From 64dcfb356c7336a68c2a5520939b87c909e9116b Mon Sep 17 00:00:00 2001
From: Paul Gessinger <hello@paulgessinger.com>
Date: Tue, 1 Oct 2024 10:11:08 +0200
Subject: [PATCH 1/2] feat(geo): Extent designated initialization

---
 Core/include/Acts/Geometry/Extent.hpp         | 27 +++++++++++++++++++
 Tests/UnitTests/Core/Geometry/ExtentTests.cpp | 11 ++++++++
 2 files changed, 38 insertions(+)

diff --git a/Core/include/Acts/Geometry/Extent.hpp b/Core/include/Acts/Geometry/Extent.hpp
index 698477744c0..9b9e00bc48b 100644
--- a/Core/include/Acts/Geometry/Extent.hpp
+++ b/Core/include/Acts/Geometry/Extent.hpp
@@ -74,6 +74,33 @@ struct ExtentEnvelope {
     }};
   }
 
+  /// Helper struct for designated initializer construction
+  struct Arguments {
+    Envelope x = zeroEnvelope;
+    Envelope y = zeroEnvelope;
+    Envelope z = zeroEnvelope;
+    Envelope r = zeroEnvelope;
+    Envelope phi = zeroEnvelope;
+    Envelope rPhi = zeroEnvelope;
+    Envelope h = zeroEnvelope;
+    Envelope eta = zeroEnvelope;
+    Envelope mag = zeroEnvelope;
+  };
+
+  /// Constructor using a helper struct for designated initializaion
+  /// @param args the arguments
+  constexpr explicit ExtentEnvelope(Arguments&& args) {
+    using enum BinningValue;
+    m_values[toUnderlying(binX)] = args.x;
+    m_values[toUnderlying(binY)] = args.y;
+    m_values[toUnderlying(binZ)] = args.z;
+    m_values[toUnderlying(binR)] = args.r;
+    m_values[toUnderlying(binPhi)] = args.phi;
+    m_values[toUnderlying(binH)] = args.h;
+    m_values[toUnderlying(binEta)] = args.eta;
+    m_values[toUnderlying(binMag)] = args.mag;
+  }
+
   /// Comparison operator between envelope sets
   /// @param lhs the left hand side
   /// @param rhs the right hand side
diff --git a/Tests/UnitTests/Core/Geometry/ExtentTests.cpp b/Tests/UnitTests/Core/Geometry/ExtentTests.cpp
index 80513a1d80b..e0913e273eb 100644
--- a/Tests/UnitTests/Core/Geometry/ExtentTests.cpp
+++ b/Tests/UnitTests/Core/Geometry/ExtentTests.cpp
@@ -176,6 +176,17 @@ BOOST_AUTO_TEST_CASE(ProtoSupportCaseTests) {
   BOOST_CHECK(volumeExtent.constrains(BinningValue::binR));
 }
 
+BOOST_AUTO_TEST_CASE(DesignatedInitializers) {
+  using enum BinningValue;
+  ExtentEnvelope exp;
+  exp[binX] = {1., 2.};
+  exp[binEta] = {-1., 1.};
+
+  ExtentEnvelope act{{.x = {1., 2.}, .eta = {-1., 1.}}};
+
+  BOOST_CHECK(exp == act);
+}
+
 BOOST_AUTO_TEST_SUITE_END()
 
 }  // namespace Acts::Test

From 8014d8cbe64d37686a4a2db3208a82857c94c494 Mon Sep 17 00:00:00 2001
From: Paul Gessinger <paul.gessinger@cern.ch>
Date: Wed, 2 Oct 2024 10:39:52 +0200
Subject: [PATCH 2/2] fix ambiguity

---
 Core/include/Acts/Geometry/Extent.hpp | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/Core/include/Acts/Geometry/Extent.hpp b/Core/include/Acts/Geometry/Extent.hpp
index 9b9e00bc48b..8728728996b 100644
--- a/Core/include/Acts/Geometry/Extent.hpp
+++ b/Core/include/Acts/Geometry/Extent.hpp
@@ -52,12 +52,6 @@ struct ExtentEnvelope {
     }
   }
 
-  /// Constructor from an array of envelopes
-  /// @param values the array of envelopes
-  constexpr explicit ExtentEnvelope(
-      const std::array<Envelope, numBinningValues()>& values)
-      : m_values(values) {}
-
   /// Static factory for a zero envelope
   /// @return the zero envelope
   constexpr static ExtentEnvelope Zero() {