fix: zip symlinked files as their content and finish writing the zip before upload

src/lib/utils.ts

@@ -1,9 +1,18 @@
 import { execSync } from 'node:child_process';
-import { createWriteStream, existsSync, readdirSync, readFileSync, realpathSync, writeFileSync } from 'node:fs';
+import {
+	createWriteStream,
+	existsSync,
+	readdirSync,
+	readFileSync,
+	realpathSync,
+	statSync,
+	writeFileSync,
+} from 'node:fs';
 import { mkdir, readFile } from 'node:fs/promises';
 import { homedir } from 'node:os';
 import { dirname, join, relative, resolve, sep } from 'node:path';
 import process from 'node:process';
+import { finished } from 'node:stream/promises';
 
 import { DurationFormatter as SapphireDurationFormatter, TimeTypes } from '@sapphire/duration';
 import { Timestamp } from '@sapphire/timestamp';
@@ -573,9 +582,15 @@ export const createActZip = async (zipName: string, pathsToZip: string[], cwd: s
 	});
 	archive.pipe(writeStream);
 
-	pathsToZip.forEach((filePath) => archive.file(join(cwd, filePath), { name: filePath }));
+	pathsToZip.forEach((filePath) => {
+		const absolutePath = join(cwd, filePath);
+		// The platform unzips links as links; send a linked file as its content, as the multi-file upload does.
+		archive.file(absolutePath, { name: filePath, stats: statSync(absolutePath) });
+	});
 
 	await archive.finalize();
+	// The archive ends before the file stream has written all of it, and push reads the file right away.
+	await finished(writeStream);
 };
 
 export interface LocalInput {

test/local/lib/utils.test.ts

@@ -1,6 +1,8 @@
-import { existsSync, writeFileSync } from 'node:fs';
+import { existsSync, readFileSync, symlinkSync, writeFileSync } from 'node:fs';
 import { join } from 'node:path';
+import process from 'node:process';
 
+import AdmZip from 'adm-zip';
 import axios from 'axios';
 
 import { execWithLog } from '../../../src/lib/exec.js';
@@ -86,6 +88,31 @@ describe('Utils', () => {
 				expect(existsSync(join(tempFolder, file))).toBeFalsy(),
 			);
 		});
+
+		it('has the whole zip written when it resolves', async () => {
+			const zipName = joinPath('complete.zip');
+			await createActZip(zipName, FILES, tmpPath);
+
+			expect(
+				new AdmZip(readFileSync(zipName))
+					.getEntries()
+					.map((entry) => entry.entryName)
+					.sort(),
+			).toEqual([...FILES].sort());
+		});
+
+		// Creating a symlink on Windows needs extra rights.
+		it.skipIf(process.platform === 'win32')('zips a file reached through a symlink as its content', async () => {
+			// A link entry would hold the link's target path, which the platform unzips as a link to a file the upload
+			// may not hold.
+			const zipName = joinPath('linked.zip');
+			writeFileSync(joinPath('linked-target.json'), '{"title":"Input"}');
+			symlinkSync('linked-target.json', joinPath('linked.json'));
+
+			await createActZip(zipName, ['linked.json'], tmpPath);
+
+			expect(new AdmZip(readFileSync(zipName)).getEntry('linked.json')?.getData().toString()).toBe('{"title":"Input"}');
+		});
 	});
 
 	describe('downloadAndUnzip()', () => {