlightActionServer.js b\/packages\/react-server\/src\/ReactFlightActionServer.js\nindex 68fdc464ca..d00ccdfaa6 100644\n--- a\/packages\/react-server\/src\/ReactFlightActionServer.js\n+++ b\/packages\/react-server\/src\/ReactFlightActionServer.js\n@@ -112,53 +112,50 @@ export function decodeAction(\n \/\/ the implementation details of the action data.\n const formData = new FormData();\n \n- let action: Promise<(formData: FormData) => T> | null = null;\n- const seenActions = new Set();\n+ let maybeActionKey: null | string = null;\n \n \/\/ $FlowFixMe[prop-missing]\n body.forEach((value: string | File, key: string) => {\n if (!key.startsWith('$ACTION_')) {\n \/\/ $FlowFixMe[incompatible-type]\n formData.append(key, value);\n- return;\n- }\n- \/\/ Later actions may override earlier actions if a button is used to\n- \/\/ override the default form action. However, we don't expect the same\n- \/\/ action ref field to be sent multiple times in legitimate form data.\n- if (key.startsWith('$ACTION_REF_')) {\n- if (seenActions.has(key)) {\n- return;\n- }\n- seenActions.add(key);\n- const formFieldPrefix = '$ACTION_' + key.slice(12) + ':';\n- const metaData = decodeBoundActionMetaData(\n- body,\n- serverManifest,\n- formFieldPrefix,\n- );\n- action = loadServerReference(serverManifest, metaData);\n- return;\n- }\n- \/\/ A simple action with no bound arguments may appear twice in the form data\n- \/\/ if a button specifies the same action as the default form action. We only\n- \/\/ load the first one, as they're guaranteed to be identical.\n- if (key.startsWith('$ACTION_ID_')) {\n- if (seenActions.has(key)) {\n- return;\n- }\n- seenActions.add(key);\n- const id = key.slice(11);\n- action = loadServerReference(serverManifest, {\n- id,\n- bound: null,\n- });\n- return;\n+ } else if (key.startsWith('$ACTION_REF_')) {\n+ \/\/ Later actions may override earlier actions if a button is used to\n+ \/\/ override the default form action. However, we don't expect the same\n+ \/\/ action ref field to be sent multiple times in legitimate form data.\n+ maybeActionKey = key;\n+ } else if (key.startsWith('$ACTION_ID_')) {\n+ \/\/ A simple action with no bound arguments may appear twice in the form data\n+ \/\/ if a button specifies the same action as the default form action.\n+ maybeActionKey = key;\n }\n });\n \n- if (action === null) {\n+ if (maybeActionKey === null) {\n return null;\n }\n+ const actionKey = maybeActionKey;\n+\n+ let action: Promise<(formData: FormData) => T> | null = null;\n+ if (actionKey.startsWith('$ACTION_REF_')) {\n+ const formFieldPrefix =\n+ '$ACTION_' + actionKey.slice('$ACTION_REF_'.length) + ':';\n+ const metaData = decodeBoundActionMetaData(\n+ body,\n+ serverManifest,\n+ formFieldPrefix,\n+ );\n+ action = loadServerReference(serverManifest, metaData);\n+ } else if (actionKey.startsWith('$ACTION_ID_')) {\n+ const id = actionKey.slice('$ACTION_ID_'.length);\n+ action = loadServerReference(serverManifest, {\n+ id,\n+ bound: null,\n+ });\n+ } else {\n+ throw new Error('Cannot handle action key. This is a bug in React.');\n+ }\n+\n \/\/ Return the action with the remaining FormData bound to the first argument.\n return action.then(fn => fn.bind(null, formData));\n }\n@@ -175,24 +172,28 @@ export function decodeFormState(\n }\n \/\/ Search through the form data object to get the reference id and the number\n \/\/ of bound arguments. This repeats some of the work done in decodeAction.\n- let metaData = null;\n+ let actionKey: null | string = null;\n \/\/ $FlowFixMe[prop-missing]\n body.forEach((value: string | File, key: string) => {\n if (key.startsWith('$ACTION_REF_')) {\n- const formFieldPrefix = '$ACTION_' + key.slice(12) + ':';\n- metaData = decodeBoundActionMetaData(\n- body,\n- serverManifest,\n- formFieldPrefix,\n- );\n+ actionKey = key;\n }\n \/\/ We don't check for the simple $ACTION_ID_ case because form state actions\n \/\/ are always bound to the state argument.