Be able to enable --features / --all-features / --no-default-features

[repi]

Would it be possible to add support for the Cargo --features / --all-features / --no-default-features options? Pipe them through to the underlying Cargo invocation.

We have multiple crates where we are both interested in the public API with --all-features enabled and also some where one wants to check for specific --features.

For example our puffin crate has a mutually exclusive features (not ideal) and fails to analyse:

$ cargo public-api --manifest-path ./puffin/Cargo.toml
    Checking once_cell v1.9.0
    Checking byteorder v1.4.3
 Documenting puffin v0.12.1 (/Users/repi/git/embark/puffin/puffin)
error: Either feature zstd or ruzstd must be enabled
   --> puffin/src/frame_data.rs:491:1
    |
491 | compile_error!("Either feature zstd or ruzstd must be enabled");
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: Compilation failed, aborting rustdoc

error: could not document `puffin`

Caused by:
  process didn't exit successfully: `rustdoc --edition=2018 --crate-type lib --crate-name puffin puffin/src/lib.rs -o /Users/repi/git/embark/puffin/target/doc --cfg 'feature="default"' --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat -Z unstable-options --output-format json --cap-lints warn -C metadata=00aac93aa62b9ad4 -L dependency=/Users/repi/git/embark/puffin/target/debug/deps --extern byteorder=/Users/repi/git/embark/puffin/target/debug/deps/libbyteorder-922739cc82a0baa2.rmeta --extern once_cell=/Users/repi/git/embark/puffin/target/debug/deps/libonce_cell-b334803526b5c51d.rmeta --crate-version 0.12.1` (exit status: 1)
Error: Failed to build rustdoc JSON. Stderr: See above

[Enselic]

Thank you for the feature request! It indeed makes a lot of sense to be able to select features. I have been wondering how long it would take before someone requested that ;)

I think the way forward is to add features of the appropriate type to rustdoc_json::BuildOptions found in this git. Should be pretty straightforward, so also setting as "good first issue".

[Emilgardis]

I'm trying to implement this, and I'm wondering if the way to go is actually doing something like this

cargo public-api -- <my_cargo_rustdoc_flags> -- <my_rustdoc_flags>

ofc, that makes it possible to have duplicate flags but I think that's fine. BuildOptions could still take it explicitly

[Emilgardis]

That would mean to enable a feature for your crate, you'd do

cargo public-api -- --features myfeature,otherfeature