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MLE-32051 Fix multipart body termination for Node.js v26 compatibility #1116

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Merged
rjdew-progress merged 5 commits into from
Aug 27, 2026
Merged

MLE-32051 Fix multipart body termination for Node.js v26 compatibility #1116

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f76f893
MLE-32051 Fix multipart body termination for Node.js v26 compatibility
jonmille Aug 24, 2026
4b3c604
MLE-32051 lint fixes
jonmille Aug 24, 2026
78a8678
MLE-32051 Copilot Suggestion Fixes
jonmille Aug 24, 2026
d3c2b68
MLE-32051 Jenkins test fixes
jonmille Aug 25, 2026
4d5d724
MLE-32051 Test fixes for test-basic/bindingFromParam.js
jonmille Aug 26, 2026
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125 changes: 88 additions & 37 deletions lib/requester.js
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@RitaChen609 RitaChen609 Aug 25, 2026

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Can you add repro tests to the test suite in the repo?

@RitaChen609 RitaChen609 Aug 26, 2026

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We don't need specific repro tests for this because the existing tests (test-basic/bindingFromParam.js, test-basic/optic-cts-param-test.js, etc) reproduce the same bug.

Original file line number Diff line number Diff line change
Expand Up @@ -420,11 +420,14 @@ function multipartRequester(request) {
const operation = this;

const operationBoundary = operation.multipartBoundary;
const multipartStream = new Multipart((operationBoundary == null) ?
mlutil.multipartBoundary : operationBoundary);
const boundary = (operationBoundary == null) ? mlutil.multipartBoundary : operationBoundary;
const CRNL = '\r\n';

const requestPartsProvider = operation.requestPartsProvider;
if(operation.bindingParam) {
if (operation.bindingParam) {
// bindingParam path: write boundary+headers as Buffers, pipe form-data stream directly.
// multipart-stream's addPart() writes headers synchronously to a PassThrough before piping,
// triggering the same Node.js v26+ 'readable' regression as the requestPartList path.
const form = new formData();
const bindingParam = operation.bindingParam;
const query = bindingParam.query;
Expand Down Expand Up @@ -468,41 +471,79 @@ function multipartRequester(request) {
form.append('metadata', JSON.stringify(metadata), {contentType: 'application/json', filename: 'metadata.json'});
}

multipartStream.add({
headers: {
'Content-Type': 'multipart/form-data; boundary=' + mlutil.multipartBoundary,
Accept: 'application/json',
},
body: form,
});
// All bindingParam content (query AST, binding, attachments, metadata) is synchronous
// JSON so getBuffer() collects it without streaming, avoiding the Node.js v26+
// sandwich-stream 'readable' regression entirely.
const formBuffer = form.getBuffer();
request.write(Buffer.from('--' + boundary + CRNL));
request.write(Buffer.from('Content-Type: multipart/form-data; boundary=' + mlutil.multipartBoundary + CRNL));
request.write(Buffer.from('Accept: application/json' + CRNL));
request.write(Buffer.from(CRNL));
request.write(formBuffer);
request.write(Buffer.from(CRNL + '--' + boundary + '--'));
request.end();
} else if (typeof requestPartsProvider === 'function') {
// requestPartsProvider path: use multipart-stream (provider controls parts)
const multipartStream = new Multipart(boundary);
requestPartsProvider.call(operation, multipartStream);
multipartStream.on('error', err => request.destroy(err));
multipartStream.pipe(request);
} else {
const parts = operation.requestPartList;
if (Array.isArray(parts)) {
const partsLen = parts.length;
operation.logger.debug('writing %s parts', partsLen);
for (let i=0; i < partsLen; i++) {
// Stream-driven PassThroughs receive writes asynchronously (after listeners are
// attached), so multipart-stream works correctly for them on all Node.js versions.
// Only the all-synchronous case triggers the Node.js v26+ 'readable' regression.
const hasStreamContent = Array.isArray(parts) &&
parts.some(p => p.content !== null && typeof p.content.pipe === 'function');

