fix(CopyContent): Moved Multitree validation before copyContentlet call + added DEFAULT variantId logic in PageResourceHelper (#34696)

## Summary

Moved Multitree validation before copyContentlet call + added DEFAULT
variantId logic in PageResourceHelper in case of null/empty values.

## Changes

- Changed the validation order in PageResourceHelper.copyContentlet()
method. Now we validate the existence of the Multitree before actually
copying the Contentlet.
- Added a default value for variantId in case the value from the request
is null or empty.
- Added integration tests.

## Motivation

The issue related to this PR shows that we return a 404 when attempting
to copy a contentlet and the variantId in the request is empty. To
address this, we added logic to set a default value when the variantId
is null or empty.

Additionally, while investigating this issue, we uncovered another
problem. The contentlet was being copied before doing the required
validations for the Multitree. So when the Multitree call returned null,
the response was still a 404, but the contentlet had already been
copied, and the rollback was not being done.

This means the bug was not limited to the empty variantId scenario. Any
case where the Multitree was null could trigger the same unintended
behavior.

## Related Issue
Fixes: [BUG: PUT /api/v1/page/copyContent returns 404 but successfully
copies content when variantId is empty string
#34473](#34473)

Author: ihoffmann-dot

dotCMS/src/main/java/com/dotcms/rest/api/v1/page/PageResourceHelper.java

@@ -492,28 +492,27 @@ protected Contentlet copyContentlet(final CopyContentletForm copyContentletForm,
                                       final PageMode pageMode, final Language language)
             throws DotDataException, DotSecurityException {
 
-        final Tuple2<Contentlet, Contentlet> tuple2 = this.copyContent(copyContentletForm, user, pageMode, language.getId());
-
-        final Contentlet copiedContentlet   = tuple2._1();
-        final Contentlet originalContentlet = tuple2._2();
         final String htmlPage   = copyContentletForm.getPageId();
         final String container  = castToOriginalContainerId(copyContentletForm.getContainerId(), user, pageMode.respectAnonPerms);
         final String contentId  = copyContentletForm.getContentId();
         final String instanceId = copyContentletForm.getRelationType();
-        final String variant    = copyContentletForm.getVariantId();
+        final String variant    = UtilMethods.isSet(copyContentletForm.getVariantId()) ? copyContentletForm.getVariantId() : VariantAPI.DEFAULT_VARIANT.name();
         final int treeOrder     = copyContentletForm.getTreeOrder();
         final String personalization = copyContentletForm.getPersonalization();
         final Map<String, Object> styleProperties = copyContentletForm.getStyleProperties();
 
-        Logger.debug(this, ()-> "Deleting current contentlet multi tree: " + copyContentletForm);
         final MultiTree currentMultitree = getMultiTree(htmlPage, container, contentId, instanceId, personalization, variant);
 
         if (null == currentMultitree) {
-
             throw new DoesNotExistException(
                     "Can not copied the contentlet in the page, because the record is not part of the page, multitree: " + copyContentletForm);
         }
 
+        final Tuple2<Contentlet, Contentlet> tuple2 = this.copyContent(copyContentletForm, user, pageMode, language.getId());
+        final Contentlet copiedContentlet   = tuple2._1();
+        final Contentlet originalContentlet = tuple2._2();
+
+        Logger.debug(this, ()-> "Deleting current contentlet multi tree: " + copyContentletForm);
         APILocator.getMultiTreeAPI().deleteMultiTree(currentMultitree);
 
         final MultiTree newMultitree = new MultiTree(htmlPage, container,

dotcms-integration/src/test/java/com/dotcms/rest/api/v1/page/PageResourceHelperTest.java

@@ -9,6 +9,7 @@
 import com.dotmarketing.beans.Host;
 import com.dotmarketing.beans.MultiTree;
 import com.dotmarketing.business.APILocator;
+import com.dotmarketing.exception.DoesNotExistException;
 import com.dotmarketing.exception.DotDataException;
 import com.dotmarketing.exception.DotSecurityException;
 import com.dotmarketing.portlets.containers.model.Container;
@@ -23,8 +24,6 @@
 import org.junit.BeforeClass;
 import org.junit.Test;
 
-import java.util.Random;
-
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotEquals;
 
@@ -107,6 +106,125 @@ public void copyContentlet() throws DotDataException, DotSecurityException {
         assertNotEquals(contentlet.getInode(), contentletCopy.getInode());
     }
 
