Bun.build (with target browser) produces nodejs target if the dependency is imported in the same script that runs Bun.build

[spirobel]

What version of Bun is running?

1.1.29

What platform is your computer?

Linux 6.8.0-45-generic x86_64 x86_64

What steps can reproduce the bug?

The webframework that I wrote for bun has a function to build frontends. ( url.frontend("nameOfFrontendEntrypoint.tsx") )
It populates an array with the name of the frontend. To build them, the build function imports the backend code that the consumer (/developer) of this webframework wrote. This executes all the invocations of url.frontend and populates the array with all the frontend files that are to be built.

The issue is that if the frontend and the backend use the same library (that is different depending on if it is used in the browser or nodejs. But still the same npm package. @solana/web3.js is an example for that) then the compiled frontend will complain about missing nodejs features like buffer, process, https, global and so on. This is not the case if it is not imported in the backend. If it is just imported in the frontend, the Bun.build works perfectly fine. It seems to only get triggered if it is imported in the same .ts file that runs Bun.build

I made a change now that runs the Bun.build code in a different process:
spirobel/mininext@5d45fd9
this change made the issue disappear. So the assumption is, that during Bun.build, imports are cached somehow. I started to read the source code

bun/src/bun.js/api/JSBundler.zig

Line 538 in 9ab5198

return bun.BundleV2.generateFromJavaScript(

https://github.com/oven-sh/bun/blob/main/src/bundler/bundle_v2.zig but I dont have much time to dig deeper. I assume that the import gets visited first and is then cached and reused even though the target is different.

TLDR: use mininext v 0.5.1 and use @solana/web3.js in both frontend and backend.

What is the expected behavior?

the expected behavior is that Bun.build with target browser produces a bundle that is not dependent on a nodejs library, regardless of if the library is imported in the script that runs Bun.build or not.

The issue is that if the frontend and the backend use the same library (that is different depending on if it is used in the browser or nodejs. But still the same npm package. @solana/web3.js is an example for that) then the compiled frontend will complain about missing nodejs features like buffer, process, https, global and so on. This is not the case if it is not imported in the backend. If it is just imported in the frontend, the Bun.build works perfectly fine. It seems to only get triggered if it is imported in the same .ts file that runs Bun.build

What do you see instead?

The issue is that if the frontend and the backend use the same library (that is different depending on if it is used in the browser or nodejs. But still the same npm package. @solana/web3.js is an example for that) then the compiled frontend will complain about missing nodejs features like buffer, process, https, global and so on. This is not the case if it is not imported in the backend. If it is just imported in the frontend, the Bun.build works perfectly fine. It seems to only get triggered if it is imported in the same .ts file that runs Bun.build

Additional information

I can produce an example repo if necessary. lmk if you can not reproduce / something is unclear