[Flight] Warn once if eval is disabled in dev environment (#35661)

Author: eps1lon

packages/react-client/src/ReactClientDebugConfigBrowser.js

@@ -0,0 +1,36 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'If this page was served with a `Content-Security-Policy` header, '+
+'make sure that `unsafe-eval` is included. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactClientDebugConfigNode.js

@@ -0,0 +1,36 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'This can happen if you started the Node.js process with --disallow-code-generation-from-strings, '+
+'or if `eval` was patched by other means. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactClientDebugConfigPlain.js

@@ -0,0 +1,34 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactFlightClient.js

@@ -61,6 +61,7 @@ import {
 bindToConsole,
 rendererVersion,
 rendererPackageName,
+checkEvalAvailabilityOnceDev,
 }from'./ReactFlightClientConfig';
 
 import{
@@ -2768,6 +2769,14 @@ export function createResponse(
 debugEndTime: void|number,// DEV-only
 debugChannel: void|DebugChannel,// DEV-only
 ): WeakResponse{
+if(__DEV__){
+// We use eval to create fake function stacks which includes Component stacks.
+// A warning would be noise if you used Flight without Components and don't encounter
+// errors. We're warning eagerly so that you configure your environment accordingly
+// before you encounter an error.
+checkEvalAvailabilityOnceDev();
+}
+
 returngetWeakResponse(
 // $FlowFixMe[invalid-constructor]: the shapes are exact here but Flow doesn't like constructors
 newResponseInstance(

packages/react-client/src/ReactFlightReplyClient.js

@@ -39,7 +39,10 @@ import getPrototypeOf from 'shared/getPrototypeOf';
 
 constObjectPrototype=Object.prototype;
 
-import{usedWithSSR}from'./ReactFlightClientConfig';
+import{
+usedWithSSR,
+checkEvalAvailabilityOnceDev,
+}from'./ReactFlightClientConfig';
 
 typeReactJSONValue=
 |string
@@ -190,6 +193,14 @@ export function processReply(
 constwrittenObjects: WeakMap<Reference,string>=newWeakMap();
 letmodelRoot: null|ReactServerValue=root;
 
+if(__DEV__){
+// We use eval to create fake function stacks which includes Component stacks.
+// A warning would be noise if you used Flight without Components and don't encounter
+// errors. We're warning eagerly so that you configure your environment accordingly
+// before you encounter an error.
+checkEvalAvailabilityOnceDev();
+}
+
 functionserializeTypedArray(
 tag: string,
 typedArray: $ArrayBufferView,

packages/react-client/src/__tests__/ReactFlight-test.js

@@ -3715,6 +3715,12 @@ describe('ReactFlight', () => {
 '\n in b (at **)'+
 '\n in a (at **)',
 );
+assertConsoleErrorDev([
+'eval() is not supported in this environment. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+]);
 }else{
 expect(receivedError.message).toEqual(
 'An error occurred in the Server Components render. The specific message is omitted in production builds to avoid leaking sensitive details. A digest property is included on this error instance which may provide additional details about the nature of the error.',

packages/react-client/src/forks/ReactFlightClientConfig.custom.js

@@ -53,3 +53,6 @@ export const bindToConsole = $$$config.bindToConsole;
 
 exportconstrendererVersion=$$$config.rendererVersion;
 exportconstrendererPackageName=$$$config.rendererPackageName;
+
+exportconstcheckEvalAvailabilityOnceDev=
+$$$config.checkEvalAvailabilityOnceDev;

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-esm.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-esm';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-esm/src/client/ReactFlightClientConfigBundlerESM';
 export*from'react-server-dom-esm/src/client/ReactFlightClientConfigTargetESMBrowser';
 export*from'react-dom-bindings/src/shared/ReactFlightClientConfigDOM';

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-parcel.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-parcel';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-parcel/src/client/ReactFlightClientConfigBundlerParcel';
 export*from'react-server-dom-parcel/src/client/ReactFlightClientConfigTargetParcelBrowser';
 export*from'react-dom-bindings/src/shared/ReactFlightClientConfigDOM';

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-turbopack.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-turbopack';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigBundlerTurbopack';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigBundlerTurbopackBrowser';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigTargetTurbopackBrowser';

packages/react-client/src/ReactClientDebugConfigBrowser.js

@@ -0,0 +1,36 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'If this page was served with a `Content-Security-Policy` header, '+
+'make sure that `unsafe-eval` is included. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactClientDebugConfigNode.js

