Foundry376/Mailspring · error · InvalidPackageNameError

Plugin in ${dir} has an invalid or missing "name" field. Nam

Error message

Plugin in ${dir} has an invalid or missing "name" field. Names must match /^[a-zA-Z0-9._-]+$.

What it means

InvalidPackageNameError thrown from the Plugin class constructor while loading a plugin's package.json: the manifest parsed but its name field is missing or contains characters outside /^[a-zA-Z0-9._-]+$. Fires at startup when scanning plugin directories (internal_packages and user plugins).

Source

Thrown at app/src/package.ts:46

  public windowTypes: { [windowName: string]: boolean };
  private json: any;

  constructor(dir: string) {
    this.directory = dir;

    let jsonString = null;
    try {
      jsonString = fs.readFileSync(path.join(dir, 'package.json')).toString();
    } catch (err) {
      // silently fail, not a file
    }
    if (!jsonString) {
      throw new NoPackageJSONError();
    }

    this.json = JSON.parse(jsonString);
    if (!isValidPackageName(this.json.name)) {
      throw new InvalidPackageNameError(
        `Plugin in ${dir} has an invalid or missing "name" field. Names must match /^[a-zA-Z0-9._-]+$/.`
      );
    }
    this.name = this.json.name;
    this.displayName = this.json.displayName || this.json.name;
    this.syncInit = this.json.syncInit;
    this.windowTypes = this.json.windowTypes || { default: true };
  }

  activate() {
    const start = Date.now(); // eslint-disable-line

    this.loadKeymaps();
    this.loadMenus();
    this.loadStylesheets();

    if (this.json.main) {
      const root = path.join(this.directory, this.json.main);

View on GitHub (pinned to 648c685d60)

Solutions

1. Edit the plugin's package.json and set a name matching /^[a-zA-Z0-9._-]+$/ (letters, digits, dot, underscore, hyphen only — no spaces)
2. Remove or uninstall the offending plugin if it is not needed
3. Check third-party plugins installed into the user plugins directory

When it happens

Trigger: Thrown at app/src/package.ts:46 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of Foundry376/Mailspring@648c685d60 (2026-09-03). Data as JSON: /api/errors/a77d8932bb618073. Report an issue: GitHub.