Running examples with required features should be easier #15912
Description
Problem
When attempting to run an example that requires additional features, I encounter an error message that looks like:
alice@pop-os:~/Documents/bevy$ cargo run --example solari
error: target `solari` in package `bevy` requires the features: `bevy_solari`, `https`
Consider enabling them by passing, e.g., `--features="bevy_solari https"`I then copy-paste this incantation into the terminal:
alice@pop-os:~/Documents/bevy$ cargo run --example solari --features="bevy_solari https"and it now works!
This is a clear and helpful error message, but the process feels needlessly convoluted: cargo already knows what incantation I clearly intended to call!
Proposed Solution
Option 1: Prompt to rerun
Add a y/n prompt when outputting this error message, asking if the user would like to rerun the example with the corresponding features enabled. If yes, do that.
Option 2: --required-features flag
Create a command line flag for cargo run --example --required-features that automatically enables all required features for the example.
Option 3: Quietly do the right thing by default
Always run examples with the required features, logging that such-and-such features were required.
Add a special opt-out if necessary, like --no-required-features.
Notes
As a user, I think that Option 1 is best, followed by Option 3.
- Option 1: clear, explicit, not too onerous, no magic
- Option 2: slightly easier to type and less annoying, but why is this not the default?
- Option 3: very smooth and low friction, but clever in a way that makes me a bit nervous
That said, I am unsure if Cargo supports prompts: Option 1 may not be feasible to implement.