@@ -0,0 +1,36 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'This can happen if you started the Node.js process with --disallow-code-generation-from-strings, '+
+'or if `eval` was patched by other means. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactClientDebugConfigPlain.js

@@ -0,0 +1,34 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactFlightClient.js

@@ -61,6 +61,7 @@ import {
 bindToConsole,
 rendererVersion,
 rendererPackageName,
+checkEvalAvailabilityOnceDev,
 }from'./ReactFlightClientConfig';
 
 import{
@@ -2768,6 +2769,14 @@ export function createResponse(
 debugEndTime: void|number,// DEV-only
 debugChannel: void|DebugChannel,// DEV-only
 ): WeakResponse{
+if(__DEV__){
+// We use eval to create fake function stacks which includes Component stacks.
+// A warning would be noise if you used Flight without Components and don't encounter
+// errors. We're warning eagerly so that you configure your environment accordingly
+// before you encounter an error.
+checkEvalAvailabilityOnceDev();
+}
+
 returngetWeakResponse(
 // $FlowFixMe[invalid-constructor]: the shapes are exact here but Flow doesn't like constructors
 newResponseInstance(

packages/react-client/src/ReactFlightReplyClient.js

@@ -39,7 +39,10 @@ import getPrototypeOf from 'shared/getPrototypeOf';
 
 constObjectPrototype=Object.prototype;
 
-import{usedWithSSR}from'./ReactFlightClientConfig';
+import{
+usedWithSSR,
+checkEvalAvailabilityOnceDev,
+}from'./ReactFlightClientConfig';
 
 typeReactJSONValue=
 |string
@@ -190,6 +193,14 @@ export function processReply(
 constwrittenObjects: WeakMap<Reference,string>=newWeakMap();
 letmodelRoot: null|ReactServerValue=root;
 
+if(__DEV__){
+// We use eval to create fake function stacks which includes Component stacks.
+// A warning would be noise if you used Flight without Components and don't encounter
+// errors. We're warning eagerly so that you configure your environment accordingly
+// before you encounter an error.
+checkEvalAvailabilityOnceDev();
+}
+
 functionserializeTypedArray(
 tag: string,
 typedArray: $ArrayBufferView,

packages/react-client/src/__tests__/ReactFlight-test.js

@@ -3715,6 +3715,12 @@ describe('ReactFlight', () => {
 '\n in b (at **)'+
 '\n in a (at **)',
 );
+assertConsoleErrorDev([
+'eval() is not supported in this environment. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+]);
 }else{
 expect(receivedError.message).toEqual(
 'An error occurred in the Server Components render. The specific message is omitted in production builds to avoid leaking sensitive details. A digest property is included on this error instance which may provide additional details about the nature of the error.',

packages/react-client/src/forks/ReactFlightClientConfig.custom.js

@@ -53,3 +53,6 @@ export const bindToConsole = $$$config.bindToConsole;
 
 exportconstrendererVersion=$$$config.rendererVersion;
 exportconstrendererPackageName=$$$config.rendererPackageName;
+
+exportconstcheckEvalAvailabilityOnceDev=
+$$$config.checkEvalAvailabilityOnceDev;

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-esm.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-esm';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-esm/src/client/ReactFlightClientConfigBundlerESM';
 export*from'react-server-dom-esm/src/client/ReactFlightClientConfigTargetESMBrowser';
 export*from'react-dom-bindings/src/shared/ReactFlightClientConfigDOM';

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-parcel.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-parcel';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-parcel/src/client/ReactFlightClientConfigBundlerParcel';
 export*from'react-server-dom-parcel/src/client/ReactFlightClientConfigTargetParcelBrowser';
 export*from'react-dom-bindings/src/shared/ReactFlightClientConfigDOM';

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-turbopack.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-turbopack';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigBundlerTurbopack';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigBundlerTurbopackBrowser';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigTargetTurbopackBrowser';

packages/react-client/src/ReactClientDebugConfigBrowser.js

@@ -0,0 +1,36 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'If this page was served with a `Content-Security-Policy` header, '+
+'make sure that `unsafe-eval` is included. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactClientDebugConfigNode.js

