Use a better filter for IMDS.getEntry

Updated InMemoryDirectoryServer.getEntry to use a filter of "(&)"
instead of "(objectClass=*)" when searching for the specified entry.
This should be logically equivalent in the vast majority of cases,
but there may be a difference in a corner case in which the server
is configured without schema and you add an entry without the
objectClass attribute.

src/com/unboundid/ldap/listener/InMemoryDirectoryServer.java

@@ -1579,8 +1579,7 @@ public Schema getSchema(@Nullable final String entryDN)
   public SearchResultEntry getEntry(@NotNull final String dn)
          throws LDAPException
   {
-    return searchForEntry(dn, SearchScope.BASE,
-         Filter.createPresenceFilter("objectClass"));
+    return searchForEntry(dn, SearchScope.BASE, Filter.createANDFilter());
   }
 
 
@@ -1598,8 +1597,8 @@ public SearchResultEntry getEntry(@NotNull final String dn,
                                     @Nullable final String... attributes)
          throws LDAPException
   {
-    return searchForEntry(dn, SearchScope.BASE,
-         Filter.createPresenceFilter("objectClass"), attributes);
+    return searchForEntry(dn, SearchScope.BASE, Filter.createANDFilter(),
+         attributes);
   }
 
 

tests/unit/src/com/unboundid/ldap/listener/InMemoryDirectoryServerAddEmptyEntryTestCase.java

@@ -0,0 +1,84 @@
+/*
+ * Copyright 2023 Ping Identity Corporation
+ * All Rights Reserved.
+ */
+/*
+ * Copyright 2023 Ping Identity Corporation
+ *
+ * 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.
+ */
+/*
+ * Copyright (C) 2023 Ping Identity Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (GPLv2 only)
+ * or the terms of the GNU Lesser General Public License (LGPLv2.1 only)
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses>.
+ */
+package com.unboundid.ldap.listener;
+
+
+
+import org.testng.annotations.Test;
+
+import com.unboundid.ldap.sdk.Entry;
+import com.unboundid.ldap.sdk.LDAPResult;
+import com.unboundid.ldap.sdk.LDAPSDKTestCase;
+import com.unboundid.ldap.sdk.ResultCode;
+import com.unboundid.ldap.sdk.SearchResultEntry;
+
+
+
+/**
+ * This class provides a test that examines the behavior of the in-memory
+ * directory server when an entry with no attributes is added and then
+ * retrieved.
+ */
+public final class InMemoryDirectoryServerAddEmptyEntryTestCase
+     extends LDAPSDKTestCase
+{
+  /**
+   * Tests the behavior when trying to add and retrieve an empty entry.
+   *
+   * @throws  Exception  If an unexpected problem occurs.
+   */
+  @Test()
+  public void testAddAndRetrieveEmptyEntry()
+         throws Exception
+  {
+    // Create an in-memory directory server instance without any schema.
+    final InMemoryDirectoryServerConfig cfg =
+         new InMemoryDirectoryServerConfig("dc=example,dc=com");
+    cfg.setSchema(null);
+
+    final InMemoryDirectoryServer ds = new InMemoryDirectoryServer(cfg);
+
+
+    // Try to add an empty "dc=example,dc=com" entry.
+    final Entry emptyEntry = new Entry("dc=example,dc=com");
+    final LDAPResult addResult = ds.add(emptyEntry);
+    assertResultCodeEquals(addResult, ResultCode.SUCCESS);
+
+    final SearchResultEntry searchEntry = ds.getEntry("dc=example,dc=com");
+    assertNotNull(searchEntry);
+    assertDNsEqual(searchEntry.getDN(), "dc=example,dc=com");
+  }
+}