fix(ZipFS): support empty archives resulting from an unlink after write in getBufferAndClose

.yarn/versions/1f698bb0.yml

@@ -0,0 +1,12 @@
+releases:
+  "@yarnpkg/libzip": patch
+
+declined:
+  - "@yarnpkg/plugin-file"
+  - "@yarnpkg/plugin-nm"
+  - "@yarnpkg/plugin-patch"
+  - vscode-zipfs
+  - "@yarnpkg/cli"
+  - "@yarnpkg/core"
+  - "@yarnpkg/fslib"
+  - "@yarnpkg/pnp"

CHANGELOG.md

@@ -71,6 +71,7 @@ The following changes only affect people writing Yarn plugins:
 
 - `yarn dlx` will no longer report false-positive `UNUSED_PACKAGE_EXTENSION` warnings
 - `yarn workspace` will now set `$INIT_CWD` to the CLI working directory rather than the workspace root.
+- `ZipFS.prototype.getBufferAndClose` will not error on empty archives resulting from an unlink after write.
 
 ### Shell
 

packages/yarnpkg-libzip/sources/ZipFS.ts

@@ -247,6 +247,12 @@ export class ZipFS extends BasePortableFakeFS {
     if (!this.lzSource)
       throw new Error(`ZipFS was not created from a Buffer`);
 
+    // zip_source_open on an unlink-after-write empty archive fails with "Entry has been deleted"
+    if (this.entries.size === 0) {
+      this.discardAndClose();
+      return makeEmptyArchive();
+    }
+
     try {
       // Prevent close from cleaning up the source
       this.libzip.source.keep(this.lzSource);

packages/yarnpkg-libzip/tests/ZipFS.test.ts

@@ -678,6 +678,19 @@ describe(`ZipFS`, () => {
     expect(new ZipFS(buffer).readdirSync(PortablePath.root)).toHaveLength(0);
   });
 
+  it(`should support getting the buffer from an empty in-memory zip archive (unlink after write)`, () => {
+    const zipFs = new ZipFS();
+
+    zipFs.writeFileSync(`/foo.txt` as PortablePath, `foo`);
+    zipFs.unlinkSync(`/foo.txt` as PortablePath);
+
+    const buffer = zipFs.getBufferAndClose();
+
+    expect(buffer).toStrictEqual(makeEmptyArchive());
+
+    expect(new ZipFS(buffer).readdirSync(PortablePath.root)).toHaveLength(0);
+  });
+
   ifNotWin32It(`should preserve the umask`, async () => {
     const tmpdir = xfs.mktempSync();
     const archive = `${tmpdir}/archive.zip` as PortablePath;