@@ -0,0 +1,36 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'This can happen if you started the Node.js process with --disallow-code-generation-from-strings, '+
+'or if `eval` was patched by other means. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactClientDebugConfigPlain.js

@@ -0,0 +1,34 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactFlightClient.js

@@ -61,6 +61,7 @@ import {
 bindToConsole,
 rendererVersion,
 rendererPackageName,
+checkEvalAvailabilityOnceDev,
 }from'./ReactFlightClientConfig';
 
 import{
@@ -2768,6 +2769,14 @@ export function createResponse(
 debugEndTime: void|number,// DEV-only
 debugChannel: void|DebugChannel,// DEV-only
 ): WeakResponse{
+if(__DEV__){
+// We use eval to create fake function stacks which includes Component stacks.
+// A warning would be noise if you used Flight without Components and don't encounter
+// errors. We're warning eagerly so that you configure your environment accordingly
+// before you encounter an error.
+checkEvalAvailabilityOnceDev();
+}
+
 returngetWeakResponse(
 // $FlowFixMe[invalid-constructor]: the shapes are exact here but Flow doesn't like constructors
 newResponseInstance(

packages/react-client/src/ReactFlightReplyClient.js

@@ -39,7 +39,10 @@ import getPrototypeOf from 'shared/getPrototypeOf';
 
 constObjectPrototype=Object.prototype;
 
-import{usedWithSSR}from'./ReactFlightClientConfig';
+import{
+usedWithSSR,
+checkEvalAvailabilityOnceDev,
+}from'./ReactFlightClientConfig';
 
 typeReactJSONValue=
 |string
@@ -190,6 +193,14 @@ export function processReply(
 constwrittenObjects: WeakMap<Reference,string>=newWeakMap();
 letmodelRoot: null|ReactServerValue=root;
 
+if(__DEV__){
+// We use eval to create fake function stacks which includes Component stacks.
+// A warning would be noise if you used Flight without Components and don't encounter
+// errors. We're warning eagerly so that you configure your environment accordingly
+// before you encounter an error.
+checkEvalAvailabilityOnceDev();
+}
+
 functionserializeTypedArray(
 tag: string,
 typedArray: $ArrayBufferView,

packages/react-client/src/__tests__/ReactFlight-test.js

@@ -3715,6 +3715,12 @@ describe('ReactFlight', () => {
 '\n in b (at **)'+
 '\n in a (at **)',
 );
+assertConsoleErrorDev([
+'eval() is not supported in this environment. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+]);
 }else{
 expect(receivedError.message).toEqual(
 'An error occurred in the Server Components render. The specific message is omitted in production builds to avoid leaking sensitive details. A digest property is included on this error instance which may provide additional details about the nature of the error.',

packages/react-client/src/forks/ReactFlightClientConfig.custom.js

@@ -53,3 +53,6 @@ export const bindToConsole = $$$config.bindToConsole;
 
 exportconstrendererVersion=$$$config.rendererVersion;
 exportconstrendererPackageName=$$$config.rendererPackageName;
+
+exportconstcheckEvalAvailabilityOnceDev=
+$$$config.checkEvalAvailabilityOnceDev;

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-esm.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-esm';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-esm/src/client/ReactFlightClientConfigBundlerESM';
 export*from'react-server-dom-esm/src/client/ReactFlightClientConfigTargetESMBrowser';
 export*from'react-dom-bindings/src/shared/ReactFlightClientConfigDOM';

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-parcel.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-parcel';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-parcel/src/client/ReactFlightClientConfigBundlerParcel';
 export*from'react-server-dom-parcel/src/client/ReactFlightClientConfigTargetParcelBrowser';
 export*from'react-dom-bindings/src/shared/ReactFlightClientConfigDOM';

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-turbopack.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-turbopack';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigBundlerTurbopack';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigBundlerTurbopackBrowser';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigTargetTurbopackBrowser';

packages/react-client/src/ReactClientDebugConfigBrowser.js

@@ -0,0 +1,36 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'If this page was served with a `Content-Security-Policy` header, '+
+'make sure that `unsafe-eval` is included. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactClientDebugConfigNode.js

@@ -0,0 +1,36 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'This can happen if you started the Node.js process with --disallow-code-generation-from-strings, '+
+'or if `eval` was patched by other means. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactClientDebugConfigPlain.js

