Remove attributes annotation of Builder struct

[edisongustavo]

The struct created for a Builder should not have attributes because these structs only derive from Debug, PartialEq, Clone and Default. None of these support attributes.

This becomes a problem if a plugin tries to add attributes to the metadata field to configure the generated code for the struct. In this case, the attributes will also be added to the Builder struct; which is wrong.

Motivation and Context

I'm customizing client code generation by overriding the method:

override fun symbolProvider(base: RustSymbolProvider): RustSymbolProvider

I override the symbol.expectRustMetadata().additionalAttributes value and add extra values there. The generated code adds the correct attributes for the struct, however, it also adds these attributes to the Builder.

The Builder is restricted to deriving from Debug, PartialEq, Clone and Default (see code).

I believe this change was added by mistake in #2222.

Description

To solve the issue, I simply remove the offending line.

Testing

I don't expect any existing code to break, given that this is a bug. It only manifests when someone is customizing the generated code.

Checklist

• I have updated CHANGELOG.next.toml if I made changes to the smithy-rs codegen or runtime crates
• I have updated CHANGELOG.next.toml if I made changes to the AWS SDK, generated SDK code, or SDK runtime crates

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[github-actions]

A new generated diff is ready to view.

• AWS SDK (ignoring whitespace)
• Client Test (ignoring whitespace)
• No codegen difference in the Server Test
• No codegen difference in the Server Test Python
• No codegen difference in the Server Test Typescript

A new doc preview is ready to view.

[edisongustavo]

Ok, I see that we actually need Builders to have the non_exhaustive attribute. I'll work on fixing this.

[david-perez]

This LGTM but we'd want this change too to apply to the server. Make the change to these files too:

• ServerBuilderGenerator
• ServerBuilderGeneratorWithoutPublicConstrainedTypes

Bonus points if you make things DRYer and/or document the motivation for this change with either a comment or a small test.

[edisongustavo]

Thanks @david-perez! I will change those files too, as you requested.

[edisongustavo]

Hello @david-perez , I have added the tests as you requested, to both client and server generators.

Notice that I didn't need to make any changes to the server classes because they don't have the same bug as the client.

Please let me know if you'd like me to do anything else in this PR.

[david-perez]

Thanks for the tests!

[edisongustavo]

Hello, how could we expedite this to be merged and available in the next release?

[edisongustavo]

I see some linting checks failed. I'll resolve these and update the branch

[edisongustavo]

I'm sorry I didn't see the ./gradlew ktlint --format option. I can run everything locally now, so the next set of tests should pass.

[edisongustavo]

Hello, the failing check is ci / Ask maintainer to run the PR bot and canary workflows.