EIP-1193 crash if no ethereum object

[SionoiS]

Would be cool if it returned a nice error message when the user has no compatible wallet installed with their browser instead of crashing.

[tomusdrw]

Can you provide a code sample? Which line exactly crashes the app?

[SionoiS]

The ethereum object is undefined.

index-31f41f846045dd9b.js:664 Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'on')
    at imports.wbg.__wbg_on_0f85c0c3add89018 (index-31f41f846045dd9b.js:664)
    at web3::transports::eip_1193::Provider::on::haa90b8451281dff2 (index-31f41f846045dd9b_bg.wasm:0x82b319)
    at web3::transports::eip_1193::ProviderAndListeners::on::h67c1a9a03ee86ffa (index-31f41f846045dd9b_bg.wasm:0x69629c)
    at web3::transports::eip_1193::Eip1193::new::h1777e4e309433e74 (index-31f41f846045dd9b_bg.wasm:0x52cd75)
    at web_app::utils::web3::Web3Service::new::he41951d6e5f8c511 (index-31f41f846045dd9b_bg.wasm:0x4db8ad)
    at web_app::main::h44cf0902015ad00d (index-31f41f846045dd9b_bg.wasm:0x605eb5)
    at core::ops::function::FnOnce::call_once::h1a851f6194f89d40 (index-31f41f846045dd9b_bg.wasm:0xa198ef)
    at std::sys_common::backtrace::__rust_begin_short_backtrace::he2f30625ce35cc33 (index-31f41f846045dd9b_bg.wasm:0xa0908c)
    at std::rt::lang_start::{{closure}}::h300b60a332ccf4f7 (index-31f41f846045dd9b_bg.wasm:0x9cbbaf)
    at std::rt::lang_start_internal::h6c264208183e517c (index-31f41f846045dd9b_bg.wasm:0x73d00a)

It should return an error when the ethereum object is not present.

That's line

rust-web3/src/transports/eip_1193.rs

Line 225 in 2e2d1df

fn on(_: &Provider, eventName: &str, listener: &Closure<dyn FnMut(JsValue)>);

[tomusdrw]

Sorry, but this is not specific enough for me. What do you mean by "it should return an error"? Which part of the code should error out?

The way I see it is we could change the bindgen to return Result<Option<Provider>, JsValue> here and then force the user to handle non-existence in case of using Provider::default().

Can you please share the exact code you are using and how you expect this to be handled?

[SionoiS]

Yes, returning an Option is fine, no need for an error.

 pub fn default() -> Result<Option<Self>, JsValue> { 

instead of

rust-web3/src/transports/eip_1193.rs

Line 233 in 2e2d1df

pub fn default() -> Result<Self, JsValue> {

and

fn get_provider_js() -> Result<Option<Provider>, JsValue>;

instead of

rust-web3/src/transports/eip_1193.rs

Line 281 in 2e2d1df

fn get_provider_js() -> Result<Provider, JsValue>;

I will send a PR.