Allow dlopen(…) to accept file://… so that values from import.meta.resolve(…) can be directly passed in again

[lgarron]

What version of Bun is running?

1.1.0

What platform is your computer?

Darwin 23.4.0 arm64 arm

What steps can reproduce the bug?

// The `await` can be removed in `bun` 1.1.0
dlopen(await import.meta.resolve(`./ffi.dylib`), {
  // …
})

What is the expected behavior?

The code works, as it did in bun 1.0.34.

What do you see instead?

Thanks to #5827 import.meta.resolve is now synchronous (which is fantastic for interop) and returns file:// URLs as strings to match node (certainly handy to have consistency!).

Unfortunately, dlopen currently fails when given a file:// scheme, so these changes broke some code. The workaround for this is not entirely obvious, as it requires re-parsing the resolved path as a URL:

// The `await` can be removed in `bun` 1.1.0
dlopen(new URL(await import.meta.resolve(`./ffi.dylib`)).pathname, {
  // …
})

It errors with:

ERR_DLOPEN_FAILED: Failed to open library. This is usually caused by a missing library or an invalid library path.

Since dlopen(…) isn't matching the functionality of an existing node API, I'd love to see it accept file URLs so that resolved path cans be passed to it intuitively and ergonomically. I think this is particularly valuable because:

• This would make it super straightforward to write maximally portable code by writing the obvious, concise thing.
• By contrast, the existing error message might make someone go double-check and triple-check for the existence of the relevant file, only to be left scratching their heads. ("The path is valid! bun is handing me a resolved path to a file that definitely exists!") It's a real red herring, and even with a lot of expertise it took me a few minutes to figure out what was going on.

Additional information

No response

[lgarron]

Thanks for implementing this so quickly, this is really nice to have! 🤩

[lgarron]

Actually, it looks like this isn't quite working yet?

git clone https://github.com/cubing/twsearch && cd twsearch
git checkout 6279f4abbee4ac8941d7cd5648c6811eb283cb0a
cargo install cargo-run-bin # Requires `cargo` to be installed already.
make build-rust-ffi
bun run "src/rs-ffi/test/js_test.ts"

bun v1.1.1 on macOS still errors with ERR_DLOPEN_FAILED: Failed to open library. This is usually caused by a missing library or an invalid library path.

Should I file a new issue?