affaan-m/ECC · error · anyhow::Error

{stderr}

Error message

{stderr}

What it means

Same validation site as the generic invalid-ref error: when `validate_branch_name`'s underlying git check fails but git DOES print a message, the library bails with that raw `{stderr}`. So this error carries git's actual explanation, e.g. 'fatal: 'a..b' is not a valid branch name'.

Solutions

1. Read the stderr in the error message — it names the exact rule violated
2. Strip 'refs/heads/' or remote prefixes before validating ('name.rsplit_once("/")' is not enough; use the last segment)
3. Remove invalid sequences like '..' and '@{' and re-validate
4. Follow up with 'git check-ref-format' locally to confirm the sanitized name passes

Example fix

// before
let name = "feature/a..b";
validate_branch_name(&root, name)?;
// after
let name = name.trim_start_matches("refs/heads/").replace("..", "-");
validate_branch_name(&root, &name)?;

let check = Command::new("git")
    .args(["check-ref-format", "--branch", name])
    .output()?;
if !check.status.success() {
    let msg = String::from_utf8_lossy(&check.stderr).trim().to_string();
    anyhow::bail!("invalid branch name: {msg}");
}

fn is_valid_git_ref(name: &str) -> bool {
    !name.trim_start_matches("refs/heads/").is_empty()
        && !name.contains("..")
        && !name.contains("@{")
        && !name.starts_with('/')
        && !name.ends_with('/')
        && !name.contains(" ")
}

match validate_branch_name(&root, name) {
    Ok(()) => (),
    Err(e) => {
        // error body is git's own stderr — surface it verbatim to the user
        eprintln!("git rejected branch name: {e}");
        return Err(e);
    }
}

When it happens

Trigger: Calling branch creation/validation with a name git explicitly rejects, where stderr is non-empty: forbidden sequences ('..'), leading/trailing slashes, 'refs/heads/' prefixes, reserved names.

Common situations: Names pasted with 'origin/' or 'refs/heads/' prefixes; branch names containing '..' from version-range strings; unicode or emoji names on filesystems that reject them.

Understand the failure class

Background: "invalid id" errors: invalid identifier format — why libraries reject IDs before lookup, and how to fix them — this error's family across 37 libraries.

Related errors

• branch name is not a valid git ref
• commit message cannot be empty
• worktree_branch_prefix cannot be empty
• -32602
• a claim token is required

AI-assisted analysis of affaan-m/ECC@8321021c54 (2026-09-16). Data as JSON: /api/errors/1803808d7b43da04. Report an issue: GitHub.

Appendix: source

Thrown at ecc2/src/worktree/mod.rs:1493

    Ok(String::from_utf8_lossy(&output.stdout).trim().to_string())
}

fn validate_branch_name(repo_root: &Path, branch: &str) -> Result<()> {
    let output = Command::new("git")
        .arg("-C")
        .arg(repo_root)
        .args(["check-ref-format", "--branch", branch])
        .output()
        .context("Failed to validate worktree branch name")?;

    if output.status.success() {
        Ok(())
    } else {
        let stderr = String::from_utf8_lossy(&output.stderr).trim().to_string();
        if stderr.is_empty() {
            anyhow::bail!("branch name is not a valid git ref");
        } else {
            anyhow::bail!("{stderr}");
        }
    }
}

fn parse_git_status_entry(line: &str) -> Option<GitStatusEntry> {
    if line.len() < 4 {
        return None;
    }
    let bytes = line.as_bytes();
    let index_status = bytes[0] as char;
    let worktree_status = bytes[1] as char;
    let raw_path = line.get(3..)?.trim();
    if raw_path.is_empty() {
        return None;
    }
    let display_path = raw_path.to_string();
    let normalized_path = raw_path
        .split(" -> ")

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