[BUG - HOLONIX] failing to build zomes on latest 0_2 holonix about holochain

[mattyg]

Here's a minimal reproduction: https://github.com/mattyg/bug-reproduction-nix-zome-build

Run npm run build:happ and it fails to build on linux x64

Sorry I meant latest 0_2 holonix

Looks like mio is coming in from tokio, which I think is coming in from including holochain test_utils as a dev dependency

[mattyg]

Looking at the docs, Cargo makes no promise not to build dev-dependencies with the release flag, it just affects optimisation. I find that incredibly strange but that's what it currently does I think https://doc.rust-lang.org/cargo/commands/cargo-build.html#examples

Holochain wasmer does this to avoid pulling deps into a wasm build, maybe that's a possible solution here? https://github.com/holochain/holochain-wasmer/blob/develop/crates/common/Cargo.toml#L20C57-L20C57

huh bizarre okay thanks I'll try that

though in the rust book it does say dev-dependencies are not compiled for building:

Dev-dependencies are not used when compiling a package for building, but are used for compiling tests, examples, and benchmarks.
https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#development-dependencies

[mattyg]

I wonder if it makes sense to actually build the scaffolded web-app in test to confirm all the build tooling is as expected in holonix:

holochain/holonix/test/scaffolding.bats

Line 19 in 6dbf9a2

@test "expected scaffold an example to succeed" {

[steveej]

can you share the steps you took to scaffold the happ or alternatively share a git repository?

at first sight i'm confused why mio is pulled in as a dependency for the wasm build, as i understand mio uses system API that is not provided by the wasm32-unknown-unknown target.

[ThetaSinner]

Looking at the docs, Cargo makes no promise not to build dev-dependencies with the release flag, it just affects optimisation. I find that incredibly strange but that's what it currently does I think https://doc.rust-lang.org/cargo/commands/cargo-build.html#examples

Holochain wasmer does this to avoid pulling deps into a wasm build, maybe that's a possible solution here? https://github.com/holochain/holochain-wasmer/blob/develop/crates/common/Cargo.toml#L20C57-L20C57

[ThetaSinner]

Interesting, yes they say different things on different doc pages. The page dedicated to dev-dependencies just says "These dependencies are not propagated to other packages which depend on this package." - https://doc.rust-lang.org/rust-by-example/testing/dev_dependencies.html

I actually wonder though whether this should be a dependency of the coordinator. It would be nice to have the tests live alongside the zome but the tests are actually going to want to depend on the compiled wasm output so it'll be two steps to run them anyway. So it might make sense to have a tests project... It feels a bit untidy to have to do that though, I'd rather it was a choice.

The other possibility is to raise this for clarification with the Rust project because this behavior certainly isn't desirable. It'd be worth checking if this happens in a project that isn't in a workspace before going to them, but otherwise this does seem like at very least a documentation gap.

[mattyg]

Closing since it's definitely not a holonix issue -- I think it's related to some limitations in cargo workspaces.

[mattyg]

I just needed to specify resolver = "2" in the workspace manifest. Added a PR to scaffolder here: holochain/scaffolding#132