diem/diem · error · anyhow::Error

No initial command

Error message

No initial command

What it means

taskify buckets consecutive non-empty lines of a test file into tasks; a bucket that produced no commands at the very first position means the file starts with a blank/empty command bucket. The harness bails because a task stream must begin with at least one command to attach directives to.

Source

Thrown at language/testing-infra/transactional-test-runner/src/tasks.rs:90

        } else if WHITESPACE.is_match(&line) {
            in_command = false;
            continue;
        } else {
            in_command = false;
            cur_text.push((line_number, line))
        }
    }
    bucketed_lines.push((cur_commands, cur_text));

    if bucketed_lines.is_empty() {
        return Ok(vec![]);
    }

    let mut tasks = vec![];
    for (number, (commands, text)) in bucketed_lines.into_iter().enumerate() {
        if commands.is_empty() {
            assert!(number == 0);
            bail!("No initial command")
        }

        let start_line = commands.first().unwrap().0;
        let command_lines_stop = commands.last().unwrap().0;
        let mut command_text = "task ".to_string();
        for (line_number, text) in commands {
            assert!(!text.is_empty(), "{}: {}", line_number, text);
            command_text = format!("{} {}", command_text, text);
        }
        let command_split = command_text.split_ascii_whitespace().collect::<Vec<_>>();
        let name_opt = command_split.get(1).map(|s| (*s).to_owned());
        let command = match Command::from_iter_safe(command_split) {
            Ok(command) => command,
            Err(e) => {
                let mut spit_iter = command_text.split_ascii_whitespace();
                // skip 'task'
                spit_iter.next();
                let help_command = match spit_iter.next() {

View on GitHub (pinned to fc4714a8ea)

Solutions

1. Ensure the test file starts with a valid command directive (e.g. '//# run ...' or '// options ...') and no leading empty bucket
2. Remove stray blank/comment-only lines at the top of the file so the first bucket contains a command
3. Verify you passed the correct file path to the test runner

Example fix

// before


//# run 0x1::m::f
// after (command on the first bucket)
//# run 0x1::m::f

// Before calling taskify, check the file starts with a command bucket
let first_bucket_has_command = lines.iter()
    .find(|l| !l.trim().is_empty())
    .map_or(false, |l| l.trim_start().starts_with("//#"));
assert!(first_bucket_has_command, "test file must begin with a //# command directive");

match taskify(text) {
    Err(e) if e.to_string() == "No initial command" => {
        bail!("Test file is empty or starts without a command directive; add e.g. '//# run ...' at the top")
    }
    other => other,
}

When it happens

Trigger: Running taskify on a .move test file whose first bucketed line group contains no parseable commands (empty file, or the first bucket is empty) — the assert!(number == 0) confirms this only fires for the first bucket.

Common situations: A test file that begins with blank lines or only comments so the first bucket has zero commands; malformed directive syntax at the top of the file that parses to no commands; accidentally passing an empty or wrong file to taskify.

Related errors

• Invalid command. Got error {} Lines {} - {}. {}
• Failed to parse address. Got error: {}
• Invalid module access. Did not expect type arguments
• Error: could not find an available port
• fail to set actions for failpoint

AI-assisted analysis of diem/diem@fc4714a8ea (2026-09-04). Data as JSON: /api/errors/198d3b94a187cd3a. Report an issue: GitHub.