From 026685ee48909cea2bddd06d0efb7d49dfb73acd Mon Sep 17 00:00:00 2001
From: JamesJ <13408010-JamesJCode@users.noreply.gitlab.com>
Date: Sat, 6 Apr 2024 18:44:23 +0100
Subject: [PATCH] Check a SHAPE_POLY_SET outline exists before attempting to
 get it by index

Fixes https://gitlab.com/kicad/code/kicad/-/issues/17687
---
 libs/kimath/src/geometry/shape.cpp | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/libs/kimath/src/geometry/shape.cpp b/libs/kimath/src/geometry/shape.cpp
index 7d9902d63e..768709594d 100644
--- a/libs/kimath/src/geometry/shape.cpp
+++ b/libs/kimath/src/geometry/shape.cpp
@@ -62,14 +62,26 @@ int SHAPE::GetClearance( const SHAPE* aOther ) const
     /// Triangles check three vertices each but for the outline, we only need one.
     /// These are also fractured, so we don't need to worry about holes
     if( Type() == SHAPE_TYPE::SH_POLY_SET )
-        a_shapes.push_back( &static_cast<const SHAPE_POLY_SET*>( this )->COutline( 0 ) );
+    {
+        const SHAPE_POLY_SET* polySet = static_cast<const SHAPE_POLY_SET*>( this );
+        if( polySet->OutlineCount() > 0 )
+            a_shapes.push_back( &polySet->COutline( 0 ) );
+    }
     else
+    {
         GetIndexableSubshapes( a_shapes );
+    }
 
     if( aOther->Type() == SHAPE_TYPE::SH_POLY_SET )
-        b_shapes.push_back( &static_cast<const SHAPE_POLY_SET*>( aOther )->COutline( 0 ) );
+    {
+        const SHAPE_POLY_SET* polySet = static_cast<const SHAPE_POLY_SET*>( aOther );
+        if( polySet->OutlineCount() > 0 )
+            b_shapes.push_back( &polySet->COutline( 0 ) );
+    }
     else
+    {
         aOther->GetIndexableSubshapes( b_shapes );
+    }
 
     if( GetIndexableSubshapeCount() == 0 )
         a_shapes.push_back( this );