Bug report: Treat resource type errors as string type.

[xiaozzzZZzzz240]

cplusplus.zip
generated_wit_00000.wit.zip
generated_wit_00000b.wit.zip
python.zip
world0-pvwxtgtmlk_fromPython.wasm.zip
world1-consumer_fromC++_importworld0-pvwxtgtmlk_fromPython.wasm.zip
world1-consumer_fromC++.wasm.zip

Summary

Using these two WIT files, we implemented them in C++ and Python respectively, and finally compiled them into Wasm component files. We executed them in wasmtime and jco. wasmtime ran correctly, but jco crashed.

Environment

jco 1.16.1
wasmtime 41.0.0
OS: macOS Sequoia 15.7
CPU: Intel Core i7

Reproduce steps

The specific reproduction steps are as follows:

1. Use the following command to generate Python binding files from generated_wit_00000.wit.
   componentize-py -d xxx/witfiles/package3hl16smu1p -w world0-pvwxtgtmlk bindings xxx/python/world0-pvwxtgtmlk

2. Implement the Python program as shown in python.zip.

3. Use the following command to generate Wasm component file from Python.
   cd xxx/python/world0-pvwxtgtmlk
componentize-py --wit-path xxx/witfiles/package3hl16smu1p --world world0-pvwxtgtmlk componentize world0-pvwxtgtmlk_generated -o xxx/componentfiles/world0-pvwxtgtmlk_fromPython.wasm

4. Use the following command to generate C++ binding files from generated_wit_00000b.wit.
   wit-bindgen cpp xxx/witfiles/package3hl16smu1p --world world1-consumer --out-dir xxx/cplusplus/world1-consumer

5. Implement the C++ program as shown in cplusplus.zip.

6. Use the following command to generate Wasm component file from C++.
   xxx/WASI/wasi-sdk-27.0/wasi-sdk-27.0-x86_64-macos/bin/wasm32-wasip2-clang++ -std=c++23 -o xxx/componentfiles/world1-consumer_fromC++.wasm -mexec-model=reactor xxx/cplusplus/world1-consumer/world1-consumer_generated.cpp xxx/cplusplus/world1-consumer/world1_consumer.cpp xxx/cplusplus/world1-consumer/world1_consumer_component_type.o

7. Use wac to combine the two Wasm component files:
   wac plug xxx/componentfiles/world1-consumer_fromC++.wasm --plug xxx/componentfiles/world0-pvwxtgtmlk_fromPython.wasm -o xxx/componentfiles/world1-consumer_fromC++_importworld0-pvwxtgtmlk_fromPython.wasm

8. Use wasmtime to run the final Wasm component file:
   wasmtime run world1-consumer_fromC++_importworld0-pvwxtgtmlk_fromPython.wasm
   Wasmtime prints:

[dbg] run: minimal begin
[dbg] py: open_temp begin
[dbg] py: handle.__init__ path=mem://h-1
[dbg] py: open_temp end path=mem://h-1
[dbg] run: before append
[dbg] py: handle.append begin path=mem://h-1 data=|x|
[dbg] py: handle.append end path=mem://h-1 size=3
[dbg] run: after append

9. Use jco to run the same final Wasm component file:
   jco run world1-consumer_fromC++_importworld0-pvwxtgtmlk_fromPython.wasm
   jco prints:

[dbg] run: minimal begin
[dbg] py: open_temp begin
[dbg] py: handle.__init__ path=mem://h-1
[dbg] py: open_temp end path=mem://h-1
[dbg] run: before append
AttributeError: '' object has no attribute 'append'

thread '<unnamed>' panicked at runtime/src/lib.rs:499:21:
Python function threw an unexpected exception
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
RuntimeError: unreachable
    at libc.so.abort (wasm://wasm/libc.so-001e65fe:wasm-function[458]:0x1041d)
    at wasm://wasm/02a675a6:wasm-function[306]:0xf8e8
    at libcomponentize_py_runtime.so.std::sys::pal::wasi::helpers::abort_internal::h118dde344a79086c (wasm://wasm/libcomponentize_py_runtime.so-0052fcc2:wasm-function[2193]:0xceb72)
    at libcomponentize_py_runtime.so.std::process::abort::h2738589d00d7233e (wasm://wasm/libcomponentize_py_runtime.so-0052fcc2:wasm-function[1645]:0xb87f6)
    at libcomponentize_py_runtime.so.__rustc::__rust_abort (wasm://wasm/libcomponentize_py_runtime.so-0052fcc2:wasm-function[2002]:0xc7330)
    at libcomponentize_py_runtime.so.__rustc::__rust_start_panic (wasm://wasm/libcomponentize_py_runtime.so-0052fcc2:wasm-function[2208]:0xcfc4c)
    at libcomponentize_py_runtime.so.__rustc::rust_panic (wasm://wasm/libcomponentize_py_runtime.so-0052fcc2:wasm-function[2035]:0xc8a1e)
    at libcomponentize_py_runtime.so.std::panicking::rust_panic_with_hook::h02d894de16d94192 (wasm://wasm/libcomponentize_py_runtime.so-0052fcc2:wasm-function[2034]:0xc899c)
    at libcomponentize_py_runtime.so.std::panicking::begin_panic_handler::_$u7b$$u7b$closure$u7d$$u7d$::he125d401eefa4f33 (wasm://wasm/libcomponentize_py_runtime.so-0052fcc2:wasm-function[1573]:0xb451a)
    at libcomponentize_py_runtime.so.std::sys::backtrace::__rust_end_short_backtrace::h31a9416a2c4ea1cb (wasm://wasm/libcomponentize_py_runtime.so-0052fcc2:wasm-function[1572]:0xb4442)

