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I was debugging some chunking regressions in an app I work on when updating from Vite 7 to Vite 8. I got an AI to generate a tool to help figuring out what was wrong, and I uploaded it at nicolo-ribaudo.github.io/vite-compare/ in case it's useful for anybody else.

nicolo-ribaudo.github.ioVite bundle compareCompare two Vite bundle builds side-by-side: chunk diff, per-entry size analysis, module diff, and an interactive chunk/module graph.

Alexander Lichter

@thealexlichter.com

29 Apr

Thanks for sharing! What was the outcome in your case(s)? 👀

Nicolò Ribaudo

@nicr.dev

29 Apr

Rolldown was over-splitting compared to Rollup, I had to manually configure some groups. It has something to do with cycles across chunks and modules imported both through a static and dynamic imports chain, but I cannot get a minimal reproduction to show the same behavior.

Alexander Lichter

@thealexlichter.com

29 Apr

Interesting! Did you try using `attachDebugInfo` (which should give insights why certain chunks were created)? rolldown.rs/reference/In...

rolldown.rsRolldown | Rust bundler for JavaScriptFast Rust-based bundler for JavaScript with Rollup-compatible API

Nicolò Ribaudo

@nicr.dev

Tried now, unfortunately it's not very helpful. In my case it's telling me that chunk C is its own chunk because it's imported both by chunk A and chunk B, which is indeed true, but it does not explain why it cannot just put it inside chunk A (where chunk B is only imported through import() by A)

29/4/26, 4:01 pm0 reposts1 like

Nicolò Ribaudo

@nicr.dev

29 Apr

I'll see if I can create a reproduction in the next days