__dirname ReferenceError in Compiled Executable Using Deno Bundle and Compile with External Libraries

[xpr0gamers]

When bundling a Deno application into a single ESM file using deno bundle and then compiling it into an executable with deno compile, the resulting executable throws a ReferenceError: __dirname is not defined when executed.
This error originates from an external library (in this case, fastify-swagger), which relies on Node.js globals like __dirname that are not available or shimmed properly in the Deno environment.
The bundling process uses esbuild under the hood, which might not handle Node.js-specific globals like __dirname correctly for ESM formats or compiled executables, leading to runtime errors in dependencies.
Steps to Reproduce

1. Create a Deno project that imports and uses fastify-swagger (or any library relying on __dirname).
2. Bundle the project into a single ESM file:
   deno bundle --format=esm --output ./build/server.js --unstable-unsafe-proto --unstable-raw-imports ./src/program.ts
3. Compile the bundled file into an executable (targeting e.g., aarch64-apple-darwin):
   deno compile --allow-all --env-file --no-check --output ./build/server --target aarch64-apple-darwin --unstable-unsafe-proto --unstable-raw-imports ./build/server.js
4. Run the compiled executable: ./build/server
5. Observe the error
   error: Uncaught ReferenceError: __dirname is not defined root: opts.baseDir || path.join(__dirname, "..", "static"),

Expected Behavior
The compiled executable should run without errors related to missing Node.js globals like __dirname. External libraries should either be compatible or have necessary shims applied during bundling/compilation.
Actual Behavior
The executable fails with a ReferenceError for __dirname in the external library (fastify-swagger).
Environment

Deno version: 2.4.5
OS: macOS on Apple Silicon
Target: aarch64-apple-darwin
Library: fastify-swagger

Possible Solution
Since deno bundle uses esbuild internally, consider integrating or allowing users to add esbuild plugins to shim Node.js globals like __dirname. For example, the esbuild-shim-plugin could be used to polyfill __dirname (along with __filename, require, etc.) during the bundling process. This would make the output more compatible with Node.js-style libraries in Deno executables.
If this is not feasible, providing documentation or built-in flags to handle such shims would be helpful.

[bartlomieju]

Do you have a repo we could try to reproduce this with?

[xpr0gamers]

Do you have a repo we could try to reproduce this with?

https://github.com/xpr0gamers/deno-error-dirname