gleam-lang/gleam · error

archive entries

Error message

archive entries

What it means

`.expect("archive entries")` wraps `archive.entries()` when reading back the generated tarball with flate2's GzDecoder. It panics if iterating the archive fails — typically because the compressed bytes are corrupt or not a valid gzipped tar, or an entry header cannot be read.

Solutions

1. Verify the archive is gzip-compressed: `file archive.tar.gz` / feed bytes to `tar -tzf`.
2. Confirm GzDecoder is the right reader for what create_tar_archive writes (flate2 GzEncoder output).
3. Print the underlying error: replace expect with `unwrap_or_else(|e| panic!("archive entries: {e}"))`.
4. Regenerate/inspect the archive bytes with an external tool to spot corruption.

Example fix

// before
for entry in archive.entries().expect("archive entries") {
// after
for entry in archive.entries().unwrap_or_else(|e| panic!("archive entries: {e}")) {

// Quick sanity check that the bytes are gzip
assert_eq!(&compressed_archive[..2], &[0x1f, 0x8b], "not gzip data");

for entry in archive.entries().unwrap_or_else(|e| panic!("archive entries: {e}")) {
    ...
}

When it happens

Trigger: Decoding the produced archive in the test: if `create_tar_archive` produced malformed/corrupt gzip data, or the Cursor contents were truncated/altered, `entries()` returns Err and the expect panics (compiler-cli/src/fs/tests.rs:280).

Common situations: Encountered when the archive writer is changed (e.g. wrong compression, writing raw tar without gzip) or when decode setup (decoder/reader wiring) is modified incorrectly.

Related errors

• archive entry
• should create archive
• Non Utf-8 Path
• bytes must not be empty
• case with no subjects

AI-assisted analysis of gleam-lang/gleam@15b07c7830 (2026-09-14). Data as JSON: /api/errors/e2d6021e053143d7. Report an issue: GitHub.

Appendix: source

Thrown at compiler-cli/src/fs/tests.rs:280

// https://github.com/gleam-lang/gleam/issues/5992
#[test]
fn create_tar_archive_sets_proper_permissions() {
    let compressed_archive = create_tar_archive(vec![
        OutputFile {
            content: Content::Text("Hello".into()),
            path: "./wibble.txt".into(),
        },
        OutputFile {
            content: Content::Binary(vec![11, 6, 7]),
            path: "./wobble.bin".into(),
        },
    ])
    .expect("should create archive");

    let decoder = flate2::read::GzDecoder::new(Cursor::new(compressed_archive));
    let mut archive = tar::Archive::new(decoder);

    for entry in archive.entries().expect("archive entries") {
        let entry = entry.expect("archive entry");
        let mode = entry.header().mode().expect("entry mode");
        let entry_path = entry.path().expect("entry path");
        let path_str = entry_path.to_str().expect("path string");
        assert_eq!(mode, 0o600, "entry {path_str} has unexpected mode")
    }
}

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