RFC30: add Serde Decorator to RustClientCodegenPlugin

[thomas-k-cameron]

Motivation and Context

Add new plugin to RustClientCodegenPlugin

• This is a child PR of RFC30 #2615
• This PR should be able to pass tests once Add serde support to document type. #2616 is merged.

No breaking changes are introduced.

Description

The new plugin adds serde-* features to generated sdk's Cargo.toml.

Users can enable aws-smithy-type's serde features by passing arguments.

Testing

NA

Checklist

NA

---

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[thomas-k-cameron]

NOTE:
Error comes from the lack of feature-gate on published crates.

    Updating crates.io index
error: failed to select a version for `aws-smithy-types`.
    ... required by package `aws-sdk-sso v0.0.0-local (/home/build/workspace/aws-sdk-smoketest/sdk/sso)`
    ... which satisfies path dependency `aws-sdk-sso` of package `aws-config v0.0.0-smithy-rs-head (/home/build/workspace/aws-sdk-smoketest/sdk/aws-config)`
versions that meet the requirements `^0.0.0-smithy-rs-head` are: 0.0.0-smithy-rs-head

the package `aws-sdk-sso` depends on `aws-smithy-types`, with features: `serde-deserialize` but `aws-smithy-types` does not have these features.

[thomas-k-cameron]

Oh, it seems to be working now!

[jdisanti]

Would be good to also hook into the ModuleDocSection.ServiceDocs, or even add a new ModuleDocSection.Features, so that these features can be described in the docs. That way, the documentation can inform on the --cfg aws_sdk_unstable requirement. This would require registering a LibRsCustomization, so override fun libRsCustomizations(...).

There's an example here that adds information to the "Crate Organization" documentation section: https://github.com/awslabs/smithy-rs/blob/2f60a5e0904037ec5237c080c61817617b9d8c06/codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/customizations/ClientCustomizations.kt#L19

[thomas-k-cameron]

I added this function but it seems like there are no changes to the generated code.

Is there anything else that I'm supposed to add?

[thomas-k-cameron]

Here is the text that is going to be included on the lib.rs docs.
I tried to use the libRsCustomization but somehow it didn't work.

[jdisanti]

What did it look like when it was overriding libRsCustomization?

[thomas-k-cameron]

I was able to make it work!

It looks like this.

I tried to put two hash marks,
e.g.

//! # Enabling Unstable Features
//! ## How to enable `Serialize` and `Deserialize`

but I couldn't make it work.

[thomas-k-cameron]

I tried to find the commit that didn't work, but it's lost somewhere in the commit history.