Simplified reproduction steps

1. Use wasmtime to run the final Wasm component file:
   wasmtime run world1-consumer_fromC++_importworld0-pvwxtgtmlk_fromPython.wasm
   Wasmtime prints:

[dbg] run: minimal begin
[dbg] py: open_temp begin
[dbg] py: handle.__init__ path=mem://h-1
[dbg] py: open_temp end path=mem://h-1
[dbg] run: before append
[dbg] py: handle.append begin path=mem://h-1 data=|x|
[dbg] py: handle.append end path=mem://h-1 size=3
[dbg] run: after append

2. Use jco to run the same final Wasm component file:
   jco run world1-consumer_fromC++_importworld0-pvwxtgtmlk_fromPython.wasm
   jco prints:

[dbg] run: minimal begin
[dbg] py: open_temp begin
[dbg] py: handle.__init__ path=mem://h-1
[dbg] py: open_temp end path=mem://h-1
[dbg] run: before append
AttributeError: '' object has no attribute 'append'

thread '<unnamed>' panicked at runtime/src/lib.rs:499:21:
Python function threw an unexpected exception
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
RuntimeError: unreachable
    at libc.so.abort (wasm://wasm/libc.so-001e65fe:wasm-function[458]:0x1041d)
    at wasm://wasm/02a675a6:wasm-function[306]:0xf8e8
    at libcomponentize_py_runtime.so.std::sys::pal::wasi::helpers::abort_internal::h118dde344a79086c (wasm://wasm/libcomponentize_py_runtime.so-0052fcc2:wasm-function[2193]:0xceb72)
    at libcomponentize_py_runtime.so.std::process::abort::h2738589d00d7233e (wasm://wasm/libcomponentize_py_runtime.so-0052fcc2:wasm-function[1645]:0xb87f6)
    at libcomponentize_py_runtime.so.__rustc::__rust_abort (wasm://wasm/libcomponentize_py_runtime.so-0052fcc2:wasm-function[2002]:0xc7330)
    at libcomponentize_py_runtime.so.__rustc::__rust_start_panic (wasm://wasm/libcomponentize_py_runtime.so-0052fcc2:wasm-function[2208]:0xcfc4c)
    at libcomponentize_py_runtime.so.__rustc::rust_panic (wasm://wasm/libcomponentize_py_runtime.so-0052fcc2:wasm-function[2035]:0xc8a1e)
    at libcomponentize_py_runtime.so.std::panicking::rust_panic_with_hook::h02d894de16d94192 (wasm://wasm/libcomponentize_py_runtime.so-0052fcc2:wasm-function[2034]:0xc899c)
    at libcomponentize_py_runtime.so.std::panicking::begin_panic_handler::_$u7b$$u7b$closure$u7d$$u7d$::he125d401eefa4f33 (wasm://wasm/libcomponentize_py_runtime.so-0052fcc2:wasm-function[1573]:0xb451a)
    at libcomponentize_py_runtime.so.std::sys::backtrace::__rust_end_short_backtrace::h31a9416a2c4ea1cb (wasm://wasm/libcomponentize_py_runtime.so-0052fcc2:wasm-function[1572]:0xb4442)

Result Analysis

The logic of this program is to create a Handle resource, and then call the append method on the resource.
jco prints different result from wasmtime.
The possible reason is that jco handles the resource type as a string type, so it indicates that the string type does not have an append method.

[vados-cosmonic]

Hi @xiaozzzZZzzz240 thanks for the report! Would you mind pointing to a repo for the reproduction with the source code and the WIT? You can also paste it inline in the issue if it's short enough.

[xiaozzzZZzzz240]

Hi @xiaozzzZZzzz240 thanks for the report! Would you mind pointing to a repo for the reproduction with the source code and the WIT? You can also paste it inline in the issue if it's short enough.

Thank you for your reply. I have uploaded all the files necessary for the reproduction steps, including the final generated Wasm component files.
The reproduction steps provides all the specific steps.
In addition, you can also directly follow the steps in the simplified reproduction steps to execute the final generated Wasm component files.
I have uploaded all the WIT files, high-level language programs, and generated Wasm component files.
All provided WIT files, high-level language source code, and Wasm component files are at the beginning of the issue.

[vados-cosmonic]

Ah, unfortunately -- downloading and opening zip files from the internet is somewhat high risk -- can you upload the code code for the reproduction to repo or paste the code?

[xiaozzzZZzzz240]

Ah, unfortunately -- downloading and opening zip files from the internet is somewhat high risk -- can you upload the code code for the reproduction to repo or paste the code?

Thanks for yout reply. All the files are in the repo: https://github.com/xiaozzzZZzzz240/jco_issue_1380

[vados-cosmonic]

Thanks so much for your patience here @xiaozzzZZzzz240 -- I'll get to this today and hopefully have a fix and test for you soon.

I will try to address all the individual issues at once, as they are likely related!