gitbutlerapp/gitbutler · error

failed to discover GitButler branch with 'but --json status'

Error message

failed to discover GitButler branch with 'but --json status': {stderr}

What it means

When `but agentlog skim` runs with no explicit target, it re-executes itself as `but --json status` in the workdir (current_exe -C <dir> --json status) to find the first applied GitButler branch. If that subprocess exits non-zero, this error embeds its stderr — typical causes are the workdir not being a GitButler workspace, no target/base branch configured, or an older binary without --json status support.

Source

Thrown at crates/but-agentlog/src/skim.rs:355

}

#[derive(Deserialize)]
struct StatusBranch {
    name: String,
}

fn applied_gitbutler_branch(workdir: &Path) -> anyhow::Result<String> {
    let but_path = std::env::current_exe().context("failed to locate current executable")?;
    let output = ProcessCommand::new(&but_path)
        .arg("-C")
        .arg(workdir)
        .args(["--json", "status"])
        .stdin(Stdio::null())
        .output()
        .context("failed to run 'but --json status' for agentlog skim target discovery")?;
    if !output.status.success() {
        let stderr = String::from_utf8_lossy(&output.stderr);
        anyhow::bail!("failed to discover GitButler branch with 'but --json status': {stderr}");
    }
    let status: StatusReport =
        serde_json::from_slice(&output.stdout).context("failed to parse 'but --json status'")?;
    status
        .stacks
        .into_iter()
        .flat_map(|stack| stack.branches)
        .map(|branch| branch.name)
        .next()
        .context("no applied GitButler branch found; pass an explicit skim target")
}

View on GitHub (pinned to 2497b8007a)

Solutions

1. Pass an explicit target so discovery is skipped: but agentlog skim branch <name>.
2. Run `but --json status` manually in the same directory and fix whatever it reports (set a target branch, reopen the workspace).
3. Ensure the executing binary (std::env::current_exe) is a recent but/tauri build that supports --json status.
4. Verify the workdir is inside the GitButler project you intended.

Example fix

# before
but agentlog skim
# after (skip auto-discovery)
but agentlog skim branch feat/auth

use std::process::Command as Pc;

fn skim_discovery_will_succeed(dir: &std::path::Path) -> bool {
    Pc::new(std::env::current_exe().unwrap())
        .arg("-C").arg(dir)
        .args(["--json", "status"])
        .output()
        .map(|o| o.status.success())
        .unwrap_or(false)
}

match skim::resolve_default_branch_target(&repo_path) {
    Err(_) => skim_with_explicit_branch("main"), // skip auto-discovery entirely
    ok => ok?,
}

When it happens

Trigger: skim::resolve_default_branch_target -> applied_gitbutler_branch: the spawned `but --json status` fails. Happens when -C <dir> is outside any GitButler-managed repo, the project has no target branch or applied stacks, status itself errors (auth, corrupt repo), or current_exe is an old build.

Common situations: Running skim in a plain git clone; pointing --dir at the wrong folder; PATH resolution landing on a stale but binary; workspaces discarded from the project.

Related errors

• {} target value is required
• target kind is required when target value is provided
• unknown publish target '{other}'. Use `but agentlog publish

AI-assisted analysis of gitbutlerapp/gitbutler@2497b8007a (2026-08-17). Data as JSON: /api/errors/53f8b73a85a59d00. Report an issue: GitHub.