Fix T96429: outliner tooltip inconsistent with behavior when linking collections

Previously, it would show "Link inside collection" but move between collections
instead in some cases. Additionally there was no tooltip for the "Link before/
after/between collections" case.

Behavior and tooltip should now be consistent in all cases.

Differential Revision: https://developer.blender.org/D15237

1 files changed, 40 insertions, 29 deletions

diff --git a/source/blender/editors/space_outliner/outliner_dragdrop.cc b/source/blender/editors/space_outliner/outliner_dragdrop.cc
index e20958c1b1e..7782da9d762 100644
--- a/source/blender/editors/space_outliner/outliner_dragdrop.cc
+++ b/source/blender/editors/space_outliner/outliner_dragdrop.cc
@@ -1157,9 +1157,6 @@ static bool collection_drop_init(
   /* Get collection to drag out of. */
   ID *parent = drag_id->from_parent;
   Collection *from_collection = collection_parent_from_ID(parent);
-  if (is_link) {
-    from_collection = nullptr;
-  }
 
   /* Currently this should not be allowed, cannot edit items in an override of a Collection. */
   if (from_collection != nullptr && ID_IS_OVERRIDE_LIBRARY(from_collection)) {
@@ -1201,25 +1198,19 @@ static bool collection_drop_poll(bContext *C, wmDrag *drag, const wmEvent *event
       collection_drop_init(C, drag, event->xy, event->modifier & KM_CTRL, &data)) {
     TreeElement *te = data.te;
     TreeStoreElem *tselem = TREESTORE(te);
-    if (!data.from || event->modifier & KM_CTRL) {
-      tselem->flag |= TSE_DRAG_INTO;
-      changed = true;
-    }
-    else {
-      switch (data.insert_type) {
-        case TE_INSERT_BEFORE:
-          tselem->flag |= TSE_DRAG_BEFORE;
-          changed = true;
-          break;
-        case TE_INSERT_AFTER:
-          tselem->flag |= TSE_DRAG_AFTER;
-          changed = true;
-          break;
-        case TE_INSERT_INTO: {
-          tselem->flag |= TSE_DRAG_INTO;
-          changed = true;
-          break;
-        }
+    switch (data.insert_type) {
+      case TE_INSERT_BEFORE:
+        tselem->flag |= TSE_DRAG_BEFORE;
+        changed = true;
+        break;
+      case TE_INSERT_AFTER:
+        tselem->flag |= TSE_DRAG_AFTER;
+        changed = true;
+        break;
+      case TE_INSERT_INTO: {
+        tselem->flag |= TSE_DRAG_INTO;
+        changed = true;
+        break;
       }
     }
     if (changed) {
@@ -1244,28 +1235,48 @@ static char *collection_drop_tooltip(bContext *C,
   CollectionDrop data;
   if (event && ((event->modifier & KM_SHIFT) == 0) &&
       collection_drop_init(C, drag, xy, event->modifier & KM_CTRL, &data)) {
-    TreeElement *te = data.te;
-    if (!data.from || event->modifier & KM_CTRL) {
-      return BLI_strdup(TIP_("Link inside Collection"));
+    const bool is_link = !data.from || (event->modifier & KM_CTRL);
+
+    /* Test if we are moving within same parent collection. */
+    bool same_level = false;
+    LISTBASE_FOREACH (CollectionParent *, parent, &data.to->parents) {
+      if (data.from == parent->collection) {
+        same_level = true;
+      }
     }
+
+    /* Tooltips when not moving directly into another collection i.e. mouse on border of
+     * collections. Later we will decide which tooltip to return. */
+    const bool tooltip_link = (is_link && !same_level);
+    const char *tooltip_before = tooltip_link ? TIP_("Link before collection") :
+                                                TIP_("Move before collection");
+    const char *tooltip_between = tooltip_link ? TIP_("Link between collections") :
+                                                 TIP_("Move between collections");
+    const char *tooltip_after = tooltip_link ? TIP_("Link after collection") :
+                                               TIP_("Move after collection");
+
+    TreeElement *te = data.te;
     switch (data.insert_type) {
       case TE_INSERT_BEFORE:
         if (te->prev && outliner_is_collection_tree_element(te->prev)) {
-          return BLI_strdup(TIP_("Move between collections"));
+          return BLI_strdup(tooltip_between);
         }
         else {
-          return BLI_strdup(TIP_("Move before collection"));
+          return BLI_strdup(tooltip_before);
         }
         break;
       case TE_INSERT_AFTER:
         if (te->next && outliner_is_collection_tree_element(te->next)) {
-          return BLI_strdup(TIP_("Move between collections"));
+          return BLI_strdup(tooltip_between);
         }
         else {
-          return BLI_strdup(TIP_("Move after collection"));
+          return BLI_strdup(tooltip_after);
         }
         break;
       case TE_INSERT_INTO: {
+        if (is_link) {
+          return BLI_strdup(TIP_("Link inside collection"));
+        }
 
         /* Check the type of the drag IDs to avoid the incorrect "Shift to parent"
          * for collections. Checking the type of the first ID works fine here since