Codegen does not implement @clientDefaultValue decorator

[RickWinter]

Summary

The Rust emitter does not implement the @clientDefaultValue TypeSpec decorator. Parameters and model properties annotated with @clientDefaultValue are generated as plain Option<T> fields with no default values applied.

Expected behavior

• Options structs: Fields with @clientDefaultValue should have their defaults pre-populated in the Default trait implementation.
• Model structs: Fields with @clientDefaultValue (e.g. retry, tier, timeout on ModelWithDefaultValues) should be pre-populated with their default values in the Default impl.
• Client methods: When the user does not provide a value, the generated client should automatically apply the declared default before sending the request.

Actual behavior

All @clientDefaultValue fields are generated as Option<T> defaulting to None. Callers must manually provide the default values.

Affected crate

test/spector/azure/client-generator-core/client-default-value

Test impact

Several integration tests in this crate have been disabled with #[ignore] because they were working around this limitation by manually providing default values. See the test file for details.

[jhendrixMSFT]

The interesting case is for required method parameters. A client-side default means they're effectively optional.

[jhendrixMSFT]

Our POR is to do nothing, leaving such params as required. However, it might be useful to emit this info as a doc comment.

/// If you don't know what to pass here, pass {clientDefaultValue}