From 45b2bce69849e7081323f072019c9fc9fa345270 Mon Sep 17 00:00:00 2001
From: Jeff Young <jeff@rokeby.ie>
Date: Thu, 18 Feb 2021 11:50:37 +0000
Subject: [PATCH] Cancel placement of via if user cancels layer selection.

Fixes https://gitlab.com/kicad/code/kicad/issues/7578
---
 pcbnew/router/router_tool.cpp |  3 +++
 pcbnew/sel_layer.cpp          | 11 +++++------
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/pcbnew/router/router_tool.cpp b/pcbnew/router/router_tool.cpp
index a704f0d812..4e2754231a 100644
--- a/pcbnew/router/router_tool.cpp
+++ b/pcbnew/router/router_tool.cpp
@@ -761,6 +761,9 @@ int ROUTER_TOOL::handleLayerSwitch( const TOOL_EVENT& aEvent, bool aForceVia )
         }
     }
 
+    if( targetLayer == UNDEFINED_LAYER )
+        return 0;
+
     // fixme: P&S supports more than one fixed layer pair. Update the dialog?
     sizes.ClearLayerPairs();
 
diff --git a/pcbnew/sel_layer.cpp b/pcbnew/sel_layer.cpp
index 6e8153abc0..e3d74633dc 100644
--- a/pcbnew/sel_layer.cpp
+++ b/pcbnew/sel_layer.cpp
@@ -222,8 +222,7 @@ void PCB_ONE_LAYER_SELECTOR::OnRightGridCellClick( wxGridEvent& event )
 }
 
 
-PCB_LAYER_ID PCB_BASE_FRAME::SelectOneLayer( PCB_LAYER_ID aDefaultLayer,
-                                             LSET aNotAllowedLayersMask,
+PCB_LAYER_ID PCB_BASE_FRAME::SelectOneLayer( PCB_LAYER_ID aDefaultLayer, LSET aNotAllowedLayersMask,
                                              wxPoint aDlgPosition )
 {
     PCB_ONE_LAYER_SELECTOR dlg( this, GetBoard(), aDefaultLayer, aNotAllowedLayersMask );
@@ -236,10 +235,10 @@ PCB_LAYER_ID PCB_BASE_FRAME::SelectOneLayer( PCB_LAYER_ID aDefaultLayer,
         dlg.SetPosition( aDlgPosition );
     }
 
-    dlg.ShowModal();
-
-    PCB_LAYER_ID layer = ToLAYER_ID( dlg.GetLayerSelection() );
-    return layer;
+    if( dlg.ShowModal() != wxID_CANCEL )
+        return ToLAYER_ID( dlg.GetLayerSelection() );
+    else
+        return UNDEFINED_LAYER;
 }