if (hasStreamContent) {
const multipartStream = new Multipart(boundary);
operation.logger.debug('writing %s parts', parts.length);
for (let i = 0; i < parts.length; i++) {
const part = parts[i];
const headers = part.headers;
const content = part.content;
if ((headers != null) &&
(content != null)) {
if ((headers !== null) && (content !== null)) {
operation.logger.debug('starting part %s', i);
multipartStream.addPart({
headers: headers,
body: content
});
multipartStream.addPart({ headers: headers, body: content });
operation.logger.debug('finished part %s', i);
} else {
operation.logger.debug('nothing to write for part %d', i);
}
}
multipartStream.on('error', err => request.destroy(err));
multipartStream.pipe(request);
} else {
operation.logger.debug('no part list to write');
// All synchronous content: build body directly as Buffers to avoid
// sandwich-stream's 'readable' event regression on Node.js v26+.
const bufs = [Buffer.from('--' + boundary + CRNL)];
let written = 0;
if (Array.isArray(parts)) {
operation.logger.debug('writing %s parts', parts.length);
for (let i = 0; i < parts.length; i++) {
const part = parts[i];
const headers = part.headers;
const content = part.content;
if ((headers != null) && (content != null)) {
if (written > 0) { bufs.push(Buffer.from(CRNL + '--' + boundary + CRNL)); }
operation.logger.debug('starting part %s', i);
Object.entries(headers).forEach(([k, v]) => bufs.push(Buffer.from(k + ': ' + v + CRNL)));
bufs.push(Buffer.from(CRNL));
bufs.push(Buffer.isBuffer(content) ? content : Buffer.from(content));
operation.logger.debug('finished part %s', i);
written++;
} else {
operation.logger.debug('nothing to write for part %d', i);
}
}
} else {
operation.logger.debug('no part list to write');
}
bufs.push(Buffer.from(CRNL + '--' + boundary + '--'));
for (let i = 0; i < bufs.length - 1; i++) { request.write(bufs[i]); }
request.end(bufs[bufs.length - 1]);
}
}
multipartStream.pipe(request);
}
function chunkedRequester(request) {
/*jshint validthis:true */
Expand Down Expand Up @@ -530,38 +571,48 @@ function chunkedMultipartRequester(request) {
request.end();
} else {
const operationBoundary = operation.multipartBoundary;
const boundary = (operationBoundary == null) ? mlutil.multipartBoundary : operationBoundary;
const CRNL = '\r\n';

const multipartStream = new Multipart((operationBoundary == null) ?
mlutil.multipartBoundary : operationBoundary);

// Write all non-stream (metadata) parts directly as Buffers, then pipe the
// streaming content part into the request. This avoids the sandwich-stream
// 'readable' event regression on Node.js v26+ where multi-chunk PassThrough
// streams are not fully drained, leaving the closing boundary unemitted.
const partLast = requestDocument.length - 1;
request.write(Buffer.from('--' + boundary + CRNL));
let written = 0;
for (let i=0; i <= partLast; i++) {
const part = requestDocument[i];
const headers = part.headers;
if (i < partLast) {
const content = part.content;
if ((headers != null) &&
(content != null)) {
multipartStream.addPart({
headers: headers,
body: mlutil.marshal(content, operation)
});
if ((headers != null) && (content != null)) {
if (written > 0) { request.write(Buffer.from(CRNL + '--' + boundary + CRNL)); }
Object.entries(headers).forEach(([k, v]) => request.write(Buffer.from(k + ': ' + v + CRNL)));
request.write(Buffer.from(CRNL));
const marshaledContent = mlutil.marshal(content, operation);
request.write(Buffer.isBuffer(marshaledContent) ? marshaledContent : Buffer.from(marshaledContent));
written++;
} else {
operation.logger.debug('could not write metadata part');
}
} else {
if (headers != null) {
multipartStream.addPart({
headers: headers,
body: requestWriter
});
if (written > 0) { request.write(Buffer.from(CRNL + '--' + boundary + CRNL)); }
Object.entries(headers).forEach(([k, v]) => request.write(Buffer.from(k + ': ' + v + CRNL)));
request.write(Buffer.from(CRNL));
requestWriter.on('error', err => request.destroy(err));
requestWriter.pipe(request, { end: false });
requestWriter.on('end', () => {
request.write(Buffer.from(CRNL + '--' + boundary + '--'));
request.end();
});
} else {
operation.logger.debug('could not write content part');
request.end();
}
}
}

multipartStream.pipe(request);
}
}

Expand Down
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