Don't crash when adding new columns to a stretch header view.

Fixes issue 2562

src/playlist/playlistview.cpp

@@ -89,6 +89,7 @@ PlaylistView::PlaylistView(QWidget *parent)
     setting_initial_header_layout_(false),
     upgrading_from_qheaderview_(false),
     read_only_settings_(true),
+    upgrading_from_version_(-1),
     glow_enabled_(true),
     currently_glowing_(false),
     glow_intensity_step_(0),
@@ -255,6 +256,8 @@ void PlaylistView::LoadGeometry() {
   // New columns that we add are visible by default if the user has upgraded
   // Clementine.  Hide them again here
   const int state_version = settings.value("state_version", 0).toInt();
+  upgrading_from_version_ = state_version;
+  
   if (state_version < 1) {
     header_->HideSection(Playlist::Column_Rating);
     header_->HideSection(Playlist::Column_PlayCount);
@@ -267,9 +270,6 @@ void PlaylistView::LoadGeometry() {
   if (state_version < 3) {
     header_->HideSection(Playlist::Column_Comment);
   }
-  if (state_version < 4) {
-    header_->SetColumnWidth(Playlist::Column_Source, 0.05);
-  }
 
   // Make sure at least one column is visible
   bool all_hidden = true;
@@ -898,6 +898,13 @@ void PlaylistView::ReloadSettings() {
     setting_initial_header_layout_ = false;
   }
   
+  if (upgrading_from_version_ != -1) {
+    if (upgrading_from_version_ < 4) {
+      header_->SetColumnWidth(Playlist::Column_Source, 0.05);
+    }
+    upgrading_from_version_ = -1;
+  }
+
   column_alignment_ = s.value("column_alignments").value<ColumnAlignmentMap>();
   if (column_alignment_.isEmpty()) {
     column_alignment_ = DefaultColumnAlignment();

src/playlist/playlistview.h

@@ -168,6 +168,7 @@ class PlaylistView : public QTreeView {
   bool setting_initial_header_layout_;
   bool upgrading_from_qheaderview_;
   bool read_only_settings_;
+  int upgrading_from_version_;
 
   bool background_enabled_;
 

src/widgets/stretchheaderview.cpp

@@ -271,6 +271,11 @@ bool StretchHeaderView::RestoreState(const QByteArray& data) {
     }
   }
   
+  // Have we added more columns since the last time?
+  while (column_widths_.count() < count()) {
+    column_widths_ << 0;
+  }
+
   if (stretch_enabled_) {
     // In stretch mode, we've already set the proportional column widths so apply
     // them now.