From f1c2d6ce4095a4003ab45a828122f07b172da656 Mon Sep 17 00:00:00 2001
From: Aditya Garud <153842990+yashranaway@users.noreply.github.com>
Date: Thu, 22 Oct 2026 07:36:29 +0000
Subject: [PATCH] fix(recorder-core): declare final Drive size at part
 boundaries

---
 .../instant-recording-uploader.test.ts        | 76 +++++++++++++++++++
 .../recorder-core/src/instant-mp4-uploader.ts |  9 ++-
 2 files changed, 84 insertions(+), 1 deletion(-)

diff --git a/packages/recorder-core/__tests__/instant-recording-uploader.test.ts b/packages/recorder-core/__tests__/instant-recording-uploader.test.ts
index 45334fa20da..b1255f39a91 100644
--- a/packages/recorder-core/__tests__/instant-recording-uploader.test.ts
+++ b/packages/recorder-core/__tests__/instant-recording-uploader.test.ts
@@ -466,6 +466,82 @@ describe("InstantRecordingUploader", () => {
 		);
 	});
 
+	it.each([
+		[DRIVE_PART_BYTES - 1, false],
+		[DRIVE_PART_BYTES, false],
+		[DRIVE_PART_BYTES, true],
+		[DRIVE_PART_BYTES + 1, false],
+		[2 * DRIVE_PART_BYTES, false],
+		[2 * DRIVE_PART_BYTES, true],
+	] as const)(
+		"declares the final Drive size for %i streamed bytes, final Blob: %s",
+		async (totalBytes, withFinalBlob) => {
+			const partCount = Math.ceil(totalBytes / DRIVE_PART_BYTES);
+			const fetchMock = vi.fn(
+				async (input: RequestInfo | URL, init?: RequestInit) => {
+					if (input.toString().endsWith("/presign-part")) {
+						return makeJsonResponse({
+							presignedUrl:
+								"https://www.googleapis.com/upload/drive/v3/files/session",
+							provider: "googleDrive",
+						});
+					}
+					expect(input.toString()).toBe("/api/upload/multipart/complete");
+					const body = JSON.parse(String(init?.body));
+					expect(body.parts).toEqual(
+						Array.from({ length: partCount }, (_, index) => ({
+							partNumber: index + 1,
+							etag: `drive-${index + 1}`,
+							size: Math.min(
+								DRIVE_PART_BYTES,
+								totalBytes - index * DRIVE_PART_BYTES,
+							),
+						})),
+					);
+					return makeJsonResponse({ success: true });
+				},
+			);
+			vi.stubGlobal("fetch", fetchMock);
+			MockXMLHttpRequest.setOutcomes(
+				Array.from({ length: partCount }, (_, index) => ({
+					type: "success",
+					status: index === partCount - 1 ? 200 : 308,
+				})),
+			);
+			const uploader = new InstantRecordingUploader({
+				videoId,
+				uploadId: "drive-session",
+				provider: "googleDrive",
+				mimeType: "video/webm",
+				subpath: "raw-upload.webm",
+				setUploadStatus: vi.fn(),
+				sendProgressUpdate: vi.fn().mockResolvedValue(undefined),
+			});
+			const blob = makeBlob(totalBytes, "video/webm");
+			uploader.handleChunk(blob, totalBytes);
+			await new Promise<void>((resolve) => setImmediate(resolve));
+
+			const streamedPartCount = MockXMLHttpRequest.recordedParts.length;
+			await uploader.finalize({
+				finalBlob: withFinalBlob ? blob : undefined,
+				durationSeconds: 20,
+				subpath: "raw-upload.webm",
+			});
+
+			expect(
+				MockXMLHttpRequest.recordedHeaders.map((headers) =>
+					headers.get("content-range"),
+				),
+			).toEqual(
+				Array.from({ length: partCount }, (_, index) => {
+					const end = Math.min((index + 1) * DRIVE_PART_BYTES, totalBytes);
+					return `bytes ${index * DRIVE_PART_BYTES}-${end - 1}/${end === totalBytes ? totalBytes : "*"}`;
+				}),
+			);
+			expect(streamedPartCount).toBe(partCount - 1);
+		},
+	);
+
 	it("completes multipart uploads with parts ordered by part number", async () => {
 		const fetchMock = vi.fn(
 			async (input: RequestInfo | URL, init?: RequestInit) => {
diff --git a/packages/recorder-core/src/instant-mp4-uploader.ts b/packages/recorder-core/src/instant-mp4-uploader.ts
index 11f33a33a68..164a219b97e 100644
--- a/packages/recorder-core/src/instant-mp4-uploader.ts
+++ b/packages/recorder-core/src/instant-mp4-uploader.ts
@@ -505,7 +505,14 @@ export class InstantRecordingUploader {
 				? DRIVE_PART_SIZE_BYTES
 				: MIN_PART_SIZE_BYTES;
 		while (this.bufferedBytes > 0) {
-			if (!force && this.bufferedBytes < targetPartSize) return;
+			if (
+				!force &&
+				(this.bufferedBytes < targetPartSize ||
+					(this.provider === "googleDrive" &&
+						this.bufferedBytes === targetPartSize))
+			) {
+				return;
+			}
 
 			const partSize = Math.min(this.bufferedBytes, targetPartSize);
 			const { part, remainingChunks, remainingBytes } =