Possible bug - output comes with code instrumentation for CJS/require

[thednp]

I'm not sure if this is a bug or not, but I've updated my libraries dependencies with tsdown v0.21.4 and some strange new code which looks like instrumentation for CJS/require compatibility, but for all formats excluding CJS.

Example

(() => {
	var table = new Uint8Array(128);
	for (var i = 0; i < 64; i++) table[i < 26 ? i + 65 : i < 52 ? i + 71 : i < 62 ? i - 4 : i * 4 - 205] = i;
	return (base64) => {
		var n = base64.length, bytes = new Uint8Array((n - (base64[n - 1] == "=") - (base64[n - 2] == "=")) * 3 / 4 | 0);
		for (var i = 0, j = 0; i < n;) {
			var c0 = table[base64.charCodeAt(i++)], c1 = table[base64.charCodeAt(i++)];
			var c2 = table[base64.charCodeAt(i++)], c3 = table[base64.charCodeAt(i++)];
			bytes[j++] = c0 << 2 | c1 >> 4;
			bytes[j++] = c1 << 4 | c2 >> 2;
			bytes[j++] = c2 << 6 | c3;
		}
		return bytes;
	};
})();
((x) => typeof require !== "undefined" ? require : typeof Proxy !== "undefined" ? new Proxy(x, { get: (a, b) => (typeof require !== "undefined" ? require : a)[b] }) : x)(function(x) {
	if (typeof require !== "undefined") return require.apply(this, arguments);
	throw Error("Calling `require` for \"" + x + "\" in an environment that doesn't expose the `require` function. See https://rolldown.rs/in-depth/bundling-cjs#require-external-modules for more details.");
});

This code is imported into the index.js of the output. Here's a repository you can check/read and determine what happens and test yourselves.

Questions:

• is this a bug? (probably we're preparing for a complete retire of CJS/require format coming soon and kinda trendy lately?)
• is this a security feature? (looking at the Uint8Array, this makes me think it might be something for encryption?)
• if this this is a bug when can we expect a fix for it?

Thank you for you hard work.
Cheers!

[sxzz]

This behavior is affected by vite-plugin-strip-comments. The plugin should exclude \x00rolldown/runtime.js from transformation.

[thednp]

Thank you, that fixes it.

[thednp]

It would probably be helpful to have a list of internal modules we need to skip transformation for. Just an idea.

[sxzz]

Just this one for now.