From 5319b068ec9ad02fd77b8424370abcf334ad204e Mon Sep 17 00:00:00 2001
From: Willem Deconinck <willem.deconinck@ecmwf.int>
Date: Thu, 12 Dec 2024 18:04:19 +0100
Subject: [PATCH] Fixup: workaround shared_ptr requiring a public constructor

---
 src/atlas/util/Factory.cc | 7 ++++---
 src/atlas/util/Factory.h  | 7 ++++++-
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/atlas/util/Factory.cc b/src/atlas/util/Factory.cc
index 869b1d4df..6af5227a6 100644
--- a/src/atlas/util/Factory.cc
+++ b/src/atlas/util/Factory.cc
@@ -8,11 +8,12 @@
  * nor does it submit to any jurisdiction.
  */
 
+#include "atlas/util/Factory.h"
+
 #include <iostream>
 
 #include "atlas/runtime/Exception.h"
 #include "atlas/runtime/Log.h"
-#include "atlas/util/Factory.h"
 
 // #define DEBUG_FACTORY_REGISTRATION
 
@@ -62,7 +63,7 @@ void FactoryRegistry::remove(const std::string& builder) {
     factories_.erase(builder);
 }
 
-FactoryRegistry::FactoryRegistry(const std::string& factory): factory_(factory) {
+FactoryRegistry::FactoryRegistry(const std::string& factory, FactoryRegistry::Private): factory_(factory) {
 #ifdef DEBUG_FACTORY_REGISTRATION
     std::cout << "Created " << factory << std::endl;
 #endif
@@ -115,7 +116,7 @@ FactoryBase::~FactoryBase() {
 std::shared_ptr<FactoryRegistry> FactoryRegistry::instance(const std::string& factory) {
     static std::map<std::string,std::shared_ptr<FactoryRegistry>> registries;
     if (registries.find(factory) == registries.end()) {
-        auto [it_pair, inserted] = registries.emplace(factory, new FactoryRegistry(factory));
+        auto [it_pair, inserted] = registries.emplace(factory, new FactoryRegistry(factory,Private()));
         return it_pair->second;
     }
     return registries.at(factory);
diff --git a/src/atlas/util/Factory.h b/src/atlas/util/Factory.h
index a0c4be047..d46d78c7a 100644
--- a/src/atlas/util/Factory.h
+++ b/src/atlas/util/Factory.h
@@ -27,7 +27,12 @@ class FactoryBase;
 
 class FactoryRegistry {
 private:
-    FactoryRegistry(const std::string& factory);
+    struct Private{ explicit Private() = default; };
+public:
+    // Constructor, essentially private because nobody can create an explicit Private object.
+    // Construction must happen via instance() function below
+    FactoryRegistry(const std::string& factory, Private);
+
     virtual ~FactoryRegistry();
 
 private: