Support Flyway's defaultSchema configuration option

Originally reported at: https://stackoverflow.com/q/70744765/2504224

extensions/flyway/deployment/src/test/resources/clean-at-start-config.properties

@@ -1,12 +1,14 @@
 quarkus.datasource.db-kind=h2
 quarkus.datasource.username=sa
 quarkus.datasource.password=sa
-quarkus.datasource.jdbc.url=jdbc:h2:tcp://localhost/mem:test-quarkus-clean-at-start;DB_CLOSE_DELAY=-1;
+quarkus.datasource.jdbc.url=jdbc:h2:tcp://localhost/mem:test-quarkus-clean-at-start;DB_CLOSE_DELAY=-1;INIT=CREATE SCHEMA IF NOT EXISTS TEST
 
 # Flyway config properties
 quarkus.flyway.clean-at-start=true
 quarkus.flyway.migrate-at-start=false
 quarkus.flyway.table=test_flyway_history
+quarkus.flyway.default-schema=PUBLIC
+quarkus.flyway.schemas=TEST,PUBLIC
 quarkus.flyway.baseline-on-migrate=false
 quarkus.flyway.baseline-version=0.0.1
 quarkus.flyway.baseline-description=Initial description for test

extensions/flyway/runtime/src/main/java/io/quarkus/flyway/runtime/FlywayCreator.java

@@ -38,6 +38,9 @@ public Flyway createFlyway(DataSource dataSource) {
         if (flywayRuntimeConfig.connectRetries.isPresent()) {
             configure.connectRetries(flywayRuntimeConfig.connectRetries.getAsInt());
         }
+        if (flywayRuntimeConfig.defaultSchema.isPresent()) {
+            configure.defaultSchema(flywayRuntimeConfig.defaultSchema.get());
+        }
         if (flywayRuntimeConfig.schemas.isPresent()) {
             configure.schemas(flywayRuntimeConfig.schemas.get().toArray(EMPTY_ARRAY));
         }

extensions/flyway/runtime/src/main/java/io/quarkus/flyway/runtime/FlywayDataSourceRuntimeConfig.java

@@ -28,6 +28,21 @@ public static final FlywayDataSourceRuntimeConfig defaultConfig() {
     @ConfigItem
     public OptionalInt connectRetries = OptionalInt.empty();
 
+    /**
+     * Sets the default schema managed by Flyway. This schema name is case-sensitive. If not specified, but <i>schemas</i>
+     * is, Flyway uses the first schema in that list. If that is also not specified, Flyway uses the default schema for the
+     * database connection.
+     * <p>
+     * Consequences:
+     * </p>
+     * <ul>
+     * <li>This schema will be the one containing the schema history table.</li>
+     * <li>This schema will be the default for the database connection (provided the database supports this concept).</li>
+     * </ul>
+     */
+    @ConfigItem
+    public Optional<String> defaultSchema = Optional.empty();
+
     /**
      * Comma-separated case-sensitive list of schemas managed by Flyway.
      * The first schema in the list will be automatically set as the default one during the migration.