From f56fcb0a14cdd8cd50f2c102288a6476f8d6f7d9 Mon Sep 17 00:00:00 2001
From: Seth Hillbrand <seth@kipro-pcb.com>
Date: Mon, 13 Feb 2023 11:18:04 -0800
Subject: [PATCH] Better handling of vertex sorting

Nominally, the zcode of a vertex is unique.  This is not 100% true,
however, as we must interlace two 32-bit numbers into a single 32-bit
number.  Sorting needs to account for the possibility that the zcode
will be the same while other elements of the vertex are different.  This
commit fixes the broken boolean logic to more clearly handle these cases

Fixes https://gitlab.com/kicad/code/kicad/issues/13867

(cherry picked from commit e7fe69b97ff558c208c6ef35d4f3270277cbb61d)
---
 .../include/geometry/polygon_triangulation.h       | 11 ++++++++++-
 pcbnew/drc/drc_test_provider_connection_width.cpp  | 14 ++++++++++----
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/libs/kimath/include/geometry/polygon_triangulation.h b/libs/kimath/include/geometry/polygon_triangulation.h
index ccb7a1acf1..788d8d3255 100644
--- a/libs/kimath/include/geometry/polygon_triangulation.h
+++ b/libs/kimath/include/geometry/polygon_triangulation.h
@@ -210,7 +210,16 @@ private:
 
             std::sort( queue.begin(), queue.end(), []( const Vertex* a, const Vertex* b )
             {
-                return a->z < b->z;
+                if( a->z != b->z )
+                    return a->z < b->z;
+
+                if( a->x != b->x )
+                    return a->x < b->x;
+
+                if( a->y != b->y )
+                    return a->y < b->y;
+
+                return a->i < b->i;
             } );
 
             Vertex* prev_elem = nullptr;
diff --git a/pcbnew/drc/drc_test_provider_connection_width.cpp b/pcbnew/drc/drc_test_provider_connection_width.cpp
index a51d865553..b72d856e75 100644
--- a/pcbnew/drc/drc_test_provider_connection_width.cpp
+++ b/pcbnew/drc/drc_test_provider_connection_width.cpp
@@ -252,10 +252,16 @@ private:
 
             std::sort( queue.begin(), queue.end(), []( const Vertex* a, const Vertex* b )
             {
-                return a->z < b->z || ( a->z == b->z
-                            && ( ( a->x < b->x )
-                              || ( a->y < b->y )
-                              || ( a->i < b->i ) ) );
+                if( a->z != b->z )
+                    return a->z < b->z;
+
+                if( a->x != b->x )
+                    return a->x < b->x;
+
+                if( a->y != b->y )
+                    return a->y < b->y;
+
+                return a->i < b->i;
             } );
 
             Vertex* prev_elem = nullptr;