Core: Fix test failure caused by check empty namespace on REST session catalog

[hantangwangd]

This PR fix the failure test RESTCompatibilityKitCatalogTests.listNamespacesWithEmptyNamespace() running based on RESTSessionCatalog.

In the original implementation, for empty namespaces, RESTSessionCatalog.namespaceExists() would directly throw an NoSuchNamespaceException rather than returning false. This will lead to the failure of the test.

[hantangwangd]

Hi @nastra , can you please take a look at this fix when available? Thanks a lot!

[nastra]

can you please do the same for viewExists and tableExists?

--- a/core/src/main/java/org/apache/iceberg/rest/RESTSessionCatalog.java
+++ b/core/src/main/java/org/apache/iceberg/rest/RESTSessionCatalog.java
@@ -438,9 +438,9 @@ public class RESTSessionCatalog extends BaseViewSessionCatalog
   @Override
   public boolean tableExists(SessionContext context, TableIdentifier identifier) {
     Endpoint.check(endpoints, Endpoint.V1_TABLE_EXISTS);
-    checkIdentifierIsValid(identifier);

     try {
+      checkIdentifierIsValid(identifier);
       client.head(paths.table(identifier), headers(context), ErrorHandlers.tableErrorHandler());
       return true;
     } catch (NoSuchTableException e) {
@@ -659,9 +659,9 @@ public class RESTSessionCatalog extends BaseViewSessionCatalog
   @Override
   public boolean namespaceExists(SessionContext context, Namespace namespace) {
     Endpoint.check(endpoints, Endpoint.V1_NAMESPACE_EXISTS);
-    checkNamespaceIsValid(namespace);

     try {
+      checkNamespaceIsValid(namespace);
       client.head(
           paths.namespace(namespace), headers(context), ErrorHandlers.namespaceErrorHandler());
       return true;
@@ -1233,9 +1233,9 @@ public class RESTSessionCatalog extends BaseViewSessionCatalog
   @Override
   public boolean viewExists(SessionContext context, TableIdentifier identifier) {
     Endpoint.check(endpoints, Endpoint.V1_VIEW_EXISTS);
-    checkViewIdentifierIsValid(identifier);

     try {
+      checkViewIdentifierIsValid(identifier);
       client.head(paths.view(identifier), headers(context), ErrorHandlers.viewErrorHandler());
       return true;
     } catch (NoSuchViewException e) {

[hantangwangd]

Sure!

[nastra]

thanks for fixing this @hantangwangd, LGTM

[hantangwangd]

@nastra My pleasure!

[amogh-jahagirdar]

Late +1 to this PR, noticed the issue last night. Thanks for the fix @hantangwangd!