Do not require a default datasource definition when using a MultiTenantConnectionProvider

extensions/hibernate-orm/runtime/src/main/java/io/quarkus/hibernate/orm/runtime/FastBootHibernatePersistenceProvider.java

@@ -36,6 +36,7 @@
 import io.quarkus.hibernate.orm.runtime.config.DatabaseOrmCompatibilityVersion;
 import io.quarkus.hibernate.orm.runtime.integration.HibernateOrmIntegrationRuntimeDescriptor;
 import io.quarkus.hibernate.orm.runtime.integration.HibernateOrmIntegrationRuntimeInitListener;
+import io.quarkus.hibernate.orm.runtime.migration.MultiTenancyStrategy;
 import io.quarkus.hibernate.orm.runtime.recording.PrevalidatedQuarkusMetadata;
 import io.quarkus.hibernate.orm.runtime.recording.RecordedState;
 
@@ -222,7 +223,8 @@ private RuntimeSettings buildRuntimeSettings(String persistenceUnitName, Recorde
         Optional<String> dataSourceName = recordedState.getBuildTimeSettings().getSource().getDataSource();
         if (dataSourceName.isPresent()) {
             // Inject the datasource
-            injectDataSource(persistenceUnitName, dataSourceName.get(), runtimeSettingsBuilder);
+            injectDataSource(persistenceUnitName, dataSourceName.get(), recordedState.getMultiTenancyStrategy(),
+                    runtimeSettingsBuilder);
         }
 
         // Inject runtime configuration if the persistence unit was defined by Quarkus configuration
@@ -397,8 +399,10 @@ private void verifyProperties(Map properties) {
     }
 
     private static void injectDataSource(String persistenceUnitName, String dataSourceName,
+            MultiTenancyStrategy multiTenancyStrategy,
             RuntimeSettings.Builder runtimeSettingsBuilder) {
-        // first convert
+        // Note: the counterpart of this code, but for multitenancy (injecting the connection provider),
+        // can be found in io.quarkus.hibernate.orm.runtime.boot.FastBootMetadataBuilder.mergeSettings
 
         if (runtimeSettingsBuilder.isConfigured(AvailableSettings.URL) ||
                 runtimeSettingsBuilder.isConfigured(AvailableSettings.DATASOURCE) ||
@@ -410,6 +414,16 @@ private static void injectDataSource(String persistenceUnitName, String dataSour
             return;
         }
 
+        if (multiTenancyStrategy != null && multiTenancyStrategy != MultiTenancyStrategy.NONE
+                && multiTenancyStrategy != MultiTenancyStrategy.DISCRIMINATOR) {
+            // Nothing to do: the datasource retrieval will be handled dynamically
+            // by an implementation of TenantConnectionResolver -- for instance
+            // io.quarkus.hibernate.orm.runtime.tenant.DataSourceTenantConnectionResolver.
+            // In the case of database multi-tenancy, that connection resolver
+            // might not even use the assigned datasource.
+            return;
+        }
+
         DataSource dataSource;
         try {
             // ClientProxy.unwrap is necessary to trigger exceptions on inactive datasources

extensions/hibernate-orm/runtime/src/main/java/io/quarkus/hibernate/orm/runtime/boot/FastBootMetadataBuilder.java

@@ -248,6 +248,9 @@ private MergedSettings mergeSettings(QuarkusPersistenceUnitDefinition puDefiniti
 
         if (multiTenancyStrategy != null && multiTenancyStrategy != MultiTenancyStrategy.NONE
                 && multiTenancyStrategy != MultiTenancyStrategy.DISCRIMINATOR) {
+            // Note: the counterpart of this code, but for single-tenancy (injecting the datasource),
+            // can be found in io.quarkus.hibernate.orm.runtime.FastBootHibernatePersistenceProvider.injectDataSource
+
             // We need to initialize the multi tenant connection provider
             // on static init as it is used in MetadataBuildingOptionsImpl
             // to determine if multi-tenancy is enabled.

integration-tests/hibernate-orm-tenancy/connection-resolver-legacy-qualifiers/src/main/resources/application.properties

@@ -6,8 +6,10 @@ quarkus.hibernate-orm.multitenant=database
 quarkus.hibernate-orm.dialect=MariaDB
 quarkus.hibernate-orm.packages=io.quarkus.it.hibernate.multitenancy.fruit
 
-# We create datasources manually, so a lack of configuration doesn't mean Quarkus should step in with defaults.
-quarkus.datasource.devservices.enabled=false
+# We create datasources programmatically, so we don't need the default datasource.
+# This makes sure Quarkus won't create a default datasource in test/dev mode.
+# This also helps reproduce https://github.com/quarkusio/quarkus/issues/29269.
+quarkus.datasource.active=false
 
 # Inventory persistence unit
 quarkus.hibernate-orm."inventory".schema-management.strategy=none

integration-tests/hibernate-orm-tenancy/connection-resolver/src/main/resources/application.properties

@@ -6,8 +6,10 @@ quarkus.hibernate-orm.multitenant=database
 quarkus.hibernate-orm.dialect=MariaDB
 quarkus.hibernate-orm.packages=io.quarkus.it.hibernate.multitenancy.fruit
 
-# We create datasources manually, so a lack of configuration doesn't mean Quarkus should step in with defaults.
-quarkus.datasource.devservices.enabled=false
+# We create datasources programmatically, so we don't need the default datasource.
+# This makes sure Quarkus won't create a default datasource in test/dev mode.
+# This also helps reproduce https://github.com/quarkusio/quarkus/issues/29269.
+quarkus.datasource.active=false
 
 # Inventory persistence unit
 quarkus.hibernate-orm."inventory".schema-management.strategy=none