+    /**
+     * Method to test: {@link PageResourceHelper#copyContentlet(CopyContentletForm, User, PageMode, Language)}
+     * when: Try to copy a Content from a Page where the Template that is not advanced and the Multi_tree has a
+     * relation_type legacy value and the variantId is empty
+     * should: copy the Contentlet anyway
+     *
+     * @throws DotDataException
+     * @throws DotSecurityException
+     */
+    @Test
+    public void copyContentletWithEmptyVariantId() throws DotDataException, DotSecurityException {
+
+        final RandomString randomString = new RandomString();
+
+        final Field field_1 = new FieldDataGen()
+                .name("field1")
+                .velocityVarName("field1")
+                .type(TextField.class)
+                .next();
+
+        final Field field_2 = new FieldDataGen()
+                .name("field2")
+                .velocityVarName("field2")
+                .type(TextField.class)
+                .next();
+
+        final ContentType contentType = new ContentTypeDataGen()
+                .field(field_1)
+                .field(field_2)
+                .nextPersisted();
+
+        final Contentlet contentlet = new ContentletDataGen(contentType.id())
+                .setProperty("field1", randomString.nextString())
+                .setProperty("field2", randomString.nextString())
+                .nextPersisted();
+
+        final Container container = new ContainerDataGen().nextPersisted();
+        final Host host = new SiteDataGen().nextPersisted();
+        final Template template = new TemplateDataGen()
+                .withContainer(container, ContainerUUID.UUID_LEGACY_VALUE)
+                .nextPersisted();
+
+        final HTMLPageAsset page = new HTMLPageDataGen(host, template).nextPersisted();
+
+        new MultiTreeDataGen().setContentlet(contentlet)
+                .setPage(page)
+                .setContainer(container)
+                .setPersonalization(MultiTree.DOT_PERSONALIZATION_DEFAULT)
+                .setInstanceID(ContainerUUID.UUID_LEGACY_VALUE)
+                .nextPersisted();
+
+        final CopyContentletForm copyContentletForm = new CopyContentletForm.Builder()
+                .pageId(page.getIdentifier())
+                .containerId(container.getIdentifier())
+                .relationType("1")
+                .contentId(contentlet.getIdentifier())
+                .variantId("")
+                .build();
+
+        final Language language = APILocator.getLanguageAPI().getLanguage(contentlet.getLanguageId());
+
+        final Contentlet contentletCopy = PageResourceHelper.getInstance().copyContentlet(copyContentletForm,
+                APILocator.systemUser(), PageMode.PREVIEW_MODE, language);
+
+        assertEquals(contentlet.getStringProperty("field1"), contentletCopy.getStringProperty("field1"));
+        assertEquals(contentlet.getStringProperty("field2"), contentletCopy.getStringProperty("field2"));
+
+        assertNotEquals(contentlet.getIdentifier(), contentletCopy.getIdentifier());
+        assertNotEquals(contentlet.getInode(), contentletCopy.getInode());
+    }
+
+    /**
+     * Method to test: {@link PageResourceHelper#copyContentlet(CopyContentletForm, User, PageMode, Language)}
+     * when: Try to copy a Content from a Page where the Multi_tree does not exist
+     * should: throw DoesNotExistException
+     *
+     * @throws DotDataException
+     * @throws DotSecurityException
+     */
+    @Test(expected = DoesNotExistException.class)
+    public void copyContentletThrowsDoesNotExistException() throws DotDataException, DotSecurityException {
+
+        final RandomString randomString = new RandomString();
+
+        final Field field_1 = new FieldDataGen()
+                .name("field1")
+                .velocityVarName("field1")
+                .type(TextField.class)
+                .next();
+
+        final ContentType contentType = new ContentTypeDataGen()
+                .field(field_1)
+                .nextPersisted();
+
+        final Contentlet contentlet = new ContentletDataGen(contentType.id())
+                .setProperty("field1", randomString.nextString())
+                .nextPersisted();
+
+        final Container container = new ContainerDataGen().nextPersisted();
+        final Host host = new SiteDataGen().nextPersisted();
+        final Template template = new TemplateDataGen()
+                .withContainer(container, ContainerUUID.UUID_LEGACY_VALUE)
+                .nextPersisted();
+
+        final HTMLPageAsset page = new HTMLPageDataGen(host, template).nextPersisted();
+
+        final CopyContentletForm copyContentletForm = new CopyContentletForm.Builder()
+                .pageId(page.getIdentifier())
+                .containerId(container.getIdentifier())
+                .relationType("1")
+                .contentId(contentlet.getIdentifier())
+                .build();
+
+        final Language language = APILocator.getLanguageAPI().getLanguage(contentlet.getLanguageId());
+
+        PageResourceHelper.getInstance().copyContentlet(copyContentletForm,
+                APILocator.systemUser(), PageMode.PREVIEW_MODE, language);
+    }
+
     /**
      * Method to test: {@link PageResourceHelper#copyContentlet(CopyContentletForm, User, PageMode, Language)}
      * when: Try to copy a Content from a Page where the Template is advanced and the Multi_tree has a