Support Error in no_std environments #268
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The `Error` derive can be made to work well for the most part in `no_std` environments by enabling `#![feature(error_in_core)]`. This changes the `Error` derive slightly to import `Error` and related traits from core, when the `std` feature is disabled. Fixes #261
impl/src/error.rs
Outdated
| @@ -18,7 +18,7 @@ pub fn expand( | |||
| let state = State::with_attr_params( | |||
| input, | |||
| trait_name, | |||
| quote! { ::std::error }, | |||
| quote!{ ::derive_more::__private::Error }, | |||
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@JelteF how about just ::derive_more::Error?
We can bring the trait in scope together with the macro. This may be handy for much cases. And we can do this for all the traits (in a separate PR, surely).
Still, if someone needs only a macro, we could have done it like use derive_more::macro::Error.
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We can bring the trait in scope together with the macro. This may be handy for much cases. And we can do this for all the traits (in a separate PR, surely).
Yeah, I think that's probably a good idea. Because of this change I'm working on adding the following line to all our tests:
#![cfg_attr(not(feature = "std"), no_std)]
And automatically importing the traits, possibly from alloc would be quite useful.
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I'll leave it as __private here and we can make it public in the follow up PR where we do this for all traits.
| @@ -128,7 +132,7 @@ jobs: | |||
| go install github.com/pelletier/go-toml/cmd/tomljson@latest | |||
| echo "$HOME/go/bin" >> $GITHUB_PATH | |||
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| - run: ci/test_all_features.sh | |||
| - run: ci/test_all_features.sh ${{ matrix.std }} | |||
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@JelteF I think here will be enough just to run tests 2 times sequentially, rather than matrix over the input parameter.
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I think it's quite nice to see if both no_std and std are broken with a quick glance at the job output. Also it would double our CI time, since it would be the longest running job by ~2x the previous one. So I changed this back to use a matrix. I did make the matrix a bit more descriptive though, so that the job output is clearer.
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@JelteF you should edit branch protection rules, because now CI awaits test features job to complete, while we have test features (std) and test features (no_std) now only.
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Done. If you approve the PR it should merge automatically.
Resolves #261
Synopsis
The
Errorderive can be made to work well for the most part inno_stdenvironments by enabling#![feature(error_in_core)]. Thischanges the
Errorderive slightly to importErrorand relatedtraits from core, when the
stdfeature is disabled.In passing this also fixes actually running the nightly error tests. They were not actually run anymore because there was no
build.rsfile in the root of the repo, only in theimplpackage. So thenightlyconfig was not available in tests.Checklist