Default PURGE_VIEW_METADATA_ON_DROP to false so views can be dropped out of the box

CHANGELOG.md

@@ -42,6 +42,12 @@ request adding CHANGELOG notes for breaking (!) changes and possibly other secti
 
 ### Changes
 
+- `PURGE_VIEW_METADATA_ON_DROP` now defaults to `false`, so views can be dropped under the default
+  configuration. Its previous default of `true` required `DROP_WITH_PURGE_ENABLED` to be enabled as
+  well, and dropping any view failed otherwise. Deployments that enable `DROP_WITH_PURGE_ENABLED`
+  and rely on view metadata being purged should now set `PURGE_VIEW_METADATA_ON_DROP` to `true`
+  explicitly.
+
 ### Deprecations
 
 ### Fixes

integration-tests/src/main/java/org/apache/polaris/service/it/test/PolarisRestCatalogIntegrationBase.java

@@ -1912,6 +1912,27 @@ public void testDropViewWithPurge() {
     assertThatCode(() -> restCatalog.dropView(id)).doesNotThrowAnyException();
   }
 
+  @Test
+  public void testDropViewWithDefaultPurgeViewMetadataOnDrop() {
+    restCatalog.createNamespace(Namespace.of("ns1"));
+    TableIdentifier id = TableIdentifier.of(Namespace.of("ns1"), "view1");
+    restCatalog
+        .buildView(id)
+        .withSchema(SCHEMA)
+        .withDefaultNamespace(Namespace.of("ns1"))
+        .withQuery("spark", VIEW_QUERY)
+        .create();
+
+    Catalog catalog = managementApi.getCatalog(currentCatalogName);
+    Map<String, String> catalogProps = new HashMap<>(catalog.getProperties().toMap());
+    catalogProps.put(FeatureConfiguration.DROP_WITH_PURGE_ENABLED.catalogConfig(), "false");
+    // Leave PURGE_VIEW_METADATA_ON_DROP unset so that its default value applies.
+    catalogProps.remove(FeatureConfiguration.PURGE_VIEW_METADATA_ON_DROP.catalogConfig());
+    managementApi.updateCatalog(catalog, catalogProps);
+
+    assertThatCode(() -> restCatalog.dropView(id)).doesNotThrowAnyException();
+  }
+
   @Test
   public void testRenameViewStatus() {
     String tableName = "tbl1";

polaris-core/src/main/java/org/apache/polaris/core/config/FeatureConfiguration.java

@@ -436,8 +436,9 @@ public static void enforceFeatureEnabledOrThrow(
           .key("PURGE_VIEW_METADATA_ON_DROP")
           .catalogConfig("polaris.config.purge-view-metadata-on-drop")
           .description(
-              "If set to true, Polaris will attempt to delete view metadata files when a view is dropped.")
-          .defaultValue(true)
+              "If set to true, Polaris will attempt to delete view metadata files when a view is dropped."
+                  + " This requires DROP_WITH_PURGE_ENABLED to be enabled as well.")
+          .defaultValue(false)
           .buildFeatureConfiguration();
 
   public static final FeatureConfiguration<Long> POLARIS_TASK_TIMEOUT_MILLIS =

site/content/in-dev/unreleased/configuration/config-sections/flags-polaris_features.md

@@ -478,10 +478,10 @@ Polaris task expiry timeout (milliseconds). Older unfinished tasks may not be pr
 
 ##### `polaris.features."PURGE_VIEW_METADATA_ON_DROP"`
 
-If set to true, Polaris will attempt to delete view metadata files when a view is dropped.
+If set to true, Polaris will attempt to delete view metadata files when a view is dropped. This requires DROP_WITH_PURGE_ENABLED to be enabled as well.
 
 - **Type:** `Boolean`
-- **Default:** `true`
+- **Default:** `false`
 - **Catalog Config:** `polaris.config.purge-view-metadata-on-drop`
 
 ---