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fix: enhance stream handling with safe enqueue and close mechanisms #7893

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merged 1 commit into from
Nov 19, 2025
Merged

fix: enhance stream handling with safe enqueue and close mechanisms #7893

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110 changes: 73 additions & 37 deletions packages/runtime/plugin-runtime/src/core/server/stream/createReadableStream.worker.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -68,9 +68,38 @@ export const createReadableStreamFromElement: CreateReadableStreamFromElement =
const stream = new ReadableStream({
start(controller) {
const pendingScripts: string[] = [];
let isClosed = false;

const safeEnqueue = (chunk: Uint8Array | unknown) => {
if (isClosed) return;
try {
controller.enqueue(chunk as Uint8Array);
} catch {
isClosed = true;
}
};

const closeController = () => {
if (!isClosed) {
isClosed = true;
try {
controller.close();
} catch {
// Controller already closed
}
}
};

const flushPendingScripts = () => {
for (const s of pendingScripts) {
safeEnqueue(encodeForWebStream(s));
}
pendingScripts.length = 0;
};

const enqueueScript = (script: string) => {
if (shellChunkStatus === ShellChunkStatus.FINISH) {
controller.enqueue(encodeForWebStream(script));
safeEnqueue(encodeForWebStream(script));
} else {
pendingScripts.push(script);
}
Expand All @@ -93,51 +122,58 @@ export const createReadableStreamFromElement: CreateReadableStreamFromElement =
: [];

if (entries.length > 0) {
enqueueFromEntries(entries, config.nonce, (s: string) =>
enqueueScript(s),
);
enqueueFromEntries(entries, config.nonce, enqueueScript);
}

async function push() {
const { done, value } = await reader.read();
if (done) {
controller.close();
return;
}
if (shellChunkStatus !== ShellChunkStatus.FINISH) {
const chunk = new TextDecoder().decode(value);

chunkVec.push(chunk);

let concatedChunk = chunkVec.join('');
if (concatedChunk.includes(ESCAPED_SHELL_STREAM_END_MARK)) {
concatedChunk = concatedChunk.replace(
ESCAPED_SHELL_STREAM_END_MARK,
'',
);

shellChunkStatus = ShellChunkStatus.FINISH;

controller.enqueue(
encodeForWebStream(
`${shellBefore}${concatedChunk}${shellAfter}`,
),
);
// Flush any pending <script> collected before shell finished
if (pendingScripts.length > 0) {
for (const s of pendingScripts) {
controller.enqueue(encodeForWebStream(s));
}
pendingScripts.length = 0;
try {
const { done, value } = await reader.read();
if (done) {
closeController();
return;
}

if (isClosed) return;

if (shellChunkStatus !== ShellChunkStatus.FINISH) {
chunkVec.push(new TextDecoder().decode(value));
const concatedChunk = chunkVec.join('');

if (concatedChunk.includes(ESCAPED_SHELL_STREAM_END_MARK)) {
shellChunkStatus = ShellChunkStatus.FINISH;
safeEnqueue(
encodeForWebStream(
`${shellBefore}${concatedChunk.replace(
ESCAPED_SHELL_STREAM_END_MARK,
'',
)}${shellAfter}`,
),
);
flushPendingScripts();
}
} else {
safeEnqueue(value);
}

if (!isClosed) push();
} catch (error) {
if (!isClosed) {
isClosed = true;
try {
controller.error(error);
} catch {
// Controller already closed
}
}
} else {
controller.enqueue(value);
}
push();
}
push();
},
cancel(reason) {
reader.cancel(reason).catch(() => {
// Ignore cancellation errors
});
},
});
return stream;
} catch (e) {
Expand Down