flyway-or-liquibase-detection

name	flyway-or-liquibase-detection
description	Auto-detect the project's DB migration tool and follow its conventions. Never use both. Use when designing or writing a schema change.

Flyway or Liquibase detection

Detection

.github/scripts/detect-stack.sh reports one of:

• flyway — flyway-core in pom.xml AND src/main/resources/db/migration/ exists.
• liquibase — liquibase-core in pom.xml AND src/main/resources/db/changelog/ exists.
• none — neither.
• both — fatal. Refuse to proceed; ask the user to remove one.

Record the result in 03-design.md under ### Inputs from detect-stack.sh.

Flyway conventions

• File path: src/main/resources/db/migration/V{version}__{description}.sql
• Versioning: V1__init.sql, V2__add_gift_card_table.sql, V3__add_index_gift_card_code.sql
• One migration per logical change. Never edit a checked-in migration; add a new one.
• Repeatable migrations (views, functions): R__view_active_orders.sql.
• Forward-only by default. If a migration is destructive, the design must include a ## Rollback section in 03-design.md.

-- V12__add_gift_card_table.sql
CREATE TABLE gift_card (
    id          UUID PRIMARY KEY,
    code        VARCHAR(64) NOT NULL UNIQUE,
    balance     NUMERIC(12,2) NOT NULL CHECK (balance >= 0),
    created_at  TIMESTAMPTZ NOT NULL DEFAULT now()
);
CREATE INDEX ix_gift_card_code ON gift_card(code);

Liquibase conventions

• Master changelog: src/main/resources/db/changelog/db.changelog-master.yaml
• Per-feature changeset file: db/changelog/changes/2026-04-18-gift-card.yaml
• Include via <include file="changes/2026-04-18-gift-card.yaml"/>.
• Each changeset has id, author, and is immutable once merged.

databaseChangeLog:
  - changeSet:
      id: gift-card-1
      author: spring-implementer
      changes:
        - createTable:
            tableName: gift_card
            columns:
              - column: { name: id, type: UUID, constraints: { primaryKey: true } }
              - column: { name: code, type: VARCHAR(64), constraints: { nullable: false, unique: true } }
              - column: { name: balance, type: NUMERIC(12,2), constraints: { nullable: false } }
              - column: { name: created_at, type: TIMESTAMPTZ, defaultValueComputed: now() }

Tests

• Migrations run automatically inside the Testcontainers Postgres container at test boot.
• A dedicated MigrationsIT runs flyway:info (or liquibase status) at the latest version and asserts no pending migrations.

Anti-patterns

• Editing a previously released migration → checksum mismatch → production breaks.
• Using Flyway.repair() in code paths.
• DROP TABLE without an ADR.
• Renaming a column with no two-step migration (add new → backfill → switch reads → switch writes → drop old).
• Two migration tools coexisting (both is fatal).