Feature Request: add suggestion for similarly named features with `cargo add`

[Jujumba]

Problem

When adding a crate with certain features and misspelling one of them, cargo doesn't suggest features with similar names. This may be confusing if a crate has lots of features. For example:

$ cargo add axum_extra --features typed-headers  # The actual feature is `typed-header`, see the last row of disabled features
    Updating crates.io index
warning: translating `axum_extra` to `axum-extra`
      Adding axum-extra v0.10.1 to dependencies
error: unrecognized feature for crate axum-extra: typed-headers
disabled features:
    __private_docs, async-read-body, async-stream, attachment, cookie
    cookie-key-expansion, cookie-private, cookie-signed, erased-json
    error-response, file-stream, form, json-deserializer, json-lines, multipart
    protobuf, query, scheme, typed-header, typed-routing
enabled features:
    tracing

Proposed Solution

Instead of just listing all feature flags, cargo may additionally search for similarly named features and suggest them, so that it looks like the following:

$ cargo add axum_extra --features typed-headers
    Updating crates.io index
warning: translating `axum_extra` to `axum-extra`
      Adding axum-extra v0.10.1 to dependencies
error: unrecognized feature for crate axum-extra: typed-headers
help: a feature with a similar name exists: `typed-header`
disabled features:
    __private_docs, async-read-body, async-stream, attachment, cookie
    cookie-key-expansion, cookie-private, cookie-signed, erased-json
    error-response, file-stream, form, json-deserializer, json-lines, multipart
    protobuf, query, scheme, typed-header, typed-routing
enabled features:
    tracing

The help output here is worded the same way the compiler does

Notes

No response

[Jujumba]

I'd also love to work on this if the issue gets accepted. Thanks!

[epage]

Good idea!

The error is at https://github.com/rust-lang/cargo/blob/master/src/cargo/ops/cargo_add/mod.rs#L161

The helper for generating the message is at https://github.com/rust-lang/cargo/blob/master/src/cargo/util/edit_distance.rs#L112

[epage]

Also, be sure to read https://doc.crates.io/contrib/process/working-on-cargo.html#submitting-a-pull-request

[Jujumba]

@rustbot claim

[Jujumba]

The helper for generating the message is at https://github.com/rust-lang/cargo/blob/master/src/cargo/util/edit_distance.rs#L112

Do you think that edit_distance::closest_msg is appropriate? I think edit_distance::closest is a better choice since there may be several misspelled features, and adding a new line for each suggestion is a little lengthy.

[epage]

My first thought is "what would rustc do?". In general, we are moving towards better aligning ourselves with rustc.

I feel like the scale for the number of misspelled features within one invocation is likely small (0-2) that it shouldn't be much of a problem in the common cases.

[Jujumba]

My first thought is "what would rustc do?". In general, we are moving towards better aligning ourselves with rustc.

I feel like the scale for the number of misspelled features within one invocation is likely small (0-2) that it shouldn't be much of a problem in the common cases.

Alright, thanks!

I've implemented the feature though one thing lacks: coloring of the help: ... section. How could I get the help part of the message colored?

[epage]

Currently, we've not been doing that. When the next version of annotate-snippets is out, I'd like to look at switching all of our error reporting to that.