What causes "Invalid 'out' in OutputForm" in sxyazi/yazi?

Attach the task output under key 'out' when constructing the tasks.output action.

Invalid 'out' in OutputForm

Error message

Invalid 'out' in OutputForm

What it means

OutputForm carries a completed task's id and its 'out' value (process output channel/data) back to a waiting caller. Both fields are required: 'id' is fetched with a.get("id")? (its own conversion error possible), and 'out' with a.take_any("out") — if 'out' is missing or of the wrong type, "Invalid 'out' in OutputForm" is raised. Without it the replier cannot deliver the task output.

Solutions

Attach the task output under key 'out' when constructing the tasks.output action.
Also ensure a valid task 'id' is present, since get("id")? runs before 'out' is checked.
Match the out type to OutputForm in yazi-parser/src/tasks/output.rs for your yazi version.
Reply via the task's built-in replier/callback path rather than assembling the action by hand.

Example fix

// before
let a = ActionCow::from("tasks.output").with("id", id); // missing out
// after
let a = ActionCow::from("tasks.output").with("id", id).with("out", out);

Defensive patterns

Strategy: validation

Validate before calling

if action.get("id").is_err() || !action.has("out") {
    anyhow::bail!("tasks.output requires both 'id' and 'out'");
}
let form = OutputForm::try_from(action)?;

Type guard

fn has_out(a: &ActionCow) -> bool { a.has("out") }

Try / catch

match OutputForm::try_from(action) {
    Ok(form) => form.reply(),
    Err(e) => tracing::error!("task reply dropped: {e:#}"),
}

Prevention

Always reply through the task's replier so id and out are attached together.
Check 'id' first — get("id")? fails before the 'out' check.
Keep output payload types aligned with OutputForm after upgrades.

When it happens

Trigger: Dispatching tasks.output without an 'out' entry, or with an 'out' value that cannot be taken as the expected output type; also if 'id' is missing/invalid the get("id")? error fires first.

Common situations: Custom task implementations replying without attaching the output value; version drift in the output payload representation; forwarding the reply through code that drops extra values.

Related errors

AI-assisted analysis of sxyazi/yazi@5f901b886b (2026-09-02). Data as JSON: /api/errors/acdc9487e22bfbee. Report an issue: GitHub.

Appendix: source

Thrown at yazi-parser/src/tasks/output.rs:18

use anyhow::anyhow;
use mlua::{ExternalError, FromLua, IntoLua, Lua, Value};
use yazi_scheduler::custom::CustomOut;
use yazi_shared::{event::ActionCow, id::Id};

#[derive(Debug)]
pub struct OutputForm {
	pub id:  Id,
	pub out: CustomOut,
}

impl TryFrom<ActionCow> for OutputForm {
	type Error = anyhow::Error;

	fn try_from(mut a: ActionCow) -> Result<Self, Self::Error> {
		Ok(Self {
			id:  a.get("id")?,
			out: a.take_any("out").ok_or_else(|| anyhow!("Invalid 'out' in OutputForm"))?,
		})
	}
}

impl FromLua for OutputForm {
	fn from_lua(_: Value, _: &Lua) -> mlua::Result<Self> { Err("unsupported".into_lua_err()) }
}

impl IntoLua for OutputForm {
	fn into_lua(self, _: &Lua) -> mlua::Result<Value> { Err("unsupported".into_lua_err()) }
}

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