xai-org/grok-build · error

'{}' is not a valid revision: {}

Error message

'{}' is not a valid revision: {}

What it means

For GitRef::Treeish, read_version_bytes resolves the refspec with git2's revparse_single. If the string is not a valid revision (unknown branch/tag/SHA or malformed syntax), this error is thrown. It validates the user- or session-supplied version identifier before any content is read.

Source

Thrown at crates/codegen/xai-grok-workspace/src/session/git.rs:768

        };
        diff_compare(repo, base_ref, head_ref, merge_base, opts)
    }
}
fn read_version_bytes(repo: &Repository, path: &str, version: &str) -> Result<Vec<u8>> {
    match GitRef::parse(version) {
        GitRef::Workdir => {
            let full_path = repo
                .workdir()
                .ok_or_else(|| anyhow::anyhow!("cannot read working files from bare repository"))?
                .join(path);
            std::fs::read(&full_path)
                .map_err(|e| anyhow::anyhow!("failed to read '{}': {}", path, e))
        }
        GitRef::Index => read_blob_from_index(repo, path),
        GitRef::Treeish(refspec) => {
            let obj = repo
                .revparse_single(&refspec)
                .map_err(|e| anyhow::anyhow!("'{}' is not a valid revision: {}", refspec, e))?;
            let commit = obj
                .peel_to_commit()
                .map_err(|e| anyhow::anyhow!("'{}' does not refer to a commit: {}", refspec, e))?;
            let tree = commit.tree()?;
            read_blob_from_tree(repo, &tree, path)
        }
    }
}
/// Binary files return empty content with is_binary=true.
fn read_version_content(repo: &Repository, path: &str, version: &str) -> Result<(String, bool)> {
    let bytes = read_version_bytes(repo, path, version)?;
    match String::from_utf8(bytes) {
        Ok(text) => Ok((text, false)),
        Err(_) => Ok((String::new(), true)),
    }
}
fn read_version_text(repo: &Repository, path: &str, version: &str) -> Option<String> {
    read_version_content(repo, path, version)

View on GitHub (pinned to bc7f02eddd)

Solutions

  1. Validate the ref with `git rev-parse --verify <refspec>` before reading
  2. Use a full commit SHA instead of a branch name so history stays stable after branch deletion
  3. Check `git branch -a` / `git tag -l` for the correct name; fetch if the object is missing (`git fetch --all`)
  4. Handle the error by listing available versions instead of propagating a raw failure

Example fix

// before
let bytes = read_version_bytes(&repo, "src/main.rs", "feature-x")?; // branch deleted
// after
let bytes = match read_version_bytes(&repo, "src/main.rs", "feature-x") {
    Ok(b) => b,
    Err(e) if e.to_string().contains("is not a valid revision") => {
        read_version_bytes(&repo, "src/main.rs", "HEAD")? // stable fallback
    }
    Err(e) => return Err(e),
};
Defensive patterns

Strategy: validation

Validate before calling

fn revision_exists(repo: &git2::Repository, refspec: &str) -> bool {
    repo.revparse_single(refspec).is_ok()
}
if !revision_exists(&repo, version) {
    anyhow::bail!("unknown revision: {}", version);
}

Try / catch

match read_version_bytes(repo, path, version) {
    Ok(b) => b,
    Err(e) if e.to_string().contains("is not a valid revision") => {
        read_version_bytes(repo, path, "HEAD")? // stable fallback
    }
    Err(e) => return Err(e),
}

Prevention

When it happens

Trigger: Calling read_version_content with a treeish version string that does not resolve: deleted branch, typo'd SHA, nonexistent tag, or invalid syntax like an empty or dangling refspec.

Common situations: Session history referencing a branch that was later deleted, truncated SHAs that no longer resolve after garbage collection, tags removed on the remote, or versions stored with wrong format.

Related errors

AI-assisted analysis of xai-org/grok-build@bc7f02eddd (2026-08-31). Data as JSON: /api/errors/b7e7549a36d6d560. Report an issue: GitHub.