This repository reproduces an apparent bug in the Bun runtime plugin onResolve
method implemenation when it comes to synchronous and asychronous module
imports.
Start off by running bun install to fetch the TypeScript types for Bun.
Next up, check the runtime plugin implementation in plugin.ts.
You can see it uses onResolve to re-map an import specifier to a different
path (./sync.demo to ./sync.ts and ./async.demo to ./async.ts).
bunfig.toml's preload is used to register the plugin.
Run bun index.ts to see the plugin in action.
It will print a line showing the plugin is successfully registered.
There are two imports, one synchronous and another, asynchronous.
We'll see two more lines showing onResolve is called for the sync path and
then the default export printing correctly.
After, we see another onResolve call, but this time, the load fails with an
ENOENT error despite async.ts existing.
Plugin loaded
onResolve called ./sync.demo
Sync demo Hello, sync!
onResolve called ./async.demo
Error loading async demo error: ENOENT reading "file:./async.ts"
We can try to fix this by prepending import.meta.dir to path in onResolve,
but this won't help:
Plugin loaded
onResolve called ./sync.demo
Sync demo Hello, sync!
onResolve called ./async.demo
Error loading async demo error: ENOENT reading "file:/…/async.ts"
The problem seems to be specific to asynchronous imports.
I have also discovered an issue with onResolve not being fired for custom
protocol: