Enable All Except A Specific Feature From CLI

[tustvold]

Problem

Within the arrow repository we have a workspace with a moderate number of library crates, each with their own features. In CI we would like to enable all features to ensure we run all the tests, unfortunately one of the features "simd" is only available on nightly compilers.

This leads to an error prone approach of having to list every feature apart from the one that can't be run on stable

cargo test -p arrow --features=force_validate,prettyprint,ipc_compression,ffi,dyn_cmp_dict,dyn_arith_dict,chrono-tz

It is not uncommon to accidentally miss a feature out from this list, especially as this has to be duplicated not only for cargo test but also the various cargo check and cargo clippy commands.

Proposed Solution

I would like to be able to use something like

cargo test --all-features-except simd

Which would enable all features except those listed

Notes

No response

[weihanglo]

Thank you for the report. I believe this is covered by #3126. People are brewing innovative ideas and syntaxes there. Any further discussion is suggested to happen in that thread. Closing now. Thanks again!

[tustvold]

#3126 refers to disabling features which isn't what I'm asking for, and has complex semantics being debated on the issue. I'm instead asking for a way to enable everything except a specific feature, i.e. purely additive not subtractive, and purely constrained to the CLI?

[weihanglo]

There are more comments talking about features=-foo syntax. For instance, --all-features --features -legacy-compat covers the usage of proposed --all-features-except option. I feel like we should consider them as a whole to avoid introducing too many new flags serving only few special purposes.

[tustvold]

Fair enough, I guess I just hoped that by reducing the scope to something small and uncontroversial we could get something in, as opposed to waiting on something that has been being discussed for 6 years now... Perfect is the enemy of good and all that