wasm Compiled from TcpStream::connect Cannot be Deserialized in Storing

[loloicci]

wasm compiled from rust code including TcpStream::connect cannot be stored in the chain (this is as expected) and issues "Deserialization error".

create wasm contract failed: Error calling the VM: Error during static Wasm validation: Wasm bytecode could not be deserialized. Deserialization error: "I/O Error: UnexpectedEof"

This error is caused when I try to store the wasm generated by https://github.com/loloicci/cosmwasm-contract-net.

This should be other errors like "Validation error with non-deterministic op-code".

[webmaster128]

This is interesting because

Wasm bytecode could not be deserialized. Deserialization error: "I/O Error: UnexpectedEof"

means the .wasm file is broken (or at least incompatible to what the VM understand). Can you write down the exact steps build the .wasm file (please update rust-optimizer to 0.9.1 which ships a slightly updated Rust compiler)?

[loloicci]

This is happened with

docker run --rm -v "$(pwd)":/code \                                                                                          
  --mount type=volume,source="$(basename "$(pwd)")_cache",target=/code/target \
  --mount type=volume,source=registry_cache,target=/usr/local/cargo/registry \
  cosmwasm/rust-optimizer:0.9.0

When I use 0.9.1, it does not happen.

However, It can be stored and when I execute update (uses TcpStream::connect), it looks always fail to connect (returns Err(some)).
Is this behavior as expected? I think this should be judged as an invalid contract and not be stored.

[loloicci]

When I use ureq in code and compile with rust-optimizer 0.9.1, the same issue (Deserialization error) is reproduced.

https://github.com/loloicci/cosmwasm-contract-net/tree/ureq

[webmaster128]

Is this behavior as expected? I think this should be judged as an invalid contract and not be stored.

It is very well possible that the missing system calls are compiled to panics or traps when the target architecture is Wasm. The Wasm sandbox does not provide access to system APIs that would cause undeterministic behaviour. There are no Wasm ops codes for such calls, so we cannot detect that statically. In this case, the primary problem is #501.

Deserialization errors is a different story. This smells like a problem.

[loloicci]

There are no Wasm ops codes for such calls, so we cannot detect that statically. In this case, the primary problem is #501.

Thank you. I did not know that. This sounds related to #530 .

However, it looks there are some differences between #530 and this.
wasmer issues error in #530 and Err(Something) is returned in this case.
Is it a natural thing?

[loloicci]

I found that too large wasm binary causes the same error. (UnexpectedEof)

When I use ureq in code and compile with rust-optimizer 0.9.1, the same issue (Deserialization error) is reproduced.

It may due to the size of the output wasm is too large.

Does anyone know the maximum size wasmd can treat? This is maybe about 410KB as far as I tried.

[webmaster128]

We discovertred recently that wasmd has a bug which truncates wasm blobs after 400 KB without an error message. See CosmWasm/wasmd#287. If your wasm was larger than that, this explains the

Deserialization error: "I/O Error: UnexpectedEof"

It will be fixed in wasmd. Can this issue be closed or is there anything else left?

[loloicci]

It will be fixed in wasmd. Can this issue be closed or is there anything else left?

All of this is solved. Thank you! We can close this issue.