fix(migrations): make Rebased rollback safe

test/pleroma/repo/optional_migrations/rebased_rollbacks_test.exs

@@ -0,0 +1,174 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Repo.OptionalMigrations.RebasedRollbacksTest do
+  use ExUnit.Case, async: false
+
+  alias Ecto.Adapters.SQL
+
+  defmodule MigrationRepo do
+    use Ecto.Repo,
+      otp_app: :pleroma,
+      adapter: Ecto.Adapters.Postgres
+  end
+
+  @migrations_path "priv/repo/migrations"
+  @rollbacks_path "priv/repo/optional_migrations/rebased_rollbacks"
+
+  @expected_versions ~w{
+    20210612185407
+    20220314220000
+    20220819171321
+    20220927220033
+    20221207235104
+  }
+
+  test "only includes Rebased-specific migration versions" do
+    rollback_versions = migration_versions(@rollbacks_path)
+    pleroma_versions = migration_versions(@migrations_path)
+
+    assert rollback_versions == @expected_versions
+    assert MapSet.disjoint?(MapSet.new(rollback_versions), MapSet.new(pleroma_versions))
+  end
+
+  test "rolls back Rebased schema without removing Pleroma data" do
+    prefix = "rebased_rollbacks_#{Ecto.UUID.generate() |> String.replace("-", "")}"
+
+    repo_config = [
+      username: "postgres",
+      password: "postgres",
+      database: System.get_env("DB_NAME", "pleroma_test"),
+      hostname: System.get_env("DB_HOST", "localhost"),
+      port: String.to_integer(System.get_env("DB_PORT", "5432")),
+      pool_size: 2,
+      parameters: [search_path: prefix]
+    ]
+
+    {:ok, repo} = MigrationRepo.start_link(repo_config)
+    Process.unlink(repo)
+
+    on_exit(fn ->
+      query!("DROP SCHEMA IF EXISTS #{prefix} CASCADE")
+      MigrationRepo.stop()
+    end)
+
+    query!("CREATE SCHEMA #{prefix}")
+
+    create_rebased_schema()
+
+    expected_rollbacks =
+      @expected_versions
+      |> Enum.reverse()
+      |> Enum.map(&String.to_integer/1)
+
+    assert Ecto.Migrator.run(MigrationRepo, @rollbacks_path, :down, all: true) ==
+             expected_rollbacks
+
+    assert query!("SELECT version FROM schema_migrations ORDER BY version").rows == [
+             [20_220_624_104_914],
+             [20_221_029_171_353]
+           ]
+
+    assert query!("""
+           SELECT column_name
+           FROM information_schema.columns
+           WHERE table_schema = current_schema() AND table_name = 'users'
+           ORDER BY column_name
+           """).rows == [["id"]]
+
+    assert query!("SELECT type::text FROM notifications ORDER BY type::text").rows == [["status"]]
+
+    assert query!("""
+           SELECT enumlabel
+           FROM pg_enum
+           JOIN pg_type ON pg_type.oid = enumtypid
+           JOIN pg_namespace ON pg_namespace.oid = pg_type.typnamespace
+           WHERE typname = 'notification_type' AND nspname = current_schema()
+           ORDER BY enumsortorder
+           """).rows ==
+             Enum.map(
+               ~w{follow follow_request mention move pleroma:emoji_reaction pleroma:chat_mention reblog favourite pleroma:report poll status update},
+               &[&1]
+             )
+
+    assert query!("SELECT to_regclass('objects_events')").rows == [[nil]]
+
+    assert query!("SELECT url, secret, internal FROM webhooks").rows == [
+             ["https://example.com/webhook", "preserve-me", false]
+           ]
+  end
+
+  defp migration_versions(path) do
+    path
+    |> Path.join("*.exs")
+    |> Path.wildcard()
+    |> Enum.map(fn migration ->
+      migration
+      |> Path.basename()
+      |> String.split("_", parts: 2)
+      |> hd()
+    end)
+    |> Enum.sort()
+  end
+
+  defp create_rebased_schema do
+    statements = [
+      """
+      CREATE TYPE notification_type AS ENUM (
+        'follow', 'follow_request', 'mention', 'move', 'pleroma:emoji_reaction',
+        'pleroma:chat_mention', 'reblog', 'favourite', 'pleroma:report', 'poll',
+        'status', 'update', 'pleroma:participation_accepted',
+        'pleroma:participation_request', 'pleroma:event_reminder',
+        'pleroma:event_update'
+      )
+      """,
+      "CREATE TABLE notifications (id bigserial PRIMARY KEY, type notification_type)",
+      """
+      INSERT INTO notifications (type) VALUES
+        ('status'),
+        ('pleroma:participation_accepted'),
+        ('pleroma:participation_request'),
+        ('pleroma:event_reminder'),
+        ('pleroma:event_update')
+      """,
+      """
+      CREATE TABLE users (
+        id bigserial PRIMARY KEY,
+        accepts_email_list boolean,
+        location varchar(255),
+        last_move_at timestamp
+      )
+      """,
+      "CREATE TABLE objects (id bigserial PRIMARY KEY, data jsonb)",
+      "CREATE INDEX objects_events ON objects ((data->>'type')) WHERE data->>'type' = 'Event'",
+      """
+      CREATE TABLE webhooks (
+        id bigserial PRIMARY KEY,
+        url varchar(255) NOT NULL,
+        events varchar[] NOT NULL DEFAULT '{}',
+        secret varchar(255) NOT NULL DEFAULT '',
+        enabled boolean NOT NULL DEFAULT true,
+        internal boolean NOT NULL DEFAULT false
+      )
+      """,
+      "CREATE UNIQUE INDEX webhooks_url_index ON webhooks (url)",
+      "INSERT INTO webhooks (url, secret) VALUES ('https://example.com/webhook', 'preserve-me')",
+      "CREATE TABLE schema_migrations (version bigint PRIMARY KEY, inserted_at timestamp(0))",
+      """
+      INSERT INTO schema_migrations (version, inserted_at) VALUES
+        (20210612185407, NOW()),
+        (20220314220000, NOW()),
+        (20220624104914, NOW()),
+        (20220819171321, NOW()),
+        (20220927220033, NOW()),
+        (20221029171353, NOW()),
+        (20221207235104, NOW())
+      """
+    ]
+
+    Enum.each(statements, &query!/1)
+  end
+
+  defp query!(statement), do: SQL.query!(MigrationRepo, statement, [])
+end