Integration with bevy_ecs - linker failure pthread_setcancelstate is not implemented

[mrchantey]

I'm looking to use bevy_ecs with esp-idf but am getting linker errors when I add the bevy_ecs dependency. I'm using the esp-idf-template and have tried with both Windows and the dev container.

The errors are all along the lines of pthread_attr_init is not implemented and will always fail

bevy_ecs is the lightweight ecs architecture that drives the bevy engine, I thought it might 'just work' with esp-idf because it officially supports wasm which is also a restricted environment.

my setup

default std esp-idf-template
device: esp32-c3
ESP_IDF_VERSION = "v5.1.1"

[dependencies]
bevy_ecs = { version = "0.12.1" }
esp-idf-svc = { version = "0.47.3", default-features = false }

main.rs

use bevy_ecs::prelude::World;

fn main() {
	esp_idf_hal::sys::link_patches();
	let _world = World::new();
}

error

error: linking with `ldproxy` failed: exit code: 1

  = note: [ldproxy] Running ldproxy
          Error: Linker SOME_PATH/.rustup/toolchains/esp/riscv32-esp-elf/esp-12.2.0_20230208/riscv32-esp-elf/bin/riscv32-esp-elf-gcc.exe failed: exit code: 1
          STDERR OUTPUT:

SOME_PATH/.embuild/espressif/esp-idf/v5.1.1/components/pthread/pthread.c:769: warning: pthread_attr_init is not implemented and will always fail

SOME_PATH/riscv32-esp-elf/bin/ld.exe: SOME_PATH/riscv32-esp-elf/lib/rv32imc_zicsr_zifencei/ilp32/no-rtti\libnosys.a(pthread.o): in function `pthread_attr_init':
/builds/idf/crosstool-NG/.build/HOST-x86_64-w64-mingw32/riscv32-esp-elf/src/newlib/libgloss/libnosys/pthread.c:102: multiple definition of `pthread_attr_init'; esp-idf\pthread\libpthread.a(pthread.c.obj): 
SOME_PATH/.embuild/espressif/esp-idf/v5.1.1/components/pthread/pthread.c:756: first defined here

... The same for lots of other similar definitions, ie pthread_attr_setdetachstate

[MabezDev]

The pthread_attr_* functions in newlib are not implemented in the espidf newlib port. It's probably quite a lot of work to add them, maybe a better idea would be to find out why bevy_ecs depends on these functions, and see if it can be cfg'd away for target_os = "espidf". I'm not at all familiar with bevy, so I probably cannot help here, sorry :(.

[MabezDev]

Maybe a start would be to disable the multithreading feature: https://github.com/bevyengine/bevy/blob/c4e479a2d4f2ca1d7ce2637e4da1a4bb5cbed133/crates/bevy_ecs/Cargo.toml#L14

[MabezDev]

Huh, I guess I might have found how wasm32 works: https://github.com/bevyengine/bevy/blob/c4e479a2d4f2ca1d7ce2637e4da1a4bb5cbed133/crates/bevy_ecs/src/query/par_iter.rs#L112-L125. On wasm32 it defaults to single thread operation, maybe they would accept a PR which adds target_os = "espidf" too.

[mrchantey]

Thanks yeah looks like it should also go for that operation when multi-threading is disabled, but still get the error even with super explicit feature disabling:

[dependencies]
bevy_ecs = { version = "0.12.1", default-features = false, features = [] }
bevy_tasks = { version = "0.12.1", default-features = false, features = [] }

[mrchantey]

Ok it looks like this is a duplicate of esp-idf-template/178

WORKAROUND: Remove -C default-linker-libraries from .cargo/config.toml.

^^ I can confirm this was the solution for my issue too.