fix in MMAP navigation when traveling to portal node

src/server/game/World/ClientlessTravelMgr.cpp

@@ -125,10 +125,22 @@ bool ClientlessTravelMgr::AnalyzePath(
         diagnostics.FinalDistance = diagnostics.DirectDistance;
 
     uint32 const pathType = diagnostics.PathType;
+    // VCORE_C814A_NAVIGATION_FIX: narrowly accept a short incomplete MMAP path
+    // only when its actual points reach the target without unsafe segments.
+    bool const shortEndReached =
+        diagnostics.Calculated &&
+        (pathType & uint32(PATHFIND_INCOMPLETE)) != 0 &&
+        (pathType & uint32(PATHFIND_NOPATH)) == 0 &&
+        diagnostics.PointCount >= 2 &&
+        diagnostics.DirectDistance <= 25.0f &&
+        diagnostics.PathLength <= 40.0f &&
+        diagnostics.FinalDistance <= 0.25f &&
+        diagnostics.MaxSegmentLength <= 6.0f &&
+        diagnostics.MaxZDelta <= 4.0f;
     diagnostics.Complete =
         diagnostics.Calculated &&
         (pathType & uint32(PATHFIND_NOPATH)) == 0 &&
-        (pathType & uint32(PATHFIND_INCOMPLETE)) == 0;
+        ((pathType & uint32(PATHFIND_INCOMPLETE)) == 0 || shortEndReached);
 
     auto addReason = [&](char const* reason)
     {
@@ -196,6 +208,19 @@ bool ClientlessTravelMgr::LaunchPath(Player* player, TravelRecord& record)
 
     Position const& target = record.Status.Target;
 
+    // VCORE_C814A_NAVIGATION_FIX: an already reached node is not a failed spline.
+    if (Distance3D(player->GetPositionX(), player->GetPositionY(), player->GetPositionZ(),
+            target.GetPositionX(), target.GetPositionY(), target.GetPositionZ()) <= ARRIVAL_DISTANCE)
+    {
+        record.Status.State = ClientlessTravelState::Arrived;
+        record.Status.RemainingDistance = 0.0f;
+        record.Status.NoProgressMs = 0;
+        TC_LOG_INFO("server.adventurebot.navigation",
+            "NAV_ALREADY_ARRIVED guid=%u name='%s' map=%u",
+            player->GetGUID().GetCounter(), player->GetName().c_str(), player->GetMapId());
+        return true;
+    }
+
     AnalyzePath(player, target, record.Status.Path);
     ClientlessPathDiagnostics const& nav = record.Status.Path;
     record.Status.NavSequence = _nextNavSequence++;
@@ -245,9 +270,38 @@ bool ClientlessTravelMgr::LaunchPath(Player* player, TravelRecord& record)
 
     auto const& points = path.GetPath();
     uint32 const executionType = uint32(path.GetPathType());
+    // VCORE_C814A_NAVIGATION_FIX: confirm the execution path independently.
+    float executionLength = 0.0f;
+    float executionMaxSegment = 0.0f;
+    float executionMaxZ = 0.0f;
+    for (std::size_t i = 1; i < points.size(); ++i)
+    {
+        float const segment = Distance3D(points[i-1].x, points[i-1].y, points[i-1].z,
+            points[i].x, points[i].y, points[i].z);
+        executionLength += segment;
+        executionMaxSegment = std::max(executionMaxSegment, segment);
+        executionMaxZ = std::max(executionMaxZ, std::fabs(points[i].z - points[i-1].z));
+    }
+    float const executionFinalDistance = points.empty() ? nav.DirectDistance :
+        Distance3D(points.back().x, points.back().y, points.back().z,
+            target.GetPositionX(), target.GetPositionY(), target.GetPositionZ());
+    bool const executionShortEndReached =
+        (executionType & uint32(PATHFIND_INCOMPLETE)) != 0 &&
+        (executionType & uint32(PATHFIND_NOPATH)) == 0 &&
+        points.size() >= 2 &&
+        nav.DirectDistance <= 25.0f &&
+        executionLength <= 40.0f &&
+        executionFinalDistance <= 0.25f &&
+        executionMaxSegment <= 6.0f &&
+        executionMaxZ <= 4.0f;
+    if (executionShortEndReached)
+        TC_LOG_INFO("server.adventurebot.navigation",
+            "NAV_SHORT_INCOMPLETE_ACCEPT guid=%u name='%s' path=%.2f final=%.2f",
+            player->GetGUID().GetCounter(), player->GetName().c_str(),
+            executionLength, executionFinalDistance);
     if (points.size() < 2 ||
         (executionType & uint32(PATHFIND_NOPATH)) != 0 ||
-        (executionType & uint32(PATHFIND_INCOMPLETE)) != 0)
+        ((executionType & uint32(PATHFIND_INCOMPLETE)) != 0 && !executionShortEndReached))
     {
         record.Status.State = ClientlessTravelState::PathRejected;
         TC_LOG_WARN("server.adventurebot.navigation",