[Fred1155]

Motivations

In the Smithy path, the intermediate model had no waiters, so a client generated from Smithy had no waiter classes or waiter() method. This PR translates Smithy's @waitable trait, following the same approach as the paginator PR #7463.

@waitable can't express three things waiters-2.json has:

• Attempt limit: every C2J waiter has maxAttempts; Smithy waiters have none.
• HTTP status matcher: C2J can match on a response status code; Smithy can't.
• C2J-only waiters: some waiters in waiters-2.json have no @waitable counterpart.

For these, a new codegen trait, software.amazon.awssdk.codegen#waiterOverrides, sits on the operation, keyed by waiter name. Each entry is one of:

• maxAttempts alone: translate the @waitable waiter with this limit.
• maxAttempts, delay and acceptors: use this waiters-2.json waiter instead.
• skip: true: generate no waiter.

Like paginatorOverride, it is applied through smithy-build.json, so model.json is not edited.

Modifications

1. waiterOverrides trait: defined in aws-sdk-java-codegen-traits.smithy, with the class WaiterOverridesTrait registered as a TraitService. An invalid entry fails when the trait is loaded.
2. AddSmithyWaiters: builds the waiter map, keyed by waiter name.

   • A skip entry drops the waiter; a full entry is used as written; otherwise the @waitable waiter is translated.

   • Delay is minDelay (Smithy's default of 2 when absent). maxAttempts comes from the override. maxDelay, documentation and deprecation are dropped.

   • Matchers map as follows:

     Smithy matcher	C2J acceptor
     success: true / success: false	error, expected false / true
     errorType	error, type copied as written
     output with stringEquals / booleanEquals	path
     output with allStringEquals / anyStringEquals	pathAll / pathAny
     inputOutput, or an errorType with a shape ID	Fails: the Java waiter runtime can't evaluate it

   • Generation fails, with a message naming the waiter, when a waiter has no maxAttempts or a maxAttempts-only entry has no @waitable waiter.

3. SmithyIntermediateModelBuilder: passes the waiter map into the intermediate model.
4. codegen/pom.xml: smithy-waiters moves from runtime to compile scope, because AddSmithyWaiters uses its classes.

Waiters are ordered by name, so some clients list waiter methods in a different order than on C2J. Behavior is the same.

Not in this PR:

• Writing the overrides: generating waiterOverrides entries from waiters-2.json into smithy-build.json belongs with the smithy-build.json generator, together with paginatorOverride.

Testing

mvn -o test -pl :codegen,:codegen-maven-plugin passed.

New and updated tests:

• AddSmithyWaitersTest: each matcher's translation, the default minDelay, a full override replacing a @waitable waiter, a full override without one, skip, and each failure case.
• SmithyCodegenTraitsTest: the trait loads through TraitService, invalid entries are rejected with their messages, and the trait is rejected on a non-operation shape.
• AwsSdkJavaCodegenPluginTest: a @waitable waiter and an overridden waiter generate waiter classes through smithy-build, and a @waitable waiter without maxAttempts fails.
• SmithyBuildGeneratorTest (codegen-maven-plugin): the real-model test model now carries a waiterOverrides entry for its waiter, because a @waitable waiter without one fails by design.

Manual one-time check: an all-services intermediate model parity run, with the overrides written from each service's waiters-2.json, found no waiter differences between the Smithy and C2J paths for any compared client.

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Checklist

• I have read the CONTRIBUTING document
• Local run of mvn install succeeds
• My code follows the code style of this project
• My change requires a change to the Javadoc documentation
• I have updated the Javadoc documentation accordingly
• I have added tests to cover my changes
• All new and existing tests passed
• I have added a changelog entry. Adding a new entry must be accomplished by running the scripts/new-change script and following the instructions. Commit the new file created by the script in .changes/next-release with your changes.
• My change is to implement 1.11 parity feature and I have updated LaunchChangelog

License

• I confirm that this pull request can be released under the Apache 2 license

[jencymaryjoseph]

Do we have tests covering duplicate waiter names across operations, unsupported/unknown smithy matchers and verification of their exception messages?

[Fred1155]

The unsupported matchers have tests that check their messages. We have no tests for duplicate-name and unknown matcher, since Smithy rejects it during model validation.

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