@@ -0,0 +1,34 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactFlightClient.js

@@ -61,6 +61,7 @@ import {
 bindToConsole,
 rendererVersion,
 rendererPackageName,
+checkEvalAvailabilityOnceDev,
 }from'./ReactFlightClientConfig';
 
 import{
@@ -2768,6 +2769,14 @@ export function createResponse(
 debugEndTime: void|number,// DEV-only
 debugChannel: void|DebugChannel,// DEV-only
 ): WeakResponse{
+if(__DEV__){
+// We use eval to create fake function stacks which includes Component stacks.
+// A warning would be noise if you used Flight without Components and don't encounter
+// errors. We're warning eagerly so that you configure your environment accordingly
+// before you encounter an error.
+checkEvalAvailabilityOnceDev();
+}
+
 returngetWeakResponse(
 // $FlowFixMe[invalid-constructor]: the shapes are exact here but Flow doesn't like constructors
 newResponseInstance(

packages/react-client/src/ReactFlightReplyClient.js

@@ -39,7 +39,10 @@ import getPrototypeOf from 'shared/getPrototypeOf';
 
 constObjectPrototype=Object.prototype;
 
-import{usedWithSSR}from'./ReactFlightClientConfig';
+import{
+usedWithSSR,
+checkEvalAvailabilityOnceDev,
+}from'./ReactFlightClientConfig';
 
 typeReactJSONValue=
 |string
@@ -190,6 +193,14 @@ export function processReply(
 constwrittenObjects: WeakMap<Reference,string>=newWeakMap();
 letmodelRoot: null|ReactServerValue=root;
 
+if(__DEV__){
+// We use eval to create fake function stacks which includes Component stacks.
+// A warning would be noise if you used Flight without Components and don't encounter
+// errors. We're warning eagerly so that you configure your environment accordingly
+// before you encounter an error.
+checkEvalAvailabilityOnceDev();
+}
+
 functionserializeTypedArray(
 tag: string,
 typedArray: $ArrayBufferView,

packages/react-client/src/__tests__/ReactFlight-test.js

@@ -3715,6 +3715,12 @@ describe('ReactFlight', () => {
 '\n in b (at **)'+
 '\n in a (at **)',
 );
+assertConsoleErrorDev([
+'eval() is not supported in this environment. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+]);
 }else{
 expect(receivedError.message).toEqual(
 'An error occurred in the Server Components render. The specific message is omitted in production builds to avoid leaking sensitive details. A digest property is included on this error instance which may provide additional details about the nature of the error.',

packages/react-client/src/forks/ReactFlightClientConfig.custom.js

@@ -53,3 +53,6 @@ export const bindToConsole = $$$config.bindToConsole;
 
 exportconstrendererVersion=$$$config.rendererVersion;
 exportconstrendererPackageName=$$$config.rendererPackageName;
+
+exportconstcheckEvalAvailabilityOnceDev=
+$$$config.checkEvalAvailabilityOnceDev;

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-esm.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-esm';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-esm/src/client/ReactFlightClientConfigBundlerESM';
 export*from'react-server-dom-esm/src/client/ReactFlightClientConfigTargetESMBrowser';
 export*from'react-dom-bindings/src/shared/ReactFlightClientConfigDOM';

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-parcel.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-parcel';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-parcel/src/client/ReactFlightClientConfigBundlerParcel';
 export*from'react-server-dom-parcel/src/client/ReactFlightClientConfigTargetParcelBrowser';
 export*from'react-dom-bindings/src/shared/ReactFlightClientConfigDOM';

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-turbopack.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-turbopack';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigBundlerTurbopack';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigBundlerTurbopackBrowser';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigTargetTurbopackBrowser';

packages/react-client/src/ReactClientDebugConfigBrowser.js

@@ -0,0 +1,36 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'If this page was served with a `Content-Security-Policy` header, '+
+'make sure that `unsafe-eval` is included. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactClientDebugConfigNode.js

@@ -0,0 +1,36 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'This can happen if you started the Node.js process with --disallow-code-generation-from-strings, '+
+'or if `eval` was patched by other means. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactClientDebugConfigPlain.js

@@ -0,0 +1,34 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactFlightClient.js

