withfig/autocomplete · error · Error

Failed to parse alias

Error message

Failed to parse alias

What it means

In this Fig-style completion spec, a generator runs `gh alias list`, splits the output by lines, and looks for a line beginning with `<token>:\t` (name, colon, tab). If no line matches — meaning GitHub CLI returned no alias with that name or its output format differs — the spec throws this Error to abort alias completion.

Source

Thrown at src/gh.ts:274

  name: "gh",
  description: "GitHub's CLI tool",
  args: {
    name: "alias",
    description: "Custom user defined gh alias",
    isOptional: true,
    generators: ghGenerators.listAlias,
    parserDirectives: {
      alias: async (token, executeShellCommand) => {
        const { stdout } = await executeShellCommand({
          command: "gh",
          args: ["alias", "list"],
        });
        const alias = stdout
          .split("\n")
          .find((line) => line.startsWith(`${token}:\t`));

        if (!alias) {
          throw new Error("Failed to parse alias");
        }

        return alias.slice(token.length + 1).trim();
      },
    },
  },
  subcommands: [
    {
      name: "alias",
      description: "Create command shortcuts",

      subcommands: [
        {
          name: "delete",
          description: "Delete an alias",
          args: {
            name: "alias",
            generators: ghGenerators.listAlias,

View on GitHub (pinned to aef52acff8)

Solutions

1. Run `gh alias list` and confirm an alias with exactly the typed name exists (`gh alias list | grep '^name:'`)
2. Create the missing alias with `gh alias set <name> '<command>'`
3. Check for whitespace/format drift: if your gh version does not emit a tab after the colon, relax the prefix match in the spec
4. Verify `gh` is on PATH and authenticated (`gh auth status`) so the generator's command succeeds

Example fix

// before
const alias = stdout
  .split("\n")
  .find((line) => line.startsWith(`${token}:\t`));
// after (tolerant of tab or spaces after the colon)
const alias = stdout
  .split("\n")
  .find((line) => new RegExp(`^${token}:\\s`).test(line));

import { execSync } from "child_process";
export function ghAliasExists(token: string): boolean {
  try {
    const out = execSync("gh alias list", { encoding: "utf8" });
    return new RegExp(`^${token}:\\s`, "m").test(out);
  } catch {
    return false;
  }
}
if (!ghAliasExists("co")) throw new Error("gh alias 'co' not configured");

function isAliasLine(line: string, token: string): line is `${string}:\t${string}` {
  return line.startsWith(`${token}:\t`) || new RegExp(`^${token}:\\s`).test(line);
}

try {
  const script = await getAlias(token);
} catch (err) {
  if (err instanceof Error && err.message === "Failed to parse alias") {
    // treat as "no such alias": suggest `gh alias list` or fall back to default completions
    return [];
  }
  throw err;
}

When it happens

Trigger: The `token` argument does not match any alias name printed by `gh alias list`; `gh` prints aliases in a different format (e.g. no tab separator after the colon, older gh versions); or the generator's `gh alias list` command silently succeeds with empty output while an alias lookup was expected.

Common situations: User typed an alias name with different casing or a typo; gh CLI is not authenticated or has no aliases configured; a gh version change altered `gh alias list` output formatting (removed the tab); user defined aliases only in git but not gh.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• Failed parsing alias
• npm prefix command failed

AI-assisted analysis of withfig/autocomplete@aef52acff8 (2026-08-31). Data as JSON: /api/errors/50c4b7c13c88864a. Report an issue: GitHub.