':task' pattern should be expanded before matching

Error message

':task' pattern should be expanded before matching

What it means

The `:task` monorepo pattern (current-directory task) is expected to be expanded into a concrete task reference before monorepo pattern matching runs. Reaching the matching function with an unexpanded `:`-prefixed pattern indicates an internal expansion step was skipped — mise treats it as an invariant violation rather than matching incorrectly.

Source

Thrown at src/task/mod.rs:3489

                .map(|(_, task)| task)
                .unique()
                .collect();
            if !ext_stripped.is_empty() {
                return Ok(ext_stripped);
            }
            if self.keys().any(|k| k.starts_with("//")) {
                return self.get_matching(&format!("//{pat}"));
            }
            return Ok(vec![]);
        }

        // === Parse monorepo pattern ===
        let normalized_pat = if pat.starts_with("//") {
            pat.to_string()
        } else if pat.starts_with(':') {
            // Special case: :task should have been expanded before calling get_matching
            // If we reach here, it means the expansion didn't happen properly
            bail!("':task' pattern should be expanded before matching")
        } else {
            pat.to_string()
        };

        // Split pattern into path and task parts
        // Pattern format: //path/...:task* or //path:task*
        let parts: Vec<&str> = normalized_pat.splitn(2, ':').collect();
        if pat.starts_with("//") && parts.len() == 1 {
            bail!(
                "missing task name in monorepo path '{}', use '{}:<task>' or '{}:*' to run all tasks in that path",
                pat,
                pat,
                pat
            );
        }
        let (path_pattern, task_pattern) = match parts.as_slice() {
            [path, task] => (*path, *task),
            [path] => (*path, "*"),

View on GitHub (pinned to afd2eddd3a)

Solutions

Update mise to the latest version — this usually indicates a bug in the expansion step
If calling internals, expand `:task` to `//<abs-or-project-relative-path>:task` before invoking get_matching
Report the issue to mise with the command that produced it (file a bug with reproduction steps)

Example fix

// before (caller code)
get_matching(":build", ...)

// after (caller code)
let expanded = format!("//{}:build", project_relative_dir);
get_matching(&expanded, ...)

Defensive patterns

Strategy: retry

Try / catch

# shell
if mise run ":build" 2>&1 | grep -q "should be expanded before matching"; then
  mise upgrade   # likely a mise bug; retry on latest
fi

Prevention

Keep mise up to date; this indicates an internal expansion bug, not user error
Avoid passing raw `:task` selectors to internal/API surfaces from scripts
Report reproducible occurrences upstream with MISE_DEBUG=1 output

When it happens

Trigger: Calling the internal monorepo pattern matcher `get_matching` with a pattern like `:build` that should have been expanded to `//<current-dir>:build` beforehand; can surface via CLI paths that bypass normal expansion.

Common situations: Mostly an internal/edge-case error; users may see it if tooling (scripts, plugins) invokes task matching APIs with raw `:task` selectors, or from undiscovered code paths after a mise version change.

Understand the failure class

Background: "This is a bug, please report it": internal invariant violations, unreachable panics, and SNH errors explained — this error's family across 47 libraries.

Related errors

AI-assisted analysis of jdx/mise@afd2eddd3a (2026-09-09). Data as JSON: /api/errors/4c38f897535f7ced. Report an issue: GitHub.