@@ -61,6 +61,7 @@ import {
 bindToConsole,
 rendererVersion,
 rendererPackageName,
+checkEvalAvailabilityOnceDev,
 }from'./ReactFlightClientConfig';
 
 import{
@@ -2768,6 +2769,14 @@ export function createResponse(
 debugEndTime: void|number,// DEV-only
 debugChannel: void|DebugChannel,// DEV-only
 ): WeakResponse{
+if(__DEV__){
+// We use eval to create fake function stacks which includes Component stacks.
+// A warning would be noise if you used Flight without Components and don't encounter
+// errors. We're warning eagerly so that you configure your environment accordingly
+// before you encounter an error.
+checkEvalAvailabilityOnceDev();
+}
+
 returngetWeakResponse(
 // $FlowFixMe[invalid-constructor]: the shapes are exact here but Flow doesn't like constructors
 newResponseInstance(

packages/react-client/src/ReactFlightReplyClient.js

@@ -39,7 +39,10 @@ import getPrototypeOf from 'shared/getPrototypeOf';
 
 constObjectPrototype=Object.prototype;
 
-import{usedWithSSR}from'./ReactFlightClientConfig';
+import{
+usedWithSSR,
+checkEvalAvailabilityOnceDev,
+}from'./ReactFlightClientConfig';
 
 typeReactJSONValue=
 |string
@@ -190,6 +193,14 @@ export function processReply(
 constwrittenObjects: WeakMap<Reference,string>=newWeakMap();
 letmodelRoot: null|ReactServerValue=root;
 
+if(__DEV__){
+// We use eval to create fake function stacks which includes Component stacks.
+// A warning would be noise if you used Flight without Components and don't encounter
+// errors. We're warning eagerly so that you configure your environment accordingly
+// before you encounter an error.
+checkEvalAvailabilityOnceDev();
+}
+
 functionserializeTypedArray(
 tag: string,
 typedArray: $ArrayBufferView,

packages/react-client/src/__tests__/ReactFlight-test.js

@@ -3715,6 +3715,12 @@ describe('ReactFlight', () => {
 '\n in b (at **)'+
 '\n in a (at **)',
 );
+assertConsoleErrorDev([
+'eval() is not supported in this environment. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+]);
 }else{
 expect(receivedError.message).toEqual(
 'An error occurred in the Server Components render. The specific message is omitted in production builds to avoid leaking sensitive details. A digest property is included on this error instance which may provide additional details about the nature of the error.',

packages/react-client/src/forks/ReactFlightClientConfig.custom.js

@@ -53,3 +53,6 @@ export const bindToConsole = $$$config.bindToConsole;
 
 exportconstrendererVersion=$$$config.rendererVersion;
 exportconstrendererPackageName=$$$config.rendererPackageName;
+
+exportconstcheckEvalAvailabilityOnceDev=
+$$$config.checkEvalAvailabilityOnceDev;

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-esm.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-esm';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-esm/src/client/ReactFlightClientConfigBundlerESM';
 export*from'react-server-dom-esm/src/client/ReactFlightClientConfigTargetESMBrowser';
 export*from'react-dom-bindings/src/shared/ReactFlightClientConfigDOM';

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-parcel.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-parcel';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-parcel/src/client/ReactFlightClientConfigBundlerParcel';
 export*from'react-server-dom-parcel/src/client/ReactFlightClientConfigTargetParcelBrowser';
 export*from'react-dom-bindings/src/shared/ReactFlightClientConfigDOM';

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-turbopack.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-turbopack';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigBundlerTurbopack';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigBundlerTurbopackBrowser';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigTargetTurbopackBrowser';

packages/react-client/src/ReactClientDebugConfigBrowser.js

@@ -0,0 +1,36 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'If this page was served with a `Content-Security-Policy` header, '+
+'make sure that `unsafe-eval` is included. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactClientDebugConfigNode.js

@@ -0,0 +1,36 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'This can happen if you started the Node.js process with --disallow-code-generation-from-strings, '+
+'or if `eval` was patched by other means. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactClientDebugConfigPlain.js

@@ -0,0 +1,34 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactFlightClient.js

