refactor: Use a stable sequence for the computed "RegistrationProgramId"s

[RubenGeo]

AB#44393

Describe your changes

Okay in the end I went the more robust but more code route. This guarantees parallel processes can never be assigned the same registrationProgramId.

Checklist before requesting a code review

• I have performed a self-review of my code
• I have addressed all Copilot comments
• I have asked the design team to review these changes, or: The changes do not touch the UI/UX
• I have added tests for my changes, or: Adding tests is unnecessary/irrelevant
• I have made sure that all automated checks pass before requesting a review
• I have updated all documentation where necessary
• I have checked the list of integrations with the 121 API for changed endpoints
• I do not need any deviation from our PR guidelines

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[Copilot]

🟡 Changes recommended

Unresolved critical test-isolation and moderate concurrency/backfill issues block approval.

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Pull request overview

Adds a persistent per-program counter to assign unique sequential registrationProgramId values safely under concurrency.

Changes:

• Adds the counter entity, repository, relation, and module wiring.
• Uses atomic counter allocation for registrations.
• Adds migration backfill, seed updates, and integration coverage.

File summaries

File	Summary	Review findings
services/121-service/test/registrations/assign-registration-program-id.test.ts	Adds counter-based assignment tests.	Critical (3 votes): Restore beforeEach database resets to isolate scenarios.
services/121-service/src/scripts/services/seed-helper.service.ts	Initializes counters for seeded programs.	—
services/121-service/src/scripts/factories/registration-seed-factory.ts	Synchronizes counters after bulk duplication.	Moderate (2 votes): Reserve ID ranges atomically to prevent collisions with API imports.
services/121-service/src/registration/repositories/registration-scoped.repository.ts	Allocates registration IDs atomically.	Nit (1 vote): Add an alias when creating the query builder.
services/121-service/src/registration/registrations.module.ts	Registers the counter entity.	—
services/121-service/src/programs/repositories/program-registration-program-id-counter.repository.ts	Provides counter creation.	—
services/121-service/src/programs/programs.service.ts	Creates counters with programs.	—
services/121-service/src/programs/programs.module.ts	Registers and exports counter dependencies.	—
services/121-service/src/programs/entities/program.entity.ts	Adds the counter relation.	—
services/121-service/src/programs/entities/program-registration-program-id-counter.entity.ts	Defines counter persistence.	Nit (1 vote): Remove the redundant unique index.
services/121-service/src/migration/1788794699491-add-program-registration-program-id-counter.ts	Creates and backfills the counter table.	Moderate (1 vote): Add coverage for existing programs and the empty-program backfill case.

Review details

Suppressed comments (3)

services/121-service/src/migration/1788794699491-add-program-registration-program-id-counter.ts:25

• The migration backfill is not exercised by the added integration test: that test creates a program after migrations, while API resets only truncate tables and do not rerun migrations (services/121-service/src/scripts/seed-init.ts:341-372). Add incremental-migration coverage with an existing program whose registrations have a known maximum, and assert the next imported ID is MAX + 1 (plus the empty-program case), otherwise an incorrect backfill can pass CI and break existing programs after upgrade.

      `INSERT INTO "121-service"."program_registration_program_id_counter" ("programId", "lastRegistrationProgramId")
       SELECT p.id, COALESCE(MAX(r."registrationProgramId"), 0)
       FROM "121-service"."program" p
       LEFT JOIN "121-service"."registration" r ON r."programId" = p.id
       GROUP BY p.id
       ON CONFLICT ("programId") DO NOTHING`,

services/121-service/src/programs/entities/program-registration-program-id-counter.entity.ts:18

• The one-to-one @JoinColumn already makes the owning programId unique; with this decorator the migration creates both the REL_... UNIQUE constraint and a second IDX_... unique index on the same column (lines 8 and 14 of the migration). Remove the redundant index definition and its generated migration statement to avoid duplicate index storage and write overhead.

  @Index({ unique: true })

services/121-service/src/registration/repositories/registration-scoped.repository.ts:90

• This query builder is created without an alias, which violates the service repository guideline and differs from the aliased update builders elsewhere (for example, services/121-service/src/payments/transactions/transaction.repository.ts). Create it with an alias so the update remains unambiguous if it is extended.

    const updateResult = await this.counterRepository
      .createQueryBuilder()
      .update(ProgramRegistrationProgramIdCounterEntity)

• Files reviewed: 11/11 changed files
• Comments generated: 2
• Review effort level: Lite

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[elwinschmitz]

"Naming things is hard". ;)