From 595bf70d5d5bcc52bed298a73be19ccd24d476c9 Mon Sep 17 00:00:00 2001
From: Jon Evans <jon@craftyjon.com>
Date: Thu, 12 Jan 2023 09:16:11 -0500
Subject: [PATCH] Do not try to read from UI elements that haven't been
 initialized yet

Fixes https://gitlab.com/kicad/code/kicad/-/issues/13480
---
 pcbnew/board_stackup_manager/panel_board_stackup.cpp | 4 ++++
 pcbnew/dialogs/panel_setup_layers.cpp                | 5 ++++-
 pcbnew/dialogs/panel_setup_layers.h                  | 3 +++
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/pcbnew/board_stackup_manager/panel_board_stackup.cpp b/pcbnew/board_stackup_manager/panel_board_stackup.cpp
index ae9226d957..a816e6f88f 100644
--- a/pcbnew/board_stackup_manager/panel_board_stackup.cpp
+++ b/pcbnew/board_stackup_manager/panel_board_stackup.cpp
@@ -1315,6 +1315,10 @@ void PANEL_SETUP_BOARD_STACKUP::ImportSettingsFrom( BOARD* aBoard )
 
 void PANEL_SETUP_BOARD_STACKUP::OnLayersOptionsChanged( LSET aNewLayerSet )
 {
+    // Can be called spuriously from events before the layers page is even created
+    if( !m_panelLayers->IsInitialized() )
+        return;
+
     // First, verify the list of layers currently in stackup:
     // if it does not mach the list of layers set in PANEL_SETUP_LAYERS
     // rebuild the panel
diff --git a/pcbnew/dialogs/panel_setup_layers.cpp b/pcbnew/dialogs/panel_setup_layers.cpp
index ad8c302bf7..11248fa51a 100644
--- a/pcbnew/dialogs/panel_setup_layers.cpp
+++ b/pcbnew/dialogs/panel_setup_layers.cpp
@@ -128,7 +128,8 @@ PANEL_SETUP_LAYERS::PANEL_SETUP_LAYERS( PAGED_DIALOG* aParent, PCB_EDIT_FRAME* a
         PANEL_SETUP_LAYERS_BASE( aParent->GetTreebook() ),
         m_parentDialog( aParent ),
         m_frame( aFrame ),
-        m_physicalStackup( nullptr )
+        m_physicalStackup( nullptr ),
+        m_initialized( false )
 {
     m_pcb = aFrame->GetBoard();
 }
@@ -248,6 +249,8 @@ bool PANEL_SETUP_LAYERS::TransferDataToWindow()
     setMandatoryLayerCheckBoxes();
     setUserDefinedLayerCheckBoxes();
 
+    m_initialized = true;
+
     return true;
 }
 
diff --git a/pcbnew/dialogs/panel_setup_layers.h b/pcbnew/dialogs/panel_setup_layers.h
index e96aa7b0f4..b60f597d9e 100644
--- a/pcbnew/dialogs/panel_setup_layers.h
+++ b/pcbnew/dialogs/panel_setup_layers.h
@@ -91,6 +91,8 @@ public:
         m_physicalStackup = aPanel;
     }
 
+    bool IsInitialized() const { return m_initialized; }
+
 private:
 
     void setLayerCheckBox( int layer, bool isChecked );
@@ -132,6 +134,7 @@ private:
     PANEL_SETUP_BOARD_STACKUP* m_physicalStackup;
     BOARD*                     m_pcb;
     LSET                       m_enabledLayers;
+    bool                       m_initialized;
 };