From 91328cdeb56b2995f1b1fac9f7bc7410415de813 Mon Sep 17 00:00:00 2001
From: Phmonski <simon.cello@web.de>
Date: Wed, 22 Jul 2026 16:35:02 +0200
Subject: [PATCH] [HS3] Fix export of self_normalized flag

---
 roofit/hs3/src/JSONFactories_RooFitCore.cxx |  8 +-
 roofit/hs3/test/testRooFitHS3.cxx           | 82 +++++++++++++++++++++
 2 files changed, 88 insertions(+), 2 deletions(-)

diff --git a/roofit/hs3/src/JSONFactories_RooFitCore.cxx b/roofit/hs3/src/JSONFactories_RooFitCore.cxx
index 80c9e7afdc63b..5c6a93e6f13e7 100644
--- a/roofit/hs3/src/JSONFactories_RooFitCore.cxx
+++ b/roofit/hs3/src/JSONFactories_RooFitCore.cxx
@@ -1016,7 +1016,11 @@ bool importWrapperPdf(RooJSONFactoryWSTool *tool, const JSONNode &node)
 
    bool selfNormalized = false;
 
-   if (auto sn = node.find("selfNormalized"))
+   auto sn = node.find("self_normalized");
+   // ROOT previously exported this key without an underscore.
+   if (!sn)
+      sn = node.find("selfnormalized");
+   if (sn)
       selfNormalized = sn->val_bool();
 
    tool->wsEmplace<RooWrapperPdf>(name, *func, selfNormalized);
@@ -1039,7 +1043,7 @@ bool exportWrapperPdf(RooJSONFactoryWSTool *, const RooAbsArg *arg, JSONNode &no
 
    node["function"] << funcProxy->absArg()->GetName();
    if (pdf->selfNormalized())
-      node["selfnormalized"] << true;
+      node["self_normalized"] << true;
 
    return true;
 }
diff --git a/roofit/hs3/test/testRooFitHS3.cxx b/roofit/hs3/test/testRooFitHS3.cxx
index 2f2a71b7835c5..f146998fe1d98 100644
--- a/roofit/hs3/test/testRooFitHS3.cxx
+++ b/roofit/hs3/test/testRooFitHS3.cxx
@@ -35,6 +35,7 @@
 #include <RooStats/HistFactory/ParamHistFunc.h>
 #include <RooStats/HistFactory/FlexibleInterpVar.h>
 #include <RooStats/HistFactory/PiecewiseInterpolation.h>
+#include <RooWrapperPdf.h>
 #include <RooWorkspace.h>
 
 #include <cmath>
@@ -212,6 +213,17 @@ std::size_t countOccurrences(std::string_view haystack, std::string_view needle)
    return result;
 }
 
+std::string makeWrapperPdfJson(bool selfNormalized)
+{
+   RooRealVar x{"x", "x", 0.5, 0.0, 1.0};
+   RooFormulaVar function{"function", "1.0 + 0.0 * x", RooArgList{x}};
+   RooWrapperPdf pdf{"pdf", "pdf", function, selfNormalized};
+
+   RooWorkspace workspace;
+   workspace.import(pdf, RooFit::Silence());
+   return RooJSONFactoryWSTool{workspace}.exportJSONtoString();
+}
+
 // Asserts that exporting `ws` to HS3 throws and logs an error message containing `expectedReason`.
 void expectExportThrowsWithError(RooWorkspace &ws, std::string const &expectedReason)
 {
@@ -802,6 +814,76 @@ TEST(RooFitHS3, RooGenericPdf)
    EXPECT_EQ(status, 0);
 }
 
+TEST(RooFitHS3, RooWrapperPdfSelfNormalizedRoundTrip)
+{
+   const std::string json = makeWrapperPdfJson(true);
+   EXPECT_NE(json.find("\"self_normalized\":true"), std::string::npos) << json;
+   EXPECT_EQ(json.find("\"selfnormalized\""), std::string::npos) << json;
+   EXPