gleam-lang/gleam · error

archive entry

Error message

archive entry

What it means

`.expect("archive entry")` unwraps each individual entry Result while iterating the decoded tar archive. It panics when a specific entry's header cannot be read from the stream — i.e. the archive is truncated or an entry record is malformed, even though the overall entries() iteration started fine.

Solutions

1. Surface the real error: replace expect with a panic that includes the entry error.
2. Validate the generated archive with `tar -tvzf` to find the malformed entry.
3. Check that each OutputFile's content length matches what the tar builder was given (header size vs written bytes).
4. Diff against a known-good archive produced before your change to isolate the regression.

Example fix

// before
let entry = entry.expect("archive entry");
// after
let entry = entry.unwrap_or_else(|e| panic!("archive entry: {e}"));

// Validate the whole archive once and report per-entry errors
let entries: Result<Vec<_>, _> = archive.entries().and_then(|it| it.collect());
let entries = entries.unwrap_or_else(|e| panic!("bad archive: {e}"));

let entry = entry.unwrap_or_else(|e| panic!("archive entry: {e}"));

When it happens

Trigger: Reading entry-by-entry in `create_tar_archive_sets_proper_permissions`: a malformed or truncated entry record in the generated archive makes `entry` an Err and the expect panics (compiler-cli/src/fs/tests.rs:281).

Common situations: Happens when the writer produces structurally broken tar records (e.g. entry data length mismatch) or the decode buffer is cut short; usually only seen after changing archive-writing code.

Related errors

• archive entries
• 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/1efc7ca79bb16bf4. Report an issue: GitHub.

Appendix: source

Thrown at compiler-cli/src/fs/tests.rs:281

#[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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