How to describe dependencies on local packages with relative path

[NewGyu]

Hello developers,

I'm trying to understand Component Model with cargo-component. To that end I have tried to create a simple example, but I have the following error and would like to discuss it if you allow me to do it here.

$ cargo component build --release
error: failed to create a target world for package `comp2` (/workspaces/wasm-component-example/comp2/Cargo.toml)

Caused by:
    0: failed to decode component dependency `newgyu:comp1`
    1: dependency is not a WebAssembly component

cargo-component version is here.

 $ cargo component --version
cargo-component-component 0.1.0 (6af088a 2023-08-16 wasi:2750b73)

My example and what I expect

https://github.com/NewGyu/wasm-component-example

There are two packages, then each package has a world.

• newgyu:comp1/random-generator
  • rand func is exported.
• newgyu:comp2/hello
  • hello-world func is exported, and that depends on rand func that is provided by newgyu:comp1.

Directory structures

$ tree -L 2.
.
├── comp1
│   ├── Cargo.toml
│   ├── src
│   │      └── lib.rs
│   └── wit
│           └── world.wit
├── comp2
│   ├── Cargo.toml
│   ├── src
│   │      └── lib.rs
│   └── wit
│           └── world.wit

Code

comp2

comp2 is specifying a dependency on comp1 as local package reference.

[package]
name = "comp2"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
cargo-component-bindings = { git = "https://github.com/bytecodealliance/cargo-component" }

[lib]
crate-type = ["cdylib"]

[package.metadata.component]
package = "newgyu:comp2"

[package.metadata.component.target]
path = "wit"

[package.metadata.component.dependencies]
"newgyu:comp1" = { path = "../comp1/wit/world.wit" }

comp1

comp1 could be built with cargo component build --release. The followings have been built.

• target/bindings/comp1/target.wasm
• target/bindings/comp1/world
• target/wasm32-wasi/release/comp1.wasm

[package]
name = "comp1"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
cargo-component-bindings = { git = "https://github.com/bytecodealliance/cargo-component" }

[lib]
crate-type = ["cdylib"]

[package.metadata.component]
package = "newgyu:comp1"

[package.metadata.component.target]
path = "wit"
world = "random-generator"

[package.metadata.component.dependencies]

Points I would like to ask about

• Is it correct tow to describe dependencies on local packages with relative path ?
• Is the dependency type handled as Wit when described as above ?
  • Why does into_component_world respond error?
  • Should I explicitly specify Wasm as the dependency type? How to specify that in Cargo.toml?

https://github.com/bytecodealliance/cargo-component/blob/3f36696db9c39785886b0766b2b81f83cbc3d29e/crates/core/src/registry.rs#L394-L402