fix: fix display logic for "Link" button on collection page

Author: vera

src/main/java/edu/harvard/iq/dataverse/DataversePage.java

@@ -207,18 +207,31 @@ public void setLinkMode(LinkMode linkMode) {
     }
 
     public boolean showLinkingPopup() {
-        String testquery = "";
-        if (session.getUser() == null) {
+        // Must be logged in
+        AuthenticatedUser au = getAuthenticatedUser();
+        if (au == null) {
             return false;
         }
         if (dataverse == null) {
             return false;
         }
-        if (query != null) {
-            testquery = query;
+
+        // If there is an active search query, that's all that matters (plus having permission on ANY collection)
+        if (query != null && !query.isEmpty()) {
+            List<Dataverse> permitted = permissionService.findPermittedCollections(dvRequestService.getDataverseRequest(), au, Permission.LinkDataverse);
+            return permitted != null && !permitted.isEmpty();
+        }
+
+        // Otherwise (no active search), check if there is at least one OTHER eligible collection
+        // Eligible means: not the current collection and not in the parent tree
+        // Technically, eligible also means "not already linked", but in that case, we show the Link button anyway and have the Link dialog display a message about all eligible collections already being linked
+        List<Dataverse> dvsWithLinkPermission = permissionService.findPermittedCollections(dvRequestService.getDataverseRequest(), au, Permission.LinkDataverse);
+        if (dvsWithLinkPermission != null && !dvsWithLinkPermission.isEmpty()) {
+            List<Dataverse> eligibleDataverses = dataverseService.removeUnlinkableDataverses(dvsWithLinkPermission, dataverse, false);
+            return !eligibleDataverses.isEmpty();
         }
 
-        return (dataverse.getOwner() != null || !testquery.isEmpty());
+        return false;
     }
 
     public void setupLinkingPopup (String popupSetting){

src/main/java/edu/harvard/iq/dataverse/DataverseServiceBean.java

@@ -551,28 +551,30 @@ public List<Dataverse> filterDataversesForLinking(String query, DataverseRequest
         return dataverseList;
     }
 
-    public List<Dataverse> removeUnlinkableDataverses(List<Dataverse> allWithPerms, DvObject dvo) {
+    public List<Dataverse> removeUnlinkableDataverses(List<Dataverse> allWithPerms, DvObject dvo, boolean removeAlreadyLinked) {
         List<Dataverse> dataverseList = new ArrayList<>();
         Dataset linkedDataset = null;
         Dataverse linkedDataverse = null;
-        List<Object> alreadyLinkeddv_ids;
-
-        if ((dvo instanceof Dataset)) {
-            linkedDataset = (Dataset) dvo;
-            alreadyLinkeddv_ids = em.createNativeQuery("SELECT linkingdataverse_id FROM datasetlinkingdataverse WHERE dataset_id = " + linkedDataset.getId()).getResultList();
-        } else {
-            linkedDataverse = (Dataverse) dvo;
-            alreadyLinkeddv_ids = em.createNativeQuery("SELECT linkingdataverse_id FROM dataverselinkingdataverse WHERE dataverse_id = " + linkedDataverse.getId()).getResultList();
-        }
 
         List<Dataverse> remove = new ArrayList<>();
 
-        if (alreadyLinkeddv_ids != null && !alreadyLinkeddv_ids.isEmpty()) {
-            alreadyLinkeddv_ids.stream().map((testDVId) -> this.find(testDVId)).forEachOrdered((removeIt) -> {
-                remove.add(removeIt);
-            });
+        if (removeAlreadyLinked) {
+            List<Object> alreadyLinkeddv_ids;
+
+            if ((dvo instanceof Dataset)) {
+                linkedDataset = (Dataset) dvo;
+                alreadyLinkeddv_ids = em.createNativeQuery("SELECT linkingdataverse_id FROM datasetlinkingdataverse WHERE dataset_id = " + linkedDataset.getId()).getResultList();
+            } else {
+                linkedDataverse = (Dataverse) dvo;
+                alreadyLinkeddv_ids = em.createNativeQuery("SELECT linkingdataverse_id FROM dataverselinkingdataverse WHERE dataverse_id = " + linkedDataverse.getId()).getResultList();
+            }
+
+            if (alreadyLinkeddv_ids != null && !alreadyLinkeddv_ids.isEmpty()) {
+                alreadyLinkeddv_ids.stream().map((testDVId) -> this.find(testDVId)).forEachOrdered((removeIt) -> {
+                    remove.add(removeIt);
+                });
+            }
         }
-        
 
         if (dvo instanceof Dataverse dataverse) {
             remove.add(dataverse);
@@ -596,8 +598,11 @@ public List<Dataverse> removeUnlinkableDataverses(List<Dataverse> allWithPerms,
 
         return dataverseList;
     }
-    
-  
+
+    public List<Dataverse> removeUnlinkableDataverses(List<Dataverse> allWithPerms, DvObject dvo) {
+        return removeUnlinkableDataverses(allWithPerms, dvo, true);
+    }
+
     public List<Dataverse> filterDataversesForUnLinking(String query, DataverseRequest req, Dataset dataset) {
         List<Object> alreadyLinkeddv_ids = em.createNativeQuery("SELECT linkingdataverse_id FROM datasetlinkingdataverse WHERE dataset_id = " + dataset.getId()).getResultList();
         List<Dataverse> dataverseList = new ArrayList<>();

src/main/webapp/dataverse.xhtml

@@ -501,7 +501,8 @@
                                     <!-- Edit/Publish Button Group -->
                                     <div class="btn-group" jsf:rendered="#{dataverseSession.user.authenticated and
                                                              (permissionsWrapper.canIssueUpdateDataverseCommand(DataversePage.dataverse)
-                                                             or permissionsWrapper.canIssuePublishDataverseCommand(DataversePage.dataverse))}">
+                                                             or permissionsWrapper.canIssuePublishDataverseCommand(DataversePage.dataverse)
+                                                             or DataversePage.showLinkingPopup())}">
                                             <!-- Publish Button -->
                                             <ui:fragment rendered="#{permissionsWrapper.canIssuePublishDataverseCommand(DataversePage.dataverse)}">
                                                 <button type="button" class="btn btn-default btn-access" onclick="PF('confirmation').show()"