The `build.output.banner` is configured but not taking effect.

[ZiuChen]

Describe the bug

I configured a comment string for the banner option using rolldown-vite, but after building, the banner wasn't added to the final code.

rolldown document

Reproduction

https://stackblitz.com/edit/vitejs-vite-h1qdagdd?file=vite.config.ts

Steps to reproduce

1. npm install
2. npm run build

System Info

System:
    OS: Linux 5.0 undefined
    CPU: (8) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
    Memory: 0 Bytes / 0 Bytes
    Shell: 1.0 - /bin/jsh
  Binaries:
    Node: 20.19.1 - /usr/local/bin/node
    Yarn: 1.22.19 - /usr/local/bin/yarn
    npm: 10.8.2 - /usr/local/bin/npm
    pnpm: 8.15.6 - /usr/local/bin/pnpm
  npmPackages:
    rolldown-vite:  7.1.19

Used Package Manager

npm

Logs

Log exceeds GitHub's maximum character limit for input fields. Please forgive me for using file upload instead.

build.log

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs and the Rolldown-related guide.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.

[sapphi-red]

It is removed by the minifier because the comment is not a license comment (comments containing @license, @preserve, or starting with //! or /*!).

[ZiuChen]

It is removed by the minifier because the comment is not a license comment (comments containing @license, @preserve, or starting with //! or /*!).

Thank you very much for your investigation.
I think it might be more appropriate to add some additional explanations to this section in document to prevent more people from encountering attribute conflicts.
Alternatively, could we adjust the strategy: have the minifier ignore comments that explicitly configure the build.output.banner property?

[sapphi-red]

Adding a explanation to the docs makes sense. It would be great if you can send a PR.

Alternatively, could we adjust the strategy: have the minifier ignore comments that explicitly configure the build.output.banner property?

I think it's difficult to do so.

[ZiuChen]

Adding a explanation to the docs makes sense. It would be great if you can send a PR.

I would be happy to submit a PR for this later today.

Alternatively, could we adjust the strategy: have the minifier ignore comments that explicitly configure the build.output.banner property?

I think it's difficult to do so.

Actually, I believe the behavior of adding the banner should be executed after the minifier: after the minifier completes code compression, the banner should then be added to the code.

Of course, I understand that Vite, as a hybrid architecture build tool in the past, faced some difficulties in coordinating different toolchains. However, now that both rolldown and its minifier are implemented in Rust, shouldn't it be easier to customize their execution order and behavior?

Apologies, I'm not very familiar with the core architecture of rolldown-vite. If there are any inaccuracies in my perspective, please forgive my ignorance.

[sapphi-red]

Adding the banner after the minifier doesn't work well with the existing behavior of Rollup. Rollup runs banner before renderChunk hooks (repro). If we want to run the minification before banner, renderChunk would have to handle minified code and keep them minified (which is difficult).If we move banner after the minification, that may cause problems as well, as users may expect the banner to be injected before renderChunk hooks are called.

[ZiuChen]

I understand, thank you for your answer. This may not be an easy problem to solve