Don't try writing if the stream is full

Author: devknoll

packages/react-dom/src/server/ReactDOMLegacyServerStreamConfig.js

@@ -22,7 +22,9 @@ export function scheduleWork(callback: () => void) {
 
 export function flushBuffered(destination: Destination) {}
 
-export function beginWriting(destination: Destination) {}
+export function beginWriting(destination: Destination): boolean {
+  return true;
+}
 
 let prevWasCommentSegmenter = false;
 export function writeChunk(

packages/react-noop-renderer/src/ReactNoopFlightServer.js

@@ -26,7 +26,9 @@ const ReactNoopFlightServer = ReactFlightServer({
   scheduleWork(callback: () => void) {
     callback();
   },
-  beginWriting(destination: Destination): void {},
+  beginWriting(destination: Destination): boolean {
+    return true;
+  },
   writeChunk(destination: Destination, chunk: string): void {
     destination.push(chunk);
   },

packages/react-noop-renderer/src/ReactNoopServer.js

@@ -57,7 +57,9 @@ const ReactNoopServer = ReactFizzServer({
   scheduleWork(callback: () => void) {
     callback();
   },
-  beginWriting(destination: Destination): void {},
+  beginWriting(destination: Destination): boolean {
+    return true;
+  },
   writeChunk(destination: Destination, buffer: Uint8Array): void {
     const stack = destination.stack;
     if (buffer === POP) {

packages/react-server-dom-relay/src/ReactFlightDOMRelayServerHostConfig.js

@@ -139,7 +139,9 @@ export function scheduleWork(callback: () => void) {
 
 export function flushBuffered(destination: Destination) {}
 
-export function beginWriting(destination: Destination) {}
+export function beginWriting(destination: Destination): boolean {
+  return true;
+}
 
 export function writeChunk(destination: Destination, chunk: Chunk): boolean {
   emitRow(destination, chunk);

packages/react-server-dom-relay/src/ReactServerStreamConfigFB.js

@@ -23,7 +23,9 @@ export function scheduleWork(callback: () => void) {
 
 export function flushBuffered(destination: Destination) {}
 
-export function beginWriting(destination: Destination) {}
+export function beginWriting(destination: Destination): boolean {
+  return true;
+}
 
 export function writeChunk(
   destination: Destination,

packages/react-server-native-relay/src/ReactFlightNativeRelayServerHostConfig.js

@@ -136,7 +136,9 @@ export function scheduleWork(callback: () => void) {
 
 export function flushBuffered(destination: Destination) {}
 
-export function beginWriting(destination: Destination) {}
+export function beginWriting(destination: Destination): boolean {
+  return true;
+}
 
 export function writeChunk(destination: Destination, chunk: Chunk): boolean {
   emitRow(destination, chunk);

packages/react-server/src/ReactFizzServer.js

@@ -1820,7 +1820,10 @@ function flushCompletedQueues(
   request: Request,
   destination: Destination,
 ): void {
-  beginWriting(destination);
+  if (!beginWriting(destination)) {
+    request.destination = null;
+    return;
+  }
   try {
     // The structure of this is to go through each queue one by one and write
     // until the sink tells us to stop. When we should stop, we still finish writing
@@ -1872,7 +1875,10 @@ function flushCompletedQueues(
     // Allow anything written so far to flush to the underlying sink before
     // we continue with lower priorities.
     completeWriting(destination);
-    beginWriting(destination);
+    if (!beginWriting(destination)) {
+      request.destination = null;
+      return;
+    }
 
     // TODO: Here we'll emit data used by hydration.
 

packages/react-server/src/ReactFlightServer.js

@@ -723,7 +723,10 @@ function flushCompletedChunks(
   request: Request,
   destination: Destination,
 ): void {
-  beginWriting(destination);
+  if (!beginWriting(destination)) {
+    request.destination = null;
+    return;
+  }
   try {
     // We emit module chunks first in the stream so that
     // they can be preloaded as early as possible.

packages/react-server/src/ReactServerStreamConfigBrowser.js

@@ -21,7 +21,9 @@ export function flushBuffered(destination: Destination) {
   // transform streams. https://github.com/whatwg/streams/issues/960
 }
 
-export function beginWriting(destination: Destination) {}
+export function beginWriting(destination: Destination): boolean {
+  return destination.desiredSize > 0;
+}
 
 export function writeChunk(
   destination: Destination,

packages/react-server/src/ReactServerStreamConfigNode.js

@@ -9,12 +9,13 @@
 
 import type {Writable} from 'stream';
 
-type MightBeFlushable = {
+type WritableExtensions = {
   flush?: () => void,
+  writableNeedDrain?: boolean,
   ...
 };
 
-export type Destination = Writable & MightBeFlushable;
+export type Destination = Writable & WritableExtensions;
 
 export type PrecomputedChunk = Uint8Array;
 export type Chunk = string;
@@ -33,11 +34,16 @@ export function flushBuffered(destination: Destination) {
   }
 }
 
-export function beginWriting(destination: Destination) {
-  // Older Node streams like http.createServer don't have this.
-  if (typeof destination.cork === 'function') {
-    destination.cork();
+export function beginWriting(destination: Destination): boolean {
+  // Older versions of Node don't have this.
+  if (destination.writableNeedDrain !== true) {
+    // Older Node streams like http.createServer don't have this.
+    if (typeof destination.cork === 'function') {
+      destination.cork();
+    }
+    return true;
   }
+  return false;
 }
 
 export function writeChunk(