The only kind of "review" I can do for this is to rubber stamp it.

Do you agree with throwing an error in this case? An alternative would be to just return the unmodified source.

The only kind of "review" I can do for this is to rubber stamp it.

Do you agree with throwing an error in this case? An alternative would be to just return the unmodified source.

I don't know what the ramifications are.

What's the stacktrace that gets shown?

Unfortunately it contains some wasm lines:

Error: Injection match failed
    at module.exports.__wbindgen_error_new (/Users/tim/Documents/Repositories/orchestrion-js/pkg/orchestrion_js.js:457:17)
    at wasm://wasm/00a01aba:wasm-function[3099]:0x1da003
    at wasm://wasm/00a01aba:wasm-function[2603]:0x1ccc64
    at Transformer.transform (/Users/tim/Documents/Repositories/orchestrion-js/pkg/orchestrion_js.js:283:30)
    at file:///Users/tim/Documents/Repositories/orchestrion-js/tests/wasm/tests.mjs:47:23

Open to a more useful error message is Injection match failed is not obvious enough!

I think we should try to attach some more details about the failure to the error message, like what file/function we tried to instrument.

The user supplies the library name, version and relative path to the file so it's much easier for this to be logged in JavaScript. I was saying to @bizob2828 that we should think about wrapping the wasm API with a basic JavaScript wrapper. Passing incorrect or missing parameters can cause segfaults with no stack traces. We could also use this to give more rich/helpful errors.

There are potentially multiple injections/instrumentations to apply to a file and currently we only throw an error if none are applied. Now I'm thinking about it again, we should throw if any fail to apply because many times you will be instrumenting multiple methods in a class and if any fail it's bad news!

I've changed it to error if any injection points fail and the message now includes the names of the functions which it failed to find:

Error: Failed to find injection points for: ["constructor", "fetch"]
    at module.exports.__wbindgen_error_new (/Users/tim/Documents/Repositories/orchestrion-js/pkg/orchestrion_js.js:457:17)
    at wasm://wasm/00a029da:wasm-function[3103]:0x1da3a7
    at wasm://wasm/00a029da:wasm-function[2605]:0x1ccfce
    at Transformer.transform (/Users/tim/Documents/Repositories/orchestrion-js/pkg/orchestrion_js.js:283:30)
    at file:///Users/tim/Documents/Repositories/orchestrion-js/tests/wasm/tests.mjs:47:23

Now this is merged I'm thinking of a few use cases where we might want to apply a few different instrumentations and not care about whether they ALL succeed 🤔