From ed8363c88f445dbd22b738d8be11d9485b404b01 Mon Sep 17 00:00:00 2001
From: Rinat Khaziev <rinat.khaziev@gmail.com>
Date: Mon, 22 Jun 2026 19:56:28 -0500
Subject: [PATCH] Fix fetch failed due to unsupported expect header

---
 __tests__/lib/client-file-uploader.js | 64 +++++++++++++++++++++++++++
 src/lib/client-file-uploader.ts       | 25 ++++++++++-
 2 files changed, 88 insertions(+), 1 deletion(-)

diff --git a/__tests__/lib/client-file-uploader.js b/__tests__/lib/client-file-uploader.js
index 76e149dab..938455353 100644
--- a/__tests__/lib/client-file-uploader.js
+++ b/__tests__/lib/client-file-uploader.js
@@ -15,6 +15,7 @@ import {
 	getFileMeta,
 	getPartBoundaries,
 	parseEtagHeader,
+	uploadImportFileToS3,
 	uploadParts,
 } from '../../src/lib/client-file-uploader';
 
@@ -332,4 +333,67 @@ describe( 'client-file-uploader', () => {
 			expect( progress[ progress.length - 1 ] ).toBe( '100%' );
 		}, 15000 );
 	} );
+
+	describe( 'uploadImportFileToS3()', () => {
+		let tmpDir;
+
+		const uploadOkResponse = {
+			status: 200,
+			text: async () => '',
+		};
+
+		const writeTempFile = ( name, contents ) => {
+			const fileName = path.join( tmpDir, name );
+			writeFileSync( fileName, contents );
+			return fileName;
+		};
+
+		beforeAll( () => {
+			tmpDir = mkdtempSync( path.join( os.tmpdir(), 'vip-cli-upload-import-' ) );
+		} );
+
+		afterAll( () => {
+			rmSync( tmpDir, { recursive: true, force: true } );
+		} );
+
+		beforeEach( () => {
+			fetch.mockReset();
+			http.mockReset();
+		} );
+
+		it( 'should strip unsupported Expect headers from presigned PutObject uploads', async () => {
+			const fileName = writeTempFile( 'small-deploy.zip', 'zip contents' );
+			const fileMeta = {
+				...( await getFileMeta( fileName ) ),
+				fileContent: Buffer.from( 'zip contents' ),
+			};
+
+			http.mockResolvedValue( {
+				status: 200,
+				json: async () => ( {
+					url: 'https://s3.example.com/upload',
+					options: {
+						method: 'PUT',
+						headers: {
+							Expect: '100-continue',
+							'x-amz-server-side-encryption': 'AES256',
+						},
+					},
+				} ),
+			} );
+			fetch.mockResolvedValue( uploadOkResponse );
+
+			await uploadImportFileToS3( {
+				app: { id: 1 },
+				env: { id: 2 },
+				fileMeta,
+			} );
+
+			expect( fetch ).toHaveBeenCalledTimes( 1 );
+			expect( fetch.mock.calls[ 0 ][ 1 ].headers ).toEqual( {
+				'Content-Length': `${ fileMeta.fileSize }`,
+				'x-amz-server-side-encryption': 'AES256',
+			} );
+		} );
+	} );
 } );
diff --git a/src/lib/client-file-uploader.ts b/src/lib/client-file-uploader.ts
index abda49cbd..c9e6bca04 100644
--- a/src/lib/client-file-uploader.ts
+++ b/src/lib/client-file-uploader.ts
@@ -9,7 +9,7 @@ import { setTimeout } from 'node:timers/promises';
 import os from 'os';
 import path from 'path';
 import { PassThrough } from 'stream';
-import { fetch, type HeadersInit, type RequestInit, type Response } from 'undici';
+import { fetch, Headers, type HeadersInit, type RequestInit, type Response } from 'undici';
 import { Parser as XmlParser } from 'xml2js';
 import { createGunzip, createGzip, Gunzip, ZlibOptions } from 'zlib';
 
@@ -39,6 +39,28 @@ type RequestInitWithDuplex = RequestInit & { duplex?: 'half' };
 const isStreamBody = ( body: RequestInit[ 'body' ] ): boolean =>
 	typeof ( body as { pipe?: unknown } | null | undefined )?.pipe === 'function';
 
+const stripUndiciUnsupportedHeaders = ( headers?: HeadersInit ): HeadersInit | undefined => {
+	if ( ! headers ) {
+		return headers;
+	}
+
+	const isSupportedHeader = ( name: string ) => name.toLowerCase() !== 'expect';
+
+	if ( headers instanceof Headers ) {
+		const sanitized = new Headers( headers );
+		sanitized.delete( 'expect' );
+		return sanitized;
+	}
+
+	if ( Array.isArray( headers ) ) {
+		return headers.filter( ( [ name ] ) => isSupportedHeader( name ) );
+	}
+
+	return Object.fromEntries(
+		Object.entries( headers ).filter( ( [ name ] ) => isSupportedHeader( name ) )
+	);
+};
+
 /**
  * Wraps `fetch` with exponential-backoff retries.
  *
@@ -67,6 +89,7 @@ export async function fetchWithRetry(
 		const requestInit: RequestInitWithDuplex = createBody
 			? { ...init, body: createBody() }
 			: { ...init };
+		requestInit.headers = stripUndiciUnsupportedHeaders( requestInit.headers );
 		if ( isStreamBody( requestInit.body ) && ! requestInit.duplex ) {
 			requestInit.duplex = 'half';
 		}