Can't Call FromBinary() On a WASM File

Here are the steps to recreate the issue:

Go here, http://mbebenita.github.io/WasmExplorer/, and enter in this text for the “Wast”:

(module
  (export "collatz" (func $_Z7collatzi))
  (func $_Z7collatzi (param $0 i32) (result i32)
    (local $1 i32)
    (set_local $1
      (i32.const 0)
    )
    (block $label$0
      (br_if $label$0
        (i32.lt_s
          (get_local $0)
          (i32.const 2)
        )
      )
      (set_local $1
        (i32.const 0)
      )
      (loop $label$1
        (set_local $1
          (i32.add
            (get_local $1)
            (i32.const 1)
          )
        )
        (br_if $label$1
          (i32.gt_s
            (tee_local $0
              (select
                (i32.add
                  (i32.mul
                    (get_local $0)
                    (i32.const 3)
                  )
                  (i32.const 1)
                )
                (i32.div_s
                  (get_local $0)
                  (i32.const 2)
                )
                (i32.and
                  (get_local $0)
                  (i32.const 1)
                )
              )
            )
            (i32.const 1)
          )
        )
      )
    )
    (get_local $1)
  )
)

Press “Assemble” and then “Download”. You should have a test.wasm file in your Downloads folder.

Now, create a C# project that references the WebAssembly package. Move test.wasm to that project’s folder. Create this code in the Main() method:

Compile.FromBinary<dynamic>("collatz.wasm");

I get the following error: Unhandled Exception: WebAssembly.ModuleLoadException: At offset 124: Stream ended unexpectedly. —> System.IO.EndOfStreamException: Unable to read beyond the end of the stream. at System.IO.__Error.EndOfFile() at System.IO.BinaryReader.ReadByte() at WebAssembly.Reader.ReadByte() at WebAssembly.Reader.ReadVarInt32() at WebAssembly.Compile.FromBinary(Reader reader, Type instanceContainer, Type exportContainer) at WebAssembly.Compile.FromBinary[TExports](Stream input) — End of inner exception stack trace — at WebAssembly.Compile.FromBinary[TExports](Stream input) at WebAssembly.Compile.FromBinary[TExports](String path) at WasmToAssembly.Program.Main(String[] args)

However, if I go here - https://wasdk.github.io/wasmcodeexplorer/ - and load test.wasm, it shows up with no errors and the wast is generated correctly on the right-hand side.

[RyanLamansky]

Fixed! This problem was the only thing preventing your code from running 😁

Are you able to grab the updated code from GitHub or do you need a new package?

[RyanLamansky]

Thanks for the report! Typically this error indicates that the “end” instruction is missing but the disassembly tool you linked showed it as present. I’ll take a deeper look in a day or two.