@@ -61,6 +61,7 @@ import {
 bindToConsole,
 rendererVersion,
 rendererPackageName,
+checkEvalAvailabilityOnceDev,
 }from'./ReactFlightClientConfig';
 
 import{
@@ -2768,6 +2769,14 @@ export function createResponse(
 debugEndTime: void|number,// DEV-only
 debugChannel: void|DebugChannel,// DEV-only
 ): WeakResponse{
+if(__DEV__){
+// We use eval to create fake function stacks which includes Component stacks.
+// A warning would be noise if you used Flight without Components and don't encounter
+// errors. We're warning eagerly so that you configure your environment accordingly
+// before you encounter an error.
+checkEvalAvailabilityOnceDev();
+}
+
 returngetWeakResponse(
 // $FlowFixMe[invalid-constructor]: the shapes are exact here but Flow doesn't like constructors
 newResponseInstance(

packages/react-client/src/ReactFlightReplyClient.js

@@ -39,7 +39,10 @@ import getPrototypeOf from 'shared/getPrototypeOf';
 
 constObjectPrototype=Object.prototype;
 
-import{usedWithSSR}from'./ReactFlightClientConfig';
+import{
+usedWithSSR,
+checkEvalAvailabilityOnceDev,
+}from'./ReactFlightClientConfig';
 
 typeReactJSONValue=
 |string
@@ -190,6 +193,14 @@ export function processReply(
 constwrittenObjects: WeakMap<Reference,string>=newWeakMap();
 letmodelRoot: null|ReactServerValue=root;
 
+if(__DEV__){
+// We use eval to create fake function stacks which includes Component stacks.
+// A warning would be noise if you used Flight without Components and don't encounter
+// errors. We're warning eagerly so that you configure your environment accordingly
+// before you encounter an error.
+checkEvalAvailabilityOnceDev();
+}
+
 functionserializeTypedArray(
 tag: string,
 typedArray: $ArrayBufferView,

packages/react-client/src/__tests__/ReactFlight-test.js

@@ -3715,6 +3715,12 @@ describe('ReactFlight', () => {
 '\n in b (at **)'+
 '\n in a (at **)',
 );
+assertConsoleErrorDev([
+'eval() is not supported in this environment. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+]);
 }else{
 expect(receivedError.message).toEqual(
 'An error occurred in the Server Components render. The specific message is omitted in production builds to avoid leaking sensitive details. A digest property is included on this error instance which may provide additional details about the nature of the error.',

packages/react-client/src/forks/ReactFlightClientConfig.custom.js

@@ -53,3 +53,6 @@ export const bindToConsole = $$$config.bindToConsole;
 
 exportconstrendererVersion=$$$config.rendererVersion;
 exportconstrendererPackageName=$$$config.rendererPackageName;
+
+exportconstcheckEvalAvailabilityOnceDev=
+$$$config.checkEvalAvailabilityOnceDev;

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-esm.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-esm';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-esm/src/client/ReactFlightClientConfigBundlerESM';
 export*from'react-server-dom-esm/src/client/ReactFlightClientConfigTargetESMBrowser';
 export*from'react-dom-bindings/src/shared/ReactFlightClientConfigDOM';

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-parcel.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-parcel';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-parcel/src/client/ReactFlightClientConfigBundlerParcel';
 export*from'react-server-dom-parcel/src/client/ReactFlightClientConfigTargetParcelBrowser';
 export*from'react-dom-bindings/src/shared/ReactFlightClientConfigDOM';

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-turbopack.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-turbopack';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigBundlerTurbopack';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigBundlerTurbopackBrowser';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigTargetTurbopackBrowser';

packages/react-client/src/ReactClientDebugConfigBrowser.js

@@ -0,0 +1,36 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'If this page was served with a `Content-Security-Policy` header, '+
+'make sure that `unsafe-eval` is included. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactClientDebugConfigNode.js

@@ -0,0 +1,36 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'This can happen if you started the Node.js process with --disallow-code-generation-from-strings, '+
+'or if `eval` was patched by other means. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactClientDebugConfigPlain.js

@@ -0,0 +1,34 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactFlightClient.js

