fix(catalog): encode default table locations with UTF-8

buildPrefixedLocation derived a table's default storage location by
percent-encoding the namespace levels and table name with
URLEncoder.encode(..., Charset.defaultCharset()). For non-ASCII
identifiers the persisted location then depended on the JVM's default
charset, so the same table could resolve to a different (or lossy)
location on a non-UTF-8 JVM, breaking portability and round-trip
expectations.

Encode both segments with StandardCharsets.UTF_8, matching
PolarisEntityUtils.encodeNamespace and every other URLEncoder call site
in the service. Add a regression test that creates a table under
non-ASCII namespace and table identifiers with object-storage prefixing
enabled and asserts the derived location uses the UTF-8 percent-encoded
form regardless of the platform default charset.

Author: anxkhn

CHANGELOG.md

@@ -79,6 +79,7 @@ request adding CHANGELOG notes for breaking (!) changes and possibly other secti
 - Inheritable policy mapping inserts in the JDBC backend now use the active transaction connection, so they roll back correctly with the surrounding transaction.
 - Generic table drop now accepts table-scoped `TABLE_DROP` privilege.
 - Azure SAS tokens are now signed for the configured duration instead of a hardcoded 1 hour, so long jobs no longer fail with expired credentials.
+- Default table storage locations with object-storage prefixing enabled are now percent-encoded with UTF-8 instead of the JVM default charset. Previously the persisted location of a table under a non-ASCII namespace or table name depended on the platform default charset, so the same table could resolve to a different (or lossy) location on a non-UTF-8 JVM.
 
 ## [1.5.0]
 

runtime/service/src/main/java/org/apache/polaris/service/catalog/iceberg/LocalIcebergCatalog.java

@@ -34,7 +34,7 @@
 import java.io.Closeable;
 import java.io.IOException;
 import java.net.URLEncoder;
-import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -1128,11 +1128,11 @@ private String buildPrefixedLocation(TableIdentifier tableIdentifier) {
     locationBuilder.append(LocationUtils.computeHash(tableIdentifier.toString()));
 
     for (String ns : tableIdentifier.namespace().levels()) {
-      locationBuilder.append("/").append(URLEncoder.encode(ns, Charset.defaultCharset()));
+      locationBuilder.append("/").append(URLEncoder.encode(ns, StandardCharsets.UTF_8));
     }
     locationBuilder
         .append("/")
-        .append(URLEncoder.encode(tableIdentifier.name(), Charset.defaultCharset()))
+        .append(URLEncoder.encode(tableIdentifier.name(), StandardCharsets.UTF_8))
         .append("/");
     return locationBuilder.toString();
   }

runtime/service/src/test/java/org/apache/polaris/service/catalog/iceberg/IcebergOverlappingTableTest.java

@@ -27,6 +27,8 @@
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 import jakarta.ws.rs.core.Response;
+import java.net.URLEncoder;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Path;
 import java.util.List;
 import java.util.Map;
@@ -144,14 +146,18 @@ private int createTableStaged(TestServices services, String location) {
    * creation fails, this should return null
    */
   private String createTableWithName(TestServices services, String name) {
+    return createTableWithName(services, namespace, name);
+  }
+
+  private String createTableWithName(TestServices services, String namespaceName, String name) {
     CreateTableRequest createTableRequest =
         CreateTableRequest.builder().withName(name).withSchema(SCHEMA).build();
     try (Response response =
         services
             .restApi()
             .createTable(
                 catalog,
-                namespace,
+                namespaceName,
                 createTableRequest,
                 null,
                 IDEMPOTENCY_KEY,
@@ -169,6 +175,14 @@ private String createTableWithName(TestServices services, String name) {
 
   private void createCatalogAndNamespace(
       TestServices services, Map<String, String> catalogConfig, String catalogLocation) {
+    createCatalogAndNamespace(services, catalogConfig, catalogLocation, namespace);
+  }
+
+  private void createCatalogAndNamespace(
+      TestServices services,
+      Map<String, String> catalogConfig,
+      String catalogLocation,
+      String namespaceName) {
     CatalogProperties.Builder propertiesBuilder =
         CatalogProperties.builder()
             .setDefaultBaseLocation(String.format("%s/%s", catalogLocation, catalog))
@@ -198,7 +212,7 @@ private void createCatalogAndNamespace(
     }
 
     CreateNamespaceRequest createNamespaceRequest =
-        CreateNamespaceRequest.builder().withNamespace(Namespace.of(namespace)).build();
+        CreateNamespaceRequest.builder().withNamespace(Namespace.of(namespaceName)).build();
     try (Response response =
         services
             .restApi()
@@ -727,4 +741,55 @@ void testParentChildOverlapWithOptimizedSiblingCheck(@TempDir Path tempDir) {
     assertThat(createTable(services, derivedLocation + "/child"))
         .isEqualTo(Response.Status.FORBIDDEN.getStatusCode());
   }
+
+  @Test
+  @DisplayName("Hashed default location encodes non-ASCII identifiers with UTF-8")
+  void testHashedTableLocationsEncodeNonAsciiIdentifiersAsUtf8(@TempDir Path tempDir) {
+    // Uses non-ASCII namespace and table identifiers to pin the durable location encoding to
+    // UTF-8. With the platform default charset the persisted percent-encoding would vary (or be
+    // lossy) across JVMs, so the derived location must always be the UTF-8 encoded form.
+    Map<String, Object> strictServicesWithOptimizedOverlapCheck =
+        Map.of(
+            "ALLOW_UNSTRUCTURED_TABLE_LOCATION",
+            "false",
+            "ALLOW_TABLE_LOCATION_OVERLAP",
+            "false",
+            "ALLOW_INSECURE_STORAGE_TYPES",
+            "true",
+            "SUPPORTED_CATALOG_STORAGE_TYPES",
+            List.of("FILE", "S3"),
+            OPTIMIZED_SIBLING_CHECK.key(),
+            "true");
+    Map<String, String> hashedCatalog =
+        Map.of(
+            DEFAULT_LOCATION_OBJECT_STORAGE_PREFIX_ENABLED.catalogConfig(),
+            "true",
+            ALLOW_UNSTRUCTURED_TABLE_LOCATION.catalogConfig(),
+            "true");
+
+    TestServices services =
+        TestServices.builder().config(strictServicesWithOptimizedOverlapCheck).build();
+
+    String baseLocation = tempDir.toAbsolutePath().toUri().toString();
+    if (baseLocation.endsWith("/")) {
+      baseLocation = baseLocation.substring(0, baseLocation.length() - 1);
+    }
+
+    String nonAsciiNamespace = "n\u00e9\u6f22"; // né漢
+    createCatalogAndNamespace(services, hashedCatalog, baseLocation, nonAsciiNamespace);
+
+    String nonAsciiTableName = "t\u00e9\u6f22"; // té漢
+    String tableLocation = createTableWithName(services, nonAsciiNamespace, nonAsciiTableName);
+    Assertions.assertNotNull(tableLocation);
+
+    String expectedEncodedSuffix =
+        String.format(
+            "/%s/%s",
+            URLEncoder.encode(nonAsciiNamespace, StandardCharsets.UTF_8),
+            URLEncoder.encode(nonAsciiTableName, StandardCharsets.UTF_8));
+    assertThat(tableLocation).endsWith(expectedEncodedSuffix);
+    // The raw (unencoded) identifiers must never appear verbatim in the durable location.
+    assertThat(tableLocation).doesNotContain(nonAsciiNamespace);
+    assertThat(tableLocation).doesNotContain(nonAsciiTableName);
+  }
 }