mirror of
https://github.com/bevyengine/bevy
synced 2024-12-26 04:53:07 +00:00
a0972c2b1b
When building Bevy using Bazel, you don't need a 'Cargo.toml'... except
Bevy requires it currently. Hopefully this can help illuminate the
requirement.
# Objective
I recently started exploring Bazel and Buck2. Currently Bazel has some
great advantages over Cargo for me and I was pretty happy to find that
things generally work quite well!
Once I added a target to my test project that depended on bevy but
didn't use Cargo, I didn't create a Cargo.toml file for it and things
appeared to work, but as soon as I went to derive from Component the
build failed with the cryptic error:
```
ERROR: /Users/photex/workspaces/personal/mb-rogue/scratch/BUILD:24:12: Compiling Rust bin hello_bevy (0 files) failed: (Exit 1): process_wrapper failed: error executing command (from target //scratch:hello_bevy) bazel-out/darwin_arm64-opt-exec-2B5CBBC6/bin/external/rules_rust/util/process_wrapper/process_wrapper --arg-file ... (remaining 312 arguments skipped)
error: proc-macro derive panicked
--> scratch/hello_bevy.rs:5:10
|
5 | #[derive(Component)]
| ^^^^^^^^^
|
= help: message: called `Result::unwrap()` on an `Err` value: Os { code: 2, kind: NotFound, message: "No such file or directory" }
error: proc-macro derive panicked
--> scratch/hello_bevy.rs:8:10
|
8 | #[derive(Component)]
| ^^^^^^^^^
|
= help: message: called `Result::unwrap()` on an `Err` value: Os { code: 2, kind: NotFound, message: "No such file or directory" }
```
## Solution
After poking around I realized that the proc macros in Bevy all use
bevy_macro_utils::BevyManifest, which was attempting to load a Cargo
manifest that doesn't exist.
This PR doesn't address the Cargo requirement (I'd love to see if there
was a way to support more than Cargo transparently), but it *does*
replace some calls to unwrap with expect and hopefully the error
messages will be more helpful for other folks like me hoping to pat down
a new trail:
```
ERROR: /Users/photex/workspaces/personal/mb-rogue/scratch/BUILD:23:12: Compiling Rust bin hello_bevy (0 files) failed: (Exit 1): process_wrapper failed: error executing command (from target //scratch:hello_bevy) bazel-out/darwin_arm64-opt-exec-2B5CBBC6/bin/external/rules_rust/util/process_wrapper/process_wrapper --arg-file ... (remaining 312 arguments skipped)
error: proc-macro derive panicked
--> scratch/hello_bevy.rs:5:10
|
5 | #[derive(Component)]
| ^^^^^^^^^
|
= help: message: Unable to read cargo manifest: /private/var/tmp/_bazel_photex/135f23dc56826c24d6c3c9f6b688b2fe/execroot/__main__/scratch/Cargo.toml: Os { code: 2, kind: NotFound, message: "No such file or directory" }
error: proc-macro derive panicked
--> scratch/hello_bevy.rs:8:10
|
8 | #[derive(Component)]
| ^^^^^^^^^
|
= help: message: Unable to read cargo manifest: /private/var/tmp/_bazel_photex/135f23dc56826c24d6c3c9f6b688b2fe/execroot/__main__/scratch/Cargo.toml: Os { code: 2, kind: NotFound, message: "No such file or directory" }
```
Co-authored-by: Chip Collier <chip.collier@avid.com>
|
||
|---|---|---|
| .. | ||
| bevy_a11y | ||
| bevy_animation | ||
| bevy_app | ||
| bevy_asset | ||
| bevy_audio | ||
| bevy_core | ||
| bevy_core_pipeline | ||
| bevy_derive | ||
| bevy_diagnostic | ||
| bevy_dylib | ||
| bevy_dynamic_plugin | ||
| bevy_ecs | ||
| bevy_ecs_compile_fail_tests | ||
| bevy_encase_derive | ||
| bevy_gilrs | ||
| bevy_gizmos | ||
| bevy_gltf | ||
| bevy_hierarchy | ||
| bevy_input | ||
| bevy_internal | ||
| bevy_log | ||
| bevy_macro_utils | ||
| bevy_macros_compile_fail_tests | ||
| bevy_math | ||
| bevy_mikktspace | ||
| bevy_pbr | ||
| bevy_ptr | ||
| bevy_reflect | ||
| bevy_reflect_compile_fail_tests | ||
| bevy_render | ||
| bevy_scene | ||
| bevy_sprite | ||
| bevy_tasks | ||
| bevy_text | ||
| bevy_time | ||
| bevy_transform | ||
| bevy_ui | ||
| bevy_utils | ||
| bevy_window | ||
| bevy_winit | ||