rollup/rollup · error

Invalid --plugin argument format: ${JSON.stringify(pluginTex

Error message

Invalid --plugin argument format: ${JSON.stringify(pluginText)}

What it means

Thrown by the Rollup CLI when the text passed to --plugin/-p does not look like a module specifier, a `name=arg` pair, or an inline object literal. The loader at cli/run/commandPlugins.ts:53 only accepts the regex `/^[\w./:@\\^{|}-]+(=(.*))?$/` once the leading `{` case is ruled out; any character outside that class (spaces, +, %, etc.) makes the argument unparseable.

Source

Thrown at cli/run/commandPlugins.ts:60

async function loadAndRegisterPlugin(
	inputOptions: InputOptionsWithPlugins,
	pluginText: string
): Promise<void> {
	let plugin: any = null;
	let pluginArgument: any = undefined;
	if (pluginText[0] === '{') {
		// -p "{transform(c,i){...}}"
		plugin = new Function('return ' + pluginText);
	} else {
		const match = pluginText.match(/^([\w./:@\\^{|}-]+)(=(.*))?$/);
		if (match) {
			// -p plugin
			// -p plugin=arg
			pluginText = match[1];
			pluginArgument = new Function('return ' + match[3])();
		} else {
			throw new Error(`Invalid --plugin argument format: ${JSON.stringify(pluginText)}`);
		}
		if (!/^\.|^rollup-plugin-|[/@\\]/.test(pluginText)) {
			// Try using plugin prefix variations first if applicable.
			// Prefix order is significant - left has higher precedence.
			for (const prefix of ['@rollup/plugin-', 'rollup-plugin-']) {
				try {
					plugin = await requireOrImport(prefix + pluginText);
					break;
				} catch {
					// if this does not work, we try requiring the actual name below
				}
			}
		}
		if (!plugin) {
			try {
				if (pluginText[0] == '.') pluginText = path.resolve(pluginText);
				// Windows absolute paths must be specified as file:// protocol URL
				// Note that we do not have coverage for Windows-only code paths

View on GitHub (pinned to ddc4ffab62)

Solutions

1. Remove characters outside [\w./:@\^{|}-] from the plugin argument (most often: stray spaces).
2. Pass inline object plugins with a leading brace: -p "{ transform(code, id) { return code } }".
3. Pass plugin options via `=`: -p node-resolve={browser:true}.
4. Separate multiple plugins with commas: -p node-resolve,commonjs.
5. Use a rollup.config.js file instead of -p for non-trivial plugin configuration.

Example fix

// before
rollup -p "node resolve"

// after
rollup -p node-resolve

// Reject invalid --plugin text before invoking the CLI loader.
const PLUGIN_SPEC_RE = /^[\w./:@\\^{|}-]+(=(.*))?$/;
function isValidPluginText(text) {
  if (typeof text !== 'string' || text.length === 0) return false;
  if (text[0] === '{') return true; // inline object plugin
  return PLUGIN_SPEC_RE.test(text);
}
if (!isValidPluginText(userPluginArg)) {
  throw new Error(`Refusing to run: bad --plugin value ${JSON.stringify(userPluginArg)}`);
}

When it happens

Trigger: Running `rollup -p "node resolve"` (space), `rollup -p "a+b"`, `rollup -p "foo#bar"`, or any plugin string containing characters outside `[\w./:@\\^{|}-]` that does not start with `{`.

Common situations: Shell quoting mistakes, copy-pasted plugin names with stray spaces, attempting to pass JSON-like option strings without the leading brace, or trying to pass multiple plugins separated by spaces instead of commas.

Related errors

• Cannot load plugin "${pluginText}": ${error.message}.
• Cannot find entry for plugin "${pluginText}". The plugin nee
• You must supply options.input to rollup
• You must supply an options object to rollup
• You must supply an options object

AI-assisted analysis of rollup/rollup@ddc4ffab62 (2026-08-03). Data as JSON: /data/errors/26023e74aae97c2a.json. Report an issue: GitHub.