\n });\n- if (metaData === null) {\n+ if (actionKey === null) {\n \/\/ Should be unreachable.\n return Promise.resolve(null);\n }\n+\n+ const formFieldPrefix =\n+ '$ACTION_' + actionKey.slice('$ACTION_REF_'.length) + ':';\n+ const metaData = decodeBoundActionMetaData(\n+ body,\n+ serverManifest,\n+ formFieldPrefix,\n+ );\n+\n const referenceId = metaData.id;\n return Promise.resolve(metaData.bound).then(bound => {\n if (bound === null) {\ndiff --git a\/packages\/react-server\/src\/ReactFlightServer.js b\/packages\/react-server\/src\/ReactFlightServer.js\nindex 9e43d54b20..726c7dcdc1 100644\n--- a\/packages\/react-server\/src\/ReactFlightServer.js\n+++ b\/packages\/react-server\/src\/ReactFlightServer.js\n@@ -1404,7 +1404,7 @@ function serializeAsyncIterable(\n if (typeof (iterator as any).throw === 'function') {\n \/\/ The iterator protocol doesn't necessarily include this but a generator do.\n \/\/ $FlowFixMe[prop-missing] should be able to pass mixed\n- iterator.throw(reason).then(error, error);\n+ iterator.throw(reason).then(noop, noop);\n }\n }\n function abortIterable() {\n@@ -1424,9 +1424,11 @@ function serializeAsyncIterable(\n enqueueFlush(request);\n }\n if (typeof (iterator as any).throw === 'function') {\n+ \/\/ TODO: Premature exits should call return() on the iterator if it exists\n+ \/\/ to allow cleanup. See https:\/\/tc39.es\/ecma262\/multipage\/control-abstraction-objects.html#table-async-iterator-optional\n \/\/ The iterator protocol doesn't necessarily include this but a generator do.\n \/\/ $FlowFixMe[prop-missing] should be able to pass mixed\n- iterator.throw(reason).then(error, error);\n+ iterator.throw(reason).then(noop, noop);\n }\n }\n request.cacheController.signal.addEventListener('abort', abortIterable);\ndiff --git a\/scripts\/error-codes\/codes.json b\/scripts\/error-codes\/codes.json\nindex f475821238..c5be606813 100644\n--- a\/scripts\/error-codes\/codes.json\n+++ b\/scripts\/error-codes\/codes.json\n@@ -586,5 +586,6 @@\n \"598\": \"Maximum update depth exceeded. This could be an infinite loop. This can happen when a component repeatedly calls setState during render phase or inside useLayoutEffect, causing infinite render loop. React limits the number of nested updates to prevent infinite loops.\",\n \"599\": \"Expected an initialized chunk but got an initialized stream chunk instead. This payload may have been submitted by an older version of React.\",\n \"600\": \"A rejected Promise was passed to React without a `reason` property. React threw a generic error from where the Promise was used to assist in identifying the problematic Promise. Make sure that instrumented Promises correctly set the `reason` property when setting `status` to `'rejected'`.\",\n- \"601\": \"A chunk pair is incomplete. This is a bug in React.\"\n+ \"601\": \"A chunk pair is incomplete. This is a bug in React.\",\n+ \"602\": \"Cannot handle action key. This is a bug in React.\"\n }\n","files":[{"path":"packages\/react-server-dom-parcel\/src\/server\/ReactFlightDOMServerEdge.js","status":"M"},{"path":"packages\/react-server-dom-parcel\/src\/server\/ReactFlightDOMServerNode.js","status":"M"},{"path":"packages\/react-server-dom-turbopack\/src\/server\/ReactFlightDOMServerEdge.js","status":"M"},{"path":"packages\/react-server-dom-turbopack\/src\/server\/ReactFlightDOMServerNode.js","status":"M"},{"path":"packages\/react-server-dom-unbundled\/src\/server\/ReactFlightDOMServerNode.js","status":"M"},{"path":"packages\/react-server-dom-webpack\/src\/server\/ReactFlightDOMServerEdge.js","status":"M"},{"path":"packages\/react-server-dom-webpack\/src\/server\/ReactFlightDOMServerNode.js","status":"M"},{"path":"packages\/react-server\/src\/ReactFlightActionServer.js","status":"M"},{"path":"packages\/react-server\/src\/ReactFlightServer.js","status":"M"},{"path":"scripts\/error-codes\/codes.json","status":"M"}]}

dillon1000/react

Files changed