rust-lang/rust · error · anyhow::Error

It is only possible to schedule up to {MAX_TRY_JOBS_COUNT} c

Error message

It is only possible to schedule up to {MAX_TRY_JOBS_COUNT} custom jobs, received {} custom jobs expanded from {} pattern(s)

What it means

citool caps the number of jobs a single try build can schedule at MAX_TRY_JOBS_COUNT (= 20, jobs.rs:283). After expanding try-job patterns into concrete auto/optional jobs, if the resulting list length exceeds 20, the error reports both the expanded count and the number of input patterns.

Source

Thrown at src/ci/citool/src/jobs.rs:315

                    let matched_jobs = db.find_auto_or_optional_jobs_by_pattern(pattern);
                    if matched_jobs.is_empty() {
                        unknown_patterns.push(pattern.clone());
                    } else {
                        for job in matched_jobs {
                            if !jobs.iter().any(|j| j.name == job.name) {
                                jobs.push(job);
                            }
                        }
                    }
                }
                if !unknown_patterns.is_empty() {
                    return Err(anyhow::anyhow!(
                        "Patterns `{}` did not match any auto jobs",
                        unknown_patterns.join(", ")
                    ));
                }
                if jobs.len() > MAX_TRY_JOBS_COUNT {
                    return Err(anyhow::anyhow!(
                        "It is only possible to schedule up to {MAX_TRY_JOBS_COUNT} custom jobs, received {} custom jobs expanded from {} pattern(s)",
                        jobs.len(),
                        patterns.len()
                    ));
                }
                jobs
            } else {
                db.try_jobs.clone()
            };
            (jobs, "try", &db.envs.try_env)
        }
        RunType::AutoJob => (db.auto_jobs.clone(), "auto", &db.envs.auto_env),
        RunType::MainJob => return Ok(vec![]),
    };
    let jobs = substitute_github_vars(jobs.clone())
        .context("Failed to substitute GitHub context variables in jobs")?;
    let jobs = skip_jobs(jobs, channel);
    let jobs = jobs

View on GitHub (pinned to 7088e4b63a)

Solutions

Narrow the patterns so the expanded set stays within 20 jobs.
Split the try into multiple runs if you genuinely need more than 20 jobs.
Replace broad patterns with explicit job names you actually need.
Remove redundant patterns that expand to overlapping job sets.

Example fix

# before
@bors try dist-*   # expands to 30 jobs -> error

# after
@bors try dist-x86_64-unknown-linux-gnu dist-aarch64-unknown-linux-gnu

Defensive patterns

Strategy: validation

Validate before calling

const MAX_TRY_JOBS_COUNT: usize = 20;
fn within_quota(expanded: &[Job]) -> bool { expanded.len() <= MAX_TRY_JOBS_COUNT }
// After expanding patterns, assert within_quota(&jobs) before submitting the try build.

Prevention

Keep try-job pattern expansions under 20 jobs.
Use explicit job names instead of broad globs.
Split large try runs into multiple smaller ones.

When it happens

Trigger: Submitting @bors try with one or more patterns that match more than 20 distinct auto/optional jobs (e.g. a broad pattern like '*' or several prefixes that together cover >20 jobs).

Common situations: Using an overly-broad glob to rerun a large slice of CI; accumulating patterns that each match many jobs; trying to rerun the whole matrix.

Related errors

AI-assisted analysis of rust-lang/rust@7088e4b63a (2026-08-10). Data as JSON: /api/errors/4f4e5584a4508193. Report an issue: GitHub.