Hmbown/CodeWhale · error · ExecError

hold_key on harmony supports only hold_key

Error message

hold_key on harmony supports only hold_key({"text":"click"}) = longClick

What it means

hold_key on the harmony backend is implemented as a single uiInput longClick at fixed coordinates (300,300) and therefore only accepts text === "click". Any other text throws this ExecError. The duration parameter is clamped 1-5 but the harmony uitest path does not actually vary hold length per key, so non-click holds are unsupported.

Solutions

  1. Use hold_key({text:"click"}) for long-press, and target the element first if 300,300 is not the right spot
  2. For keyboard keys use key() instead of hold_key
  3. Use perform_action({target, action:"longClick"}) to long-press a located element at its center

Example fix

// before
await backend.hold_key({ text: "enter", duration: 2 });
// after
await backend.perform_action({ target: "#send", action: "longClick" });
Defensive patterns

Strategy: validation

Validate before calling

if (action === "hold_key" && String(opts.text).toLowerCase() !== "click") {
  throw new Error("harmony backend: hold_key supports only text=click (longClick)");
}

Type guard

const isHarmonyHoldKey = (opts) => opts && typeof opts.text === "string" && opts.text.toLowerCase() === "click";

Try / catch

try {
  await backend.hold_key({ text: "click" });
} catch (e) {
  if (String(e.message).includes("hold_key on harmony")) await backend.perform_action({ target, action: "longClick" });
  else throw e;
}

Prevention

When it happens

Trigger: Calling hold_key({text:"enter"}) or hold_key({text:"a", duration:3}) on the harmonyos backend — anything except text "click" (case-insensitive).

Common situations: Reusing desktop/mobile automation scripts that long-press keyboard keys; assuming hold_key generalizes key like on other backends; trying to long-press a specific element without realizing coordinates are hardcoded to 300,300.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

AI-assisted analysis of Hmbown/CodeWhale@73e0f67d83 (2026-09-22). Data as JSON: /api/errors/e6479b40142fd26d. Report an issue: GitHub.

Appendix: source

Thrown at crates/tui/plugins/computer-use/src/backends/harmonyos.mjs:252

      const dy = direction === "up" ? dist : direction === "down" ? -dist : 0;
      return uiInput(["swipe", String(Math.round(target.x)), String(Math.round(target.y)), String(Math.round(target.x + dx)), String(Math.round(target.y + dy)), "400"]);
    },
    type: async ({ text }) => {
      if (!text) return { action_sent: false, note: "empty text" };
      await uiInput(["inputText", "300", "300", escDeviceText(text)]).catch(async (e) => {
        // Some builds require coordinates of the focused field; retry with a click-first pattern.
        throw e;
      });
      return { action_sent: true, chars: text.length, note: "inputText at 300,300 — click the field first for focused input" };
    },
    key: ({ text }) => {
      const KEYMAP = { enter: "Enter", return: "Enter", escape: "Esc", esc: "Esc", back: "Back", home: "Home", backspace: "Back", delete: "Del", tab: "Tab", left: "DPAD_LEFT", right: "DPAD_RIGHT", up: "DPAD_UP", down: "DPAD_DOWN", power: "Power", menu: "Menu" };
      const k = KEYMAP[String(text).toLowerCase()] ?? String(text);
      if (!/^[A-Za-z0-9_]+$/.test(k)) throw new ExecError(`unsupported key "${text}" on harmony backend`);
      return uiInput(["keyEvent", k]);
    },
    hold_key: async ({ text, duration }) => {
      if (String(text).toLowerCase() !== "click") throw new ExecError('hold_key on harmony supports only hold_key({"text":"click"}) = longClick');
      const d = Math.max(1, Math.min(5, Number(duration) || 1));
      return uiInput(["longClick", "300", "300"]);
    },
    set_value: async ({ target, value }) => {
      const b = await centerOf(target);
      await uiInput(["click", String(b.cx), String(b.cy)]);
      await new Promise((r) => setTimeout(r, 300));
      await uiInput(["inputText", String(b.cx), String(b.cy), escDeviceText(String(value))]);
      return { action_sent: true, strategy: "uitest-element" };
    },
    select_text: async () => { throw new ExecError("select_text is not exposed by uitest dumpLayout/uiInput on the harmony backend"); },
    perform_action: async ({ target, action }) => {
      const b = await centerOf(target);
      if (action === "longClick") return uiInput(["longClick", String(b.cx), String(b.cy)]);
      return uiInput(["click", String(b.cx), String(b.cy)]);
    },
    read_clipboard: async () => { throw new ExecError("clipboard read is not exposed by hdc on current HarmonyOS builds"); },
    write_clipboard: async () => { throw new ExecError("clipboard write is not exposed by hdc on current HarmonyOS builds"); },

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