Add a command to delete feature flags (#2904)

This allows us to delete old ones to avoid confusion, and so that we can
more easily clean up the codebase.

core/src/main/java/google/registry/tools/DeleteFeatureFlagCommand.java

@@ -0,0 +1,84 @@
+// Copyright 2025 The Nomulus Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package google.registry.tools;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static google.registry.persistence.transaction.TransactionManagerFactory.tm;
+
+import com.beust.jcommander.Parameter;
+import com.beust.jcommander.Parameters;
+import google.registry.model.common.FeatureFlag;
+import java.util.List;
+
+/**
+ * Command to remove a {@link FeatureFlag} from the database entirely.
+ *
+ * <p>This should be used when a flag has been deprecated entirely, and we want to remove it, to
+ * avoid having old invalid data in the database.
+ *
+ * <p>This command uses the native query format so that it is able to delete values that are no
+ * longer part of the {@link FeatureFlag} enum.
+ *
+ * <p>This uses {@link ConfirmingCommand} instead of {@link MutatingCommand} because of the
+ * nonstandard deletion flow required by the fact that the enum constant may already have been
+ * removed.
+ */
+@Parameters(separators = " =", commandDescription = "Delete a FeatureFlag from the database")
+public class DeleteFeatureFlagCommand extends ConfirmingCommand {
+
+  @Parameter(description = "Feature flag to delete", required = true)
+  private List<String> mainParameters;
+
+  @Override
+  protected boolean checkExecutionState() {
+    checkArgument(
+        mainParameters != null && !mainParameters.isEmpty() && !mainParameters.getFirst().isBlank(),
+        "Must provide a non-blank feature flag as the main parameter");
+    boolean exists =
+        tm().transact(
+                () ->
+                    (long)
+                            tm().getEntityManager()
+                                .createNativeQuery(
+                                    "SELECT COUNT(*) FROM \"FeatureFlag\" WHERE feature_name ="
+                                        + " :featureName",
+                                    long.class)
+                                .setParameter("featureName", mainParameters.getFirst())
+                                .getSingleResult()
+                        > 0);
+    if (!exists) {
+      System.out.printf("No flag found with name '%s'", mainParameters.getFirst());
+    }
+    return exists;
+  }
+
+  @Override
+  protected String prompt() throws Exception {
+    return String.format("Delete feature flag named '%s'?", mainParameters.getFirst());
+  }
+
+  @Override
+  protected String execute() throws Exception {
+    String featureName = mainParameters.getFirst();
+    tm().transact(
+            () ->
+                tm().getEntityManager()
+                    .createNativeQuery(
+                        "DELETE FROM \"FeatureFlag\" WHERE feature_name = :featureName")
+                    .setParameter("featureName", featureName)
+                    .executeUpdate());
+    return String.format("Deleted feature flag with name '%s'", featureName);
+  }
+}

core/src/main/java/google/registry/tools/RegistryTool.java

@@ -54,6 +54,7 @@ public final class RegistryTool {
           .put("curl", CurlCommand.class)
           .put("delete_allocation_tokens", DeleteAllocationTokensCommand.class)
           .put("delete_domain", DeleteDomainCommand.class)
+          .put("delete_feature_flag", DeleteFeatureFlagCommand.class)
           .put("delete_host", DeleteHostCommand.class)
           .put("delete_premium_list", DeletePremiumListCommand.class)
           .put("delete_reserved_list", DeleteReservedListCommand.class)

core/src/test/java/google/registry/tools/DeleteFeatureFlagCommandTest.java

@@ -0,0 +1,79 @@
+// Copyright 2025 The Nomulus Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package google.registry.tools;
+
+import static com.google.common.truth.Truth.assertThat;
+import static google.registry.model.common.FeatureFlag.FeatureName.TEST_FEATURE;
+import static google.registry.model.common.FeatureFlag.FeatureStatus.ACTIVE;
+import static google.registry.persistence.transaction.TransactionManagerFactory.tm;
+import static google.registry.testing.DatabaseHelper.persistResource;
+import static google.registry.util.DateTimeUtils.START_OF_TIME;
+
+import com.google.common.collect.ImmutableSortedMap;
+import google.registry.model.common.FeatureFlag;
+import org.junit.jupiter.api.Test;
+
+/** Tests for {@link DeleteFeatureFlagCommand}. */
+public class DeleteFeatureFlagCommandTest extends CommandTestCase<DeleteFeatureFlagCommand> {
+
+  @Test
+  void testSimpleSuccess() throws Exception {
+    persistResource(
+        new FeatureFlag()
+            .asBuilder()
+            .setFeatureName(TEST_FEATURE)
+            .setStatusMap(ImmutableSortedMap.of(START_OF_TIME, ACTIVE))
+            .build());
+    assertThat(tm().transact(() -> FeatureFlag.isActiveNow(TEST_FEATURE))).isTrue();
+    runCommandForced("TEST_FEATURE");
+    assertThat(FeatureFlag.getUncached(TEST_FEATURE)).isEmpty();
+  }
+
+  @Test
+  void testSuccess_noLongerPartOfEnum() throws Exception {
+    tm().transact(
+            () ->
+                tm().getEntityManager()
+                    .createNativeQuery(
+                        "INSERT INTO \"FeatureFlag\" VALUES('nonexistent',"
+                            + " '\"1970-01-01T00:00:00.000Z\"=>\"INACTIVE\"')")
+                    .executeUpdate());
+    assertThat(
+            tm().transact(
+                    () ->
+                        tm().query(
+                                "SELECT COUNT(*) FROM FeatureFlag WHERE featureName ="
+                                    + " 'nonexistent'",
+                                long.class)
+                            .getSingleResult()))
+        .isEqualTo(1L);
+    runCommandForced("nonexistent");
+    assertThat(
+            tm().transact(
+                    () ->
+                        tm().query(
+                                "SELECT COUNT(*) FROM FeatureFlag WHERE featureName ="
+                                    + " 'nonexistent'",
+                                long.class)
+                            .getSingleResult()))
+        .isEqualTo(0L);
+  }
+
+  @Test
+  void testFailure_nonExistent() throws Exception {
+    runCommandForced("nonexistent");
+    assertInStdout("No flag found with name 'nonexistent'");
+  }
+}