v8 archive {} did not contain a top-level `lib/` directory a

Error message

v8 archive {} did not contain a top-level `lib/` directory after unpack (expected {})

What it means

Error "v8 archive {} did not contain a top-level `lib/` directory after unpack (expected {})" thrown in wasmerio/wasmer.

Source

Thrown at lib/api/build.rs:125

            panic!(
                "failed to create temporary wee8 unpack directory in {}: {err}",
                cache_dir.display()
            )
        });
        let tar = xz::read::XzDecoder::new(tar_data.as_slice());
        let mut archive = tar::Archive::new(tar);
        archive.unpack(unpack_tmp.path()).unwrap_or_else(|err| {
            let _ = fs::remove_file(&archive_path);
            panic!(
                "failed to unpack v8 archive cache {} into {} (cache removed so the next build can re-download): {err}",
                archive_path.display(),
                unpack_tmp.path().display()
            )
        });
        let staged_lib = unpack_tmp.path().join("lib");
        if !staged_lib.is_dir() {
            let _ = fs::remove_file(&archive_path);
            panic!(
                "v8 archive {} did not contain a top-level `lib/` directory after unpack (expected {})",
                archive_path.display(),
                staged_lib.display()
            );
        }
        if v8_lib_dir.exists() {
            fs::remove_dir_all(&v8_lib_dir).unwrap_or_else(|err| {
                panic!(
                    "failed to remove existing wee8 lib dir {} before rename: {err}",
                    v8_lib_dir.display()
                )
            });
        }
        fs::rename(&staged_lib, &v8_lib_dir).unwrap_or_else(|err| {
            let _ = fs::remove_file(&archive_path);
            panic!(
                "failed to move unpacked wee8 lib from {} to {}: {err}",
                staged_lib.display(),

View on GitHub (pinned to 8c4b9ee9d3)

When it happens

Trigger: Thrown at lib/api/build.rs:125 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of wasmerio/wasmer@8c4b9ee9d3 (2026-09-01). Data as JSON: /api/errors/4bcb7c8f27ad2fc4. Report an issue: GitHub.