GitoxideLabs/gitoxide · error

Format for extension

Error message

Format for extension '{ext}' is unsupported

What it means

`format_from_ext` supports only the extensions tar, gz, zip, and stream. Any other extension causes a bail naming the unsupported extension. This is a whitelist of explicitly implemented archive formats.

Solutions

1. Rename the output to an exact supported extension: `.tar`, `.gz`, `.zip`, or `.stream`
2. Use `.tar.gz` -> not supported; instead write to `.gz` (TarGz) per the implementation
3. Add post-processing (e.g. pipe the tar output through zstd) outside of gix for other compressions
4. Check `archive::Format` for the currently supported set before choosing a filename

Example fix

// before
let out = Path::new("release.tgz");
// after
let out = Path::new("release.gz"); // TarGz

const SUPPORTED: &[&str] = &["tar", "gz", "zip", "stream"];
let ext = path.extension().and_then(|e| e.to_str()).unwrap_or("");
anyhow::ensure!(SUPPORTED.contains(&ext), "extension '{ext}' unsupported; use one of {SUPPORTED:?}");

match format_from_ext(path) {
    Err(e) if e.to_string().contains("is unsupported") => {
        eprintln!("use .tar, .gz, .zip or .stream");
    }
    other => other?,
}

When it happens

Trigger: Calling `archive::stream` with an output file whose extension is anything outside {tar, gz, zip, stream}, e.g. `out.tgz`, `out.tar.zst`, `out.bz2`, `out.rar`.

Common situations: Users typing `.tgz` or `.tar.gz` expecting gzip support; requesting zstd/bzip2 compression not yet implemented; scripts defaulting to `.7z`.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

• Cannot derive archive format from a file without extension
• lines in ' ' could not be parsed
• Invalid pathspec - path must not be empty, not be excluded…
• : Validation failed with mismatches out of
• path does not name a file

AI-assisted analysis of GitoxideLabs/gitoxide@e73179060b (2026-09-08). Data as JSON: /api/errors/a31a1589b01b140d. Report an issue: GitHub.

Appendix: source

Thrown at gitoxide-core/src/repository/archive.rs:106

        }
        gix::object::Kind::Tree => (None, object.id),
        gix::object::Kind::Tag => fetch_rev_info(object.peel_to_kind(gix::object::Kind::Commit)?)?,
        gix::object::Kind::Blob => bail!("Cannot derive commit or tree from blob at {}", object.id),
    })
}

fn format_from_ext(path: &Path) -> anyhow::Result<archive::Format> {
    Ok(match path.extension().and_then(std::ffi::OsStr::to_str) {
        None => bail!("Cannot derive archive format from a file without extension"),
        Some("tar") => archive::Format::Tar,
        Some("gz") => archive::Format::TarGz {
            compression_level: None,
        },
        Some("zip") => archive::Format::Zip {
            compression_level: None,
        },
        Some("stream") => archive::Format::InternalTransientNonPersistable,
        Some(ext) => bail!("Format for extension '{ext}' is unsupported"),
    })
}

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