jsoverson
commented
1 year ago @Kerosin3 Thanks for the issue! The hotswapping implementation has been around for ages. I (and apparently others) haven't exercised it in a while. It looks like the implementation retains a reference to the original guest call function so every subsequent send will use the original module's export.
Change the implementation of replace() in wasmtime-provider to the following to fix it:
fn replace(
&mut self,
module: &[u8],
) -> std::result::Result<(), Box<(dyn std::error::Error + Send + Sync + 'static)>> {
info!(
"HOT SWAP - Replacing existing WebAssembly module with new buffer, {} bytes",
module.len()
);
let module = Module::new(&self.engine, module)?;
self.module = module;
self.instance_pre = self.linker.instantiate_pre(&self.module)?;
let new_instance = self.instance_pre.instantiate(&mut self.store)?;
if let Some(inner) = self.inner.as_mut() {
*inner.instance.write() = new_instance;
let gc = guest_call_fn(&mut self.store, &inner.instance)?;
inner.guest_call_fn = gc;
}
Ok(self.initialize()?)
}
Kerosin3
Hello! I'm trying to perform a simple task inside a wasm module (calcing hash of a data supplied) and also preforming hot module-switching. The problem is that I'm not getting an expected results. There are no errors neither in log, nor in the app, still, I get the output as if just one module was instantiated, debug log shows that only I am calling only the first module (modules functionality slightly differs, so I should have a different output after deserialization).
Can you tell me if I am doing something wrong based on the code or based on running the example I supplied? here is a fork with example I wrote. (just run
cargo run -p wasmtime-provider --example wasmtime-hash-mreplace somethingin wasmtime-provider)https://github.com/Kerosin3/wapc-rs-m/tree/develop