From 04c97f269fc732127c4c7e526b4952b312e62f16 Mon Sep 17 00:00:00 2001
From: Andreas Salzburger <asalzburger@gmail.com>
Date: Tue, 19 Nov 2024 15:41:31 +0100
Subject: [PATCH] make DD4hepGeometryContext not inhert from GeometryContext

---
 .../Plugins/DD4hep/DD4hepDetectorElement.hpp     |  8 +++++++-
 .../Plugins/DD4hep/DD4hepGeometryContext.hpp     |  7 +------
 Plugins/DD4hep/src/DD4hepDetectorElement.cpp     | 16 +++++++++++-----
 Plugins/DD4hep/src/DD4hepGeometryContext.cpp     |  2 +-
 4 files changed, 20 insertions(+), 13 deletions(-)

diff --git a/Plugins/DD4hep/include/Acts/Plugins/DD4hep/DD4hepDetectorElement.hpp b/Plugins/DD4hep/include/Acts/Plugins/DD4hep/DD4hepDetectorElement.hpp
index 94bd844c1a2..2b3ade4098e 100644
--- a/Plugins/DD4hep/include/Acts/Plugins/DD4hep/DD4hepDetectorElement.hpp
+++ b/Plugins/DD4hep/include/Acts/Plugins/DD4hep/DD4hepDetectorElement.hpp
@@ -9,6 +9,7 @@
 #pragma once
 
 #include "Acts/Geometry/GeometryContext.hpp"
+#include "Acts/Plugins/DD4hep/DD4hepGeometryContext.hpp"
 #include "Acts/Plugins/TGeo/TGeoDetectorElement.hpp"
 #include "Acts/Utilities/ThrowAssert.hpp"
 
@@ -42,7 +43,7 @@ class DD4hepDetectorElement : public TGeoDetectorElement {
   using DD4hepVolumeID = dd4hep::DDSegmentation::VolumeID;
 
   /// Broadcast the context type
-  using ContextType = GeometryContext;
+  using ContextType = DD4hepGeometryContext;
 
   /// Define a string based story
   using Store = std::map<std::string,
@@ -94,6 +95,11 @@ class DD4hepDetectorElement : public TGeoDetectorElement {
   /// @note This method enables dynamic geometry updates through the context
   const Transform3& transform(const GeometryContext& gctx) const final;
 
+  /// Return the nominal transform
+  ///
+  /// @note This method returns the nominal transform without any alignment
+  const Transform3& nominalTransform() const;
+
  private:
   /// DD4hep detector element
   dd4hep::DetElement m_detElement;
diff --git a/Plugins/DD4hep/include/Acts/Plugins/DD4hep/DD4hepGeometryContext.hpp b/Plugins/DD4hep/include/Acts/Plugins/DD4hep/DD4hepGeometryContext.hpp
index 89383428ace..b768a1837e3 100644
--- a/Plugins/DD4hep/include/Acts/Plugins/DD4hep/DD4hepGeometryContext.hpp
+++ b/Plugins/DD4hep/include/Acts/Plugins/DD4hep/DD4hepGeometryContext.hpp
@@ -9,7 +9,6 @@
 #pragma once
 
 #include "Acts/Definitions/Algebra.hpp"
-#include "Acts/Geometry/GeometryContext.hpp"
 
 namespace Acts {
 
@@ -19,14 +18,10 @@ class DD4hepDetectorElement;
 ///
 /// @brief DD4hep specific geometry context for alignment handling
 ///
-/// Extends the base GeometryContext to provide DD4hep-specific alignment
-/// capabilities. The context can be active or inactive, controlling whether
-/// alignment corrections should be applied.
-///
 /// @note This context is specifically designed to work with DD4hepDetectorElement
 /// and provides contextual transformations for alignment purposes.
 ///
-class DD4hepGeometryContext : public GeometryContext {
+class DD4hepGeometryContext {
  public:
   /// Explicit inactive constructor
   /// Creates an inactive geometry context that skips alignment corrections
diff --git a/Plugins/DD4hep/src/DD4hepDetectorElement.cpp b/Plugins/DD4hep/src/DD4hepDetectorElement.cpp
index 5d7722fd546..9b5cf463753 100644
--- a/Plugins/DD4hep/src/DD4hepDetectorElement.cpp
+++ b/Plugins/DD4hep/src/DD4hepDetectorElement.cpp
@@ -28,10 +28,16 @@ Acts::DD4hepDetectorElement::DD4hepDetectorElement(
 
 const Acts::Transform3& Acts::DD4hepDetectorElement::transform(
     const GeometryContext& gctx) const {
-  const Acts::DD4hepGeometryContext* dd4hepGtx =
-      gctx.maybeGet<DD4hepGeometryContext>();
-  if (dd4hepGtx != nullptr && dd4hepGtx->isActive()) {
-    return dd4hepGtx->contextualTransform(*this);
+  if (gctx.hasValue()) {
+    const DD4hepGeometryContext* dd4hepContext =
+        gctx.maybeGet<DD4hepGeometryContext>();
+    if (dd4hepContext != nullptr && dd4hepContext->isActive()) {
+      return dd4hepContext->contextualTransform(*this);
+    }
   }
-  return TGeoDetectorElement::m_transform;
+  return nominalTransform();
 }
+
+const Acts::Transform3& Acts::DD4hepDetectorElement::nominalTransform() const {
+  return TGeoDetectorElement::m_transform;
+};
diff --git a/Plugins/DD4hep/src/DD4hepGeometryContext.cpp b/Plugins/DD4hep/src/DD4hepGeometryContext.cpp
index a91a4030b7f..c052a8916c6 100644
--- a/Plugins/DD4hep/src/DD4hepGeometryContext.cpp
+++ b/Plugins/DD4hep/src/DD4hepGeometryContext.cpp
@@ -13,5 +13,5 @@
 const Acts::Transform3& Acts::DD4hepGeometryContext::contextualTransform(
     const Acts::DD4hepDetectorElement& dElement) const {
   // Use inactive context as the base transformation state
-  return dElement.transform(DD4hepGeometryContext::inactive());
+  return dElement.nominalTransform();
 }