task {} cache requires explicit outputs or outputs = []

Error message

task {} cache requires explicit outputs or outputs = []

What it means

validate_config requires explicit outputs for cached tasks: task.outputs must not be in Auto mode (TaskOutputs::Auto, i.e. outputs were never declared and mise would auto-manage them). The cache must know exactly which paths to save and restore, so either list output patterns or explicitly opt out with outputs = [].

Source

Thrown at src/task/task_cache.rs:1208

    text.escape_debug().to_string()
}

/// Returns the versioned directory containing task artifact cache entries.
pub(crate) fn task_cache_dir() -> PathBuf {
    Settings::get()
        .task
        .cache_dir
        .clone()
        .unwrap_or_else(|| dirs::CACHE.join("task-artifacts"))
        .join(CACHE_DIR_VERSION)
}

pub(crate) fn validate_config(task: &Task, root: &Path) -> Result<()> {
    if task.sources.is_empty() {
        bail!("task {} cache requires at least one source", task.name);
    }
    if task.outputs.is_auto() {
        bail!(
            "task {} cache requires explicit outputs or outputs = []",
            task.name
        );
    }
    if let Some(command) = task.cache.as_ref().and_then(|cache| {
        cache
            .command_inputs
            .iter()
            .find(|command| command.trim().is_empty())
    }) {
        bail!(
            "task {} cache command input must not be empty: {command:?}",
            task.name
        );
    }
    let patterns = task.outputs.patterns();
    if !patterns.is_empty() && output_glob_patterns(&patterns).is_empty() {
        bail!(

View on GitHub (pinned to 6f52dcdf99)

Solutions

Declare what the task produces: outputs = ["target/release/mybin", "dist/**"]
If the task produces nothing worth restoring, declare that explicitly: outputs = []
Re-run after editing to confirm validation passes before depending on the cache

Example fix

# before
[tasks.build]
cache = true
sources = ["src/**"]
run = "cargo build"

# after
[tasks.build]
cache = true
sources = ["src/**"]
outputs = ["target/debug/mybin"]

Defensive patterns

Strategy: validation

Validate before calling

python3 - <<'EOF'
import tomllib, sys
cfg = tomllib.load(open('mise.toml','rb'))
for name, t in cfg.get('tasks', {}).items():
    if t.get('cache') and 'outputs' not in t:
        sys.exit(f'{name}: cached task needs explicit outputs (or outputs = [])')
print('ok')
EOF

Prevention

Cached tasks must declare outputs explicitly — auto outputs are never cacheable
outputs = [] is the explicit 'no files' declaration

When it happens

Trigger: A cached task whose config omits any outputs key, leaving outputs in auto mode; the is_auto() check is the second validation in validate_config and fires before run.

Common situations: Turning on cache for an existing task that never declared outputs; assuming mise will figure out produced files automatically; config generated by a template that drops the outputs field.

Related errors

AI-assisted analysis of jdx/mise@6f52dcdf99 (2026-08-22). Data as JSON: /api/errors/07b1f6aa4e6ebeb8. Report an issue: GitHub.