From 5e850911c57587ae79a111cc545ce8bcff453051 Mon Sep 17 00:00:00 2001
From: Seth Hillbrand <seth@kipro-pcb.com>
Date: Fri, 29 Mar 2024 09:49:43 -0700
Subject: [PATCH] When dragging a via, we need to get all obstacles

The clearance epsilon should not be used to limit which force elements
we return in the query.  Otherwise, we can drag elements into a
DRC-violating space

Fixes https://gitlab.com/kicad/code/kicad/-/issues/16293
---
 pcbnew/router/pns_item.cpp |  3 +++
 pcbnew/router/pns_node.cpp | 14 ++++++++++----
 pcbnew/router/pns_node.h   | 13 +++++++++++--
 pcbnew/router/pns_via.cpp  |  7 ++++++-
 4 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/pcbnew/router/pns_item.cpp b/pcbnew/router/pns_item.cpp
index 042fe0e497..c42f4cfe9e 100644
--- a/pcbnew/router/pns_item.cpp
+++ b/pcbnew/router/pns_item.cpp
@@ -192,6 +192,9 @@ bool ITEM::collideSimple( const ITEM* aHead, const NODE* aNode,
     }
     else
     {
+        if( aCtx && !aCtx->options.m_useClearanceEpsilon )
+            clearanceEpsilon = 0;
+
         clearance = aNode->GetClearance( this, aHead, aCtx ? aCtx->options.m_useClearanceEpsilon
                                                            : false );
     }
diff --git a/pcbnew/router/pns_node.cpp b/pcbnew/router/pns_node.cpp
index 3bec2d8b1c..cb71b95cd0 100644
--- a/pcbnew/router/pns_node.cpp
+++ b/pcbnew/router/pns_node.cpp
@@ -409,12 +409,18 @@ NODE::OPT_OBSTACLE NODE::CheckColliding( const ITEM_SET& aSet, int aKindMask )
 
 NODE::OPT_OBSTACLE NODE::CheckColliding( const ITEM* aItemA, int aKindMask )
 {
-    OBSTACLES obs;
     COLLISION_SEARCH_OPTIONS opts;
 
     opts.m_kindMask = aKindMask;
     opts.m_limitCount = 1;
 
+    return CheckColliding( aItemA, opts );
+}
+
+NODE::OPT_OBSTACLE NODE::CheckColliding( const ITEM* aItemA, const COLLISION_SEARCH_OPTIONS& aOpts )
+{
+    OBSTACLES obs;
+
     if( aItemA->Kind() == ITEM::LINE_T )
     {
         int n = 0;
@@ -428,7 +434,7 @@ NODE::OPT_OBSTACLE NODE::CheckColliding( const ITEM* aItemA, int aKindMask )
             // Disabling the cache will lead to slowness.
 
             const SEGMENT s( *line, l.CSegment( i ) );
-            n += QueryColliding( &s, obs, opts );
+            n += QueryColliding( &s, obs, aOpts );
 
             if( n )
                 return OPT_OBSTACLE( *obs.begin() );
@@ -436,13 +442,13 @@ NODE::OPT_OBSTACLE NODE::CheckColliding( const ITEM* aItemA, int aKindMask )
 
         if( line->EndsWithVia() )
         {
-            n += QueryColliding( &line->Via(), obs, opts );
+            n += QueryColliding( &line->Via(), obs, aOpts );
 
             if( n )
                 return OPT_OBSTACLE( *obs.begin() );
         }
     }
-    else if( QueryColliding( aItemA, obs, opts ) > 0 )
+    else if( QueryColliding( aItemA, obs, aOpts ) > 0 )
     {
         return OPT_OBSTACLE( *obs.begin() );
     }
diff --git a/pcbnew/router/pns_node.h b/pcbnew/router/pns_node.h
index c2b1fc4433..da6eaceaad 100644
--- a/pcbnew/router/pns_node.h
+++ b/pcbnew/router/pns_node.h
@@ -279,8 +279,7 @@ public:
      * starting point.
      *
      * @param aLine the item to find collisions with
-     * @param aKindMask mask of obstacle types to take into account
-     * @param aRestrictedSet is an optional set of items that should be considered as obstacles
+     * @param aOpts options for the search
      * @return the obstacle, if found, otherwise empty.
      */
     OPT_OBSTACLE NearestObstacle( const LINE* aLine,
@@ -307,6 +306,16 @@ public:
      */
     OPT_OBSTACLE CheckColliding( const ITEM_SET&  aSet, int aKindMask = ITEM::ANY_T );
 
+    /**
+     * Check if the item collides with anything else in the world, and if found, returns the
+     * obstacle.
+     *
+     * @param aItem the item to find collisions with
+     * @param aOpts options for the search
+     * @return the obstacle, if found, otherwise empty.
+     */
+    OPT_OBSTACLE CheckColliding( const ITEM* aItem, const COLLISION_SEARCH_OPTIONS& aOpts );
+
     /**
      * Find all items that contain the point \a aPoint.
      *
diff --git a/pcbnew/router/pns_via.cpp b/pcbnew/router/pns_via.cpp
index dfc85a4842..169d8ebb79 100644
--- a/pcbnew/router/pns_via.cpp
+++ b/pcbnew/router/pns_via.cpp
@@ -61,7 +61,12 @@ bool VIA::PushoutForce( NODE* aNode, const VECTOR2I& aDirection, VECTOR2I& aForc
 
     while( iter < aMaxIterations )
     {
-        NODE::OPT_OBSTACLE obs = aNode->CheckColliding( &mv, aCollisionMask );
+        COLLISION_SEARCH_OPTIONS opt;
+        opt.m_limitCount = 1;
+        opt.m_kindMask = aCollisionMask;
+        opt.m_useClearanceEpsilon = false;
+
+        NODE::OPT_OBSTACLE obs = aNode->CheckColliding( &mv, opt );
 
         if( !obs )
             break;