API based Schema Migration behind experimental flag.

[itsrakhil]

This adds the fdcapimigration experimental flag to src/experiments.ts and conditionally executes schema migration commands via the Firebase Data Connect (FDC) API Backend when enabled.

[gemini-code-assist]

Code Review

This pull request introduces the fdcapimigration experiment, allowing SQL schema migrations to be delegated to the FDC Backend instead of executing them locally via IAM. Key changes include adding the executeSchemaMigration client function, updating handleIncompatibleSchemaError to support this delegation, and adding corresponding unit tests. Feedback on the changes highlights a logic bug where superuser commands are incorrectly sent to the backend alongside owner commands, a style guide violation regarding the use of any types in the new client function, and a corresponding need to update the client unit tests to match the corrected types.

[joehan]

/joe-review

[joehan]

⚠️ Disclaimer: This draft review was generated by an AI review agent. Please verify all findings before acting on them.

Code Review Summary: API-based Schema Migration (firebase/firebase-tools)
This PR introduces the fdcapimigration experimental flag to delegate SQL schema migrations to the FDC Backend. It also adds client-side preflight validation for new NOT NULL constraints.

🟢 Strengths & LGTM Aspects
Correctly gates the new schema migration path behind the fdcapimigration experimental flag.
Good test coverage for the new preflight validation logic and the conditional execution flow.
Standard cleanup of sinon stubs in afterEach hooks.
🔴 Overview of Findings & Action Items
AI/Agent Artifacts: A significant number of empty JSDoc comment blocks (/**\n *\n */) were added to functions in client.ts and schemaMigration.ts. These should be removed.
TypeScript Safety:
options in performClientSidePreflightValidation is typed as any and is unused.
Redundant as any cast on riskTags check in schemaMigration.ts.
Extensive use of any / as any in schemaMigration.spec.ts for mocking Schema, IncompatibleSqlSchemaError, and Options. Use proper type assertions or partial types instead.
API Design: performClientSidePreflightValidation has unused parameters (options, instanceId, databaseId) that should be removed.
🟡 Nits & Suggestions
The regex in performClientSidePreflightValidation assumes table names are always quoted. Consider making quotes optional for robustness.

[joehan]

🔴 [TypeScript Safety] Avoid any in tests

Rationale: Using any reduces type safety even in tests. Use type assertions to Schema or Partial<Schema> instead.

Suggested Fix:

  const schema = {
    name: "projects/p/locations/l/services/s/schemas/main",
  } as Schema;