ef-migration

name	ef-migration
description	Add or apply an EF Core migration for the BlackIce.Server.Data layer (BlackIceDbContext), with the correct --project/--startup-project wiring and the SQLite-vs-MySQL provider caveat handled. Invoke with /ef-migration <MigrationName>.
disable-model-invocation	true

EF Core migration helper (BlackIce.Server.Data)

The data layer (server/BlackIce.Server.Data, BlackIceDbContext) currently provisions its schema with EnsureCreated — migrations are deferred. Use this skill when adopting migrations or adding one. The DbContext lives in BlackIce.Server.Data; the runnable entry point (which supplies configuration/DI) is BlackIce.Server.Host, so EF must be told both.

0. Prerequisites (check first)

dotnet ef --version            # if "command not found":
dotnet tool install --global dotnet-ef

1. ⚠️ Provider caveat — decide before generating

The project supports two providers (SQLite default + Pomelo MySQL, swapped via blackice.server.json). EF migrations are provider-specific — a migration scaffolded against SQLite will not faithfully apply to MySQL and vice-versa. Pick the approach:

• Single-provider (simplest, recommended for now): generate against the default SQLite provider only. Document that MySQL deployments use EnsureCreated or a manual schema until multi-provider migrations are set up.
• Multi-provider (only if you ship MySQL): maintain separate migration sets, e.g. Migrations/Sqlite and Migrations/MySql, selected by a design-time factory that reads which provider is active. This is a larger change — confirm with the user before doing it.

The design-time provider is whatever BlackIceDbContext / the Host resolves by default (SQLite, Data Source=blackice.db). Ensure config selects the intended provider before running.

2. First migration (transition off EnsureCreated)

If no migrations exist yet, the initial migration must match the schema EnsureCreated already produces, and the dev DB must be recreated:

dotnet ef migrations add InitialCreate \
  --project server/BlackIce.Server.Data \
  --startup-project server/BlackIce.Server.Host \
  --context BlackIceDbContext

Then switch the Host's startup from EnsureCreated() to Migrate() (or context.Database.Migrate()), and delete any stale dev *.db so it's rebuilt from migrations.

3. Add a migration (ongoing)

dotnet ef migrations add <MigrationName> \
  --project server/BlackIce.Server.Data \
  --startup-project server/BlackIce.Server.Host \
  --context BlackIceDbContext

Inspect the generated Up/Down in server/BlackIce.Server.Data/Migrations/ — confirm it matches intent and that Down cleanly reverses Up.

4. Validate before committing

# Applies migrations to a throwaway DB to prove they run end-to-end:
dotnet ef database update \
  --project server/BlackIce.Server.Data \
  --startup-project server/BlackIce.Server.Host \
  --context BlackIceDbContext
dotnet build server/BlackIce.Server.sln
dotnet test  server/BlackIce.Server.sln

Commit the migration files with a feat(data): message. Do not commit the resulting *.db (gitignored, and the leak-guard blocks it).