@@ -61,6 +61,7 @@ import {
 bindToConsole,
 rendererVersion,
 rendererPackageName,
+checkEvalAvailabilityOnceDev,
 }from'./ReactFlightClientConfig';
 
 import{
@@ -2768,6 +2769,14 @@ export function createResponse(
 debugEndTime: void|number,// DEV-only
 debugChannel: void|DebugChannel,// DEV-only
 ): WeakResponse{
+if(__DEV__){
+// We use eval to create fake function stacks which includes Component stacks.
+// A warning would be noise if you used Flight without Components and don't encounter
+// errors. We're warning eagerly so that you configure your environment accordingly
+// before you encounter an error.
+checkEvalAvailabilityOnceDev();
+}
+
 returngetWeakResponse(
 // $FlowFixMe[invalid-constructor]: the shapes are exact here but Flow doesn't like constructors
 newResponseInstance(

packages/react-client/src/ReactFlightReplyClient.js

@@ -39,7 +39,10 @@ import getPrototypeOf from 'shared/getPrototypeOf';
 
 constObjectPrototype=Object.prototype;
 
-import{usedWithSSR}from'./ReactFlightClientConfig';
+import{
+usedWithSSR,
+checkEvalAvailabilityOnceDev,
+}from'./ReactFlightClientConfig';
 
 typeReactJSONValue=
 |string
@@ -190,6 +193,14 @@ export function processReply(
 constwrittenObjects: WeakMap<Reference,string>=newWeakMap();
 letmodelRoot: null|ReactServerValue=root;
 
+if(__DEV__){
+// We use eval to create fake function stacks which includes Component stacks.
+// A warning would be noise if you used Flight without Components and don't encounter
+// errors. We're warning eagerly so that you configure your environment accordingly
+// before you encounter an error.
+checkEvalAvailabilityOnceDev();
+}
+
 functionserializeTypedArray(
 tag: string,
 typedArray: $ArrayBufferView,

packages/react-client/src/__tests__/ReactFlight-test.js

@@ -3715,6 +3715,12 @@ describe('ReactFlight', () => {
 '\n in b (at **)'+
 '\n in a (at **)',
 );
+assertConsoleErrorDev([
+'eval() is not supported in this environment. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+]);
 }else{
 expect(receivedError.message).toEqual(
 'An error occurred in the Server Components render. The specific message is omitted in production builds to avoid leaking sensitive details. A digest property is included on this error instance which may provide additional details about the nature of the error.',

packages/react-client/src/forks/ReactFlightClientConfig.custom.js

@@ -53,3 +53,6 @@ export const bindToConsole = $$$config.bindToConsole;
 
 exportconstrendererVersion=$$$config.rendererVersion;
 exportconstrendererPackageName=$$$config.rendererPackageName;
+
+exportconstcheckEvalAvailabilityOnceDev=
+$$$config.checkEvalAvailabilityOnceDev;

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-esm.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-esm';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-esm/src/client/ReactFlightClientConfigBundlerESM';
 export*from'react-server-dom-esm/src/client/ReactFlightClientConfigTargetESMBrowser';
 export*from'react-dom-bindings/src/shared/ReactFlightClientConfigDOM';

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-parcel.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-parcel';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-parcel/src/client/ReactFlightClientConfigBundlerParcel';
 export*from'react-server-dom-parcel/src/client/ReactFlightClientConfigTargetParcelBrowser';
 export*from'react-dom-bindings/src/shared/ReactFlightClientConfigDOM';

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-turbopack.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-turbopack';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigBundlerTurbopack';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigBundlerTurbopackBrowser';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigTargetTurbopackBrowser';

packages/react-client/src/ReactClientDebugConfigBrowser.js

@@ -0,0 +1,36 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'If this page was served with a `Content-Security-Policy` header, '+
+'make sure that `unsafe-eval` is included. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactClientDebugConfigNode.js

@@ -0,0 +1,36 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'This can happen if you started the Node.js process with --disallow-code-generation-from-strings, '+
+'or if `eval` was patched by other means. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactClientDebugConfigPlain.js

