Export CSV: fixing null values in export due to improper location of …

…right-alignment role

fixed spelling in comment and added breaks to switch statements

Update src/library/basetracktablemodel.cpp

Rewording of comment improves clarity of M_FALLTHROUGH_INTENDED behaviour

Co-authored-by: ronso0 <ronso0@mixxx.org>

reverting unecessary breaks

src/library/basetracktablemodel.cpp

@@ -590,21 +590,9 @@ QVariant BaseTrackTableModel::roleValue(
             break;
         }
         M_FALLTHROUGH_INTENDED;
-    // Right align BPM, duraation and bitrate so big/small values can easily be
-    // spotted by length (number of digits)
-    case Qt::TextAlignmentRole: {
-        switch (field) {
-        case ColumnCache::COLUMN_LIBRARYTABLE_BPM:
-        case ColumnCache::COLUMN_LIBRARYTABLE_DURATION:
-        case ColumnCache::COLUMN_LIBRARYTABLE_BITRATE: {
-            // We need to cast to int due to a bug similar to
-            // https://bugreports.qt.io/browse/QTBUG-67582
-            return static_cast<int>(Qt::AlignVCenter | Qt::AlignRight);
-        }
-        default:
-            return QVariant(); // default AlignLeft for all other columns
-        }
-    }
+    // NOTE: for export we need to fall through to Qt::DisplayRole,
+    // so do not add any other role cases here, or the export
+    // will be empty
     case Qt::DisplayRole:
         switch (field) {
         case ColumnCache::COLUMN_LIBRARYTABLE_DURATION: {
@@ -873,6 +861,21 @@ QVariant BaseTrackTableModel::roleValue(
             return Qt::PartiallyChecked;
         }
     }
+    // Right align BPM, duration and bitrate so big/small values can easily be
+    // spotted by length (number of digits)
+    case Qt::TextAlignmentRole: {
+        switch (field) {
+        case ColumnCache::COLUMN_LIBRARYTABLE_BPM:
+        case ColumnCache::COLUMN_LIBRARYTABLE_DURATION:
+        case ColumnCache::COLUMN_LIBRARYTABLE_BITRATE: {
+            // We need to cast to int due to a bug similar to
+            // https://bugreports.qt.io/browse/QTBUG-67582
+            return static_cast<int>(Qt::AlignVCenter | Qt::AlignRight);
+        }
+        default:
+            return QVariant(); // default AlignLeft for all other columns
+        }
+    }
     default:
         DEBUG_ASSERT(!"unexpected role");
         break;