improving the 0.29.0 JsonReader error message for the polars-core crate when required feature flags are missing during schema inference

[jay-johnson]

Hello!

Thanks for this awesome repo and the great community!

This pr shows the user what may be missing within their Cargo.toml with a helpful suggestion after hitting errors with the new 0.29.0 JsonReader support. Without the additional polars-core feature flags (mentioned in the logged error message), the new 0.29.0 infer schema support crashes rust binaries that are not compiled with these polars-core feature flags on these lines:

• https://github.com/pola-rs/polars/blame/6334057879948d372a2bc718d4af0223c216edc7/polars/polars-core/src/datatypes/field.rs#L142
• https://github.com/pola-rs/polars/pull/8411/files#diff-586ff9ed1f826ead771508d6aacd9a25988747372a47eff779390f05f54ec7f2R215

Without the logged feature flags (I think only dtype-struct is actually required now), I was seeing this error with my previously-stable 0.28.0 JsonReader schema inference:

thread 'main' panicked at 'Arrow datatype Struct([Field { name: "date", data_type: Int64, is_nullable: true, metadata: {} }, Field { name: "date_utc_str", data_type: Utf8, is_nullable: true, metadata: {} }, Field { name: "ds", data_type: Utf8, is_nullable: true, metadata: {} }, Field { name: "q.last", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "q.change", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "q.v", data_type: Int64, is_nullable: true, metadata: {} }, Field { name: "q.o", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "q.h", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "q.l", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "q.c", data_type: Int64, is_nullable: true, metadata: {} }, Field { name: "q.b", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "q.a", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "q.chg_p", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "q.avg_vlm", data_type: Int64, is_nullable: true, metadata: {} }, Field { name: "q.last_vlm", data_type: Int64, is_nullable: true, metadata: {} }, Field { name: "q.trade_date", data_type: Int64, is_nullable: true, metadata: {} }, Field { name: "q.pc", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "q.w52h", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "q.w52l", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "q.b_s", data_type: Int64, is_nullable: true, metadata: {} }, Field { name: "q.b_date", data_type: Int64, is_nullable: true, metadata: {} }, Field { name: "q.a_s", data_type: Int64, is_nullable: true, metadata: {} }, Field { name: "q.a_date", data_type: Int64, is_nullable: true, metadata: {} }, Field { name: "atm_d", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "strike", data_type: Int64, is_nullable: true, metadata: {} }, Field { name: "change", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "volume", data_type: Int64, is_nullable: true, metadata: {} }, Field { name: "open", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "high", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "low", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "close", data_type: Int64, is_nullable: true, metadata: {} }, Field { name: "bid", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "ask", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "last", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "cp", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "a_vol", data_type: Int64, is_nullable: true, metadata: {} }, Field { name: "l_vol", data_type: Int64, is_nullable: true, metadata: {} }, Field { name: "pc", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "bid_s", data_type: Int64, is_nullable: true, metadata: {} }, Field { name: "ask_s", data_type: Int64, is_nullable: true, metadata: {} }, Field { name: "oi", data_type: Int64, is_nullable: true, metadata: {} }, Field { name: "ct_size", data_type: Int64, is_nullable: true, metadata: {} }, Field { name: "expdate", data_type: Utf8, is_nullable: true, metadata: {} }, Field { name: "ot", data_type: Utf8, is_nullable: true, metadata: {} }, Field { name: "delta", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "gamma", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "theta", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "vega", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "rho", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "phi", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "bid_iv", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "mid_iv", data_type: Float64, is_nullable: true, metadata: {} }, Field { name: "ask_iv", data_type: Float64, is_nullable: true, metadata: {} }]) not supported by Polars. You probably need to activate that data-type feature.', /home/jay/.cargo/registry/src/github.com-1ecc6299db9ec823/polars-core-0.29.0/src/datatypes/field.rs:156:19 stack backtrace: 0: rust_begin_unwind at /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/library/std/src/panicking.rs:575:5 1: core::panicking::panic_fmt at /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/library/core/src/panicking.rs:64:14 2: polars_core::datatypes::field::<impl core::convert::From<&arrow2::datatypes::DataType> for polars_core::datatypes::dtype::DataType>::from at /home/jay/.cargo/registry/src/github.com-1ecc6299db9ec823/polars-core-0.29.0/src/datatypes/field.rs:156:19 3: <polars_io::json::JsonReader<R> as polars_io::SerReader<R>>::finish::{{closure}}::{{closure}} at /home/jay/.cargo/registry/src/github.com-1ecc6299db9ec823/polars-io-0.29.0/src/json.rs:215:43 4: core::result::Result<T,E>::map at /rustc/2c8cc343237b8f7d5a3c3703e3a87f2eb2c54a74/library/core/src/result.rs:774:25 5: <polars_io::json::JsonReader<R> as polars_io::SerReader<R>>::finish::{{closure}} at /home/jay/.cargo/registry/src/github.com-1ecc6299db9ec823/polars-io-0.29.0/src/json.rs:213:29

Thanks again for this project!