@@ -0,0 +1,34 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+lethasConfirmedEval=false;
+exportfunctioncheckEvalAvailabilityOnceDev(): void{
+if(__DEV__){
+if(!hasConfirmedEval){
+hasConfirmedEval=true;
+try{
+// eslint-disable-next-line no-eval
+(0,eval)('null');
+}catch{
+console.error(
+'eval() is not supported in this environment. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+);
+}
+}
+}else{
+// These errors should never make it into a build so we don't need to encode them in codes.json
+// eslint-disable-next-line react-internal/prod-error-codes
+thrownewError(
+'checkEvalAvailabilityOnceDev should never be called in production mode. This is a bug in React.',
+);
+}
+}

packages/react-client/src/ReactFlightClient.js

@@ -61,6 +61,7 @@ import {
 bindToConsole,
 rendererVersion,
 rendererPackageName,
+checkEvalAvailabilityOnceDev,
 }from'./ReactFlightClientConfig';
 
 import{
@@ -2768,6 +2769,14 @@ export function createResponse(
 debugEndTime: void|number,// DEV-only
 debugChannel: void|DebugChannel,// DEV-only
 ): WeakResponse{
+if(__DEV__){
+// We use eval to create fake function stacks which includes Component stacks.
+// A warning would be noise if you used Flight without Components and don't encounter
+// errors. We're warning eagerly so that you configure your environment accordingly
+// before you encounter an error.
+checkEvalAvailabilityOnceDev();
+}
+
 returngetWeakResponse(
 // $FlowFixMe[invalid-constructor]: the shapes are exact here but Flow doesn't like constructors
 newResponseInstance(

packages/react-client/src/ReactFlightReplyClient.js

@@ -39,7 +39,10 @@ import getPrototypeOf from 'shared/getPrototypeOf';
 
 constObjectPrototype=Object.prototype;
 
-import{usedWithSSR}from'./ReactFlightClientConfig';
+import{
+usedWithSSR,
+checkEvalAvailabilityOnceDev,
+}from'./ReactFlightClientConfig';
 
 typeReactJSONValue=
 |string
@@ -190,6 +193,14 @@ export function processReply(
 constwrittenObjects: WeakMap<Reference,string>=newWeakMap();
 letmodelRoot: null|ReactServerValue=root;
 
+if(__DEV__){
+// We use eval to create fake function stacks which includes Component stacks.
+// A warning would be noise if you used Flight without Components and don't encounter
+// errors. We're warning eagerly so that you configure your environment accordingly
+// before you encounter an error.
+checkEvalAvailabilityOnceDev();
+}
+
 functionserializeTypedArray(
 tag: string,
 typedArray: $ArrayBufferView,

packages/react-client/src/__tests__/ReactFlight-test.js

@@ -3715,6 +3715,12 @@ describe('ReactFlight', () => {
 '\n in b (at **)'+
 '\n in a (at **)',
 );
+assertConsoleErrorDev([
+'eval() is not supported in this environment. '+
+'React requires eval() in development mode for various debugging features '+
+'like reconstructing callstacks from a different environment.\n'+
+'React will never use eval() in production mode',
+]);
 }else{
 expect(receivedError.message).toEqual(
 'An error occurred in the Server Components render. The specific message is omitted in production builds to avoid leaking sensitive details. A digest property is included on this error instance which may provide additional details about the nature of the error.',

packages/react-client/src/forks/ReactFlightClientConfig.custom.js

@@ -53,3 +53,6 @@ export const bindToConsole = $$$config.bindToConsole;
 
 exportconstrendererVersion=$$$config.rendererVersion;
 exportconstrendererPackageName=$$$config.rendererPackageName;
+
+exportconstcheckEvalAvailabilityOnceDev=
+$$$config.checkEvalAvailabilityOnceDev;

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-esm.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-esm';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-esm/src/client/ReactFlightClientConfigBundlerESM';
 export*from'react-server-dom-esm/src/client/ReactFlightClientConfigTargetESMBrowser';
 export*from'react-dom-bindings/src/shared/ReactFlightClientConfigDOM';

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-parcel.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-parcel';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-parcel/src/client/ReactFlightClientConfigBundlerParcel';
 export*from'react-server-dom-parcel/src/client/ReactFlightClientConfigTargetParcelBrowser';
 export*from'react-dom-bindings/src/shared/ReactFlightClientConfigDOM';

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser-turbopack.js

@@ -12,6 +12,7 @@ export const rendererPackageName = 'react-server-dom-turbopack';
 
 export*from'react-client/src/ReactFlightClientStreamConfigWeb';
 export*from'react-client/src/ReactClientConsoleConfigBrowser';
+export*from'react-client/src/ReactClientDebugConfigBrowser';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigBundlerTurbopack';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigBundlerTurbopackBrowser';
 export*from'react-server-dom-turbopack/src/client/ReactFlightClientConfigTargetTurbopackBrowser';