[Vertex AI] Add anyOf support to Schema

[andrewheard]

Added support for Schema.anyOf(...), which is a Schema representing a value that must conform to any (one or more) of the provided sub-schemas. See #14647 for context.

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[gemini-code-assist]

Code Review

This pull request introduces support for the anyOf schema, enhancing the flexibility of data generation with Vertex AI. The changes include modifications to the DataType enum, Schema class, and the addition of a new integration test. Overall, the implementation appears well-structured and addresses the intended functionality.

Summary of Findings

• Documentation Clarity: The documentation for the anyOf schema could be enhanced to explicitly state the behavior when multiple sub-schemas are valid against the generated data. Clarifying the selection process or prioritization would improve user understanding.
• Error Handling: The anyOf function includes a fatalError if the schemas array is empty. While this prevents invalid configurations, consider providing a more graceful error handling mechanism, such as throwing an exception, to allow for more flexible error management in client code.
• Test Coverage: The integration test covers the basic functionality of the anyOf schema. Expanding the test suite to include edge cases, such as nested anyOf schemas or combinations with other schema constraints, would improve the robustness of the implementation.

Merge Readiness

The pull request is well-structured and introduces a valuable feature. However, addressing the documentation clarity and error handling concerns would enhance the overall quality and usability of the code. While the integration test provides a good starting point, expanding the test suite to cover edge cases would further improve the robustness of the implementation. I am unable to approve this pull request, and recommend that another reviewer does so after the suggestions have been addressed. I recommend that the pull request not be merged until the high severity issues are addressed (at a minimum).

[paulb777]

Still test failures to resolve.

[paulb777]

Great set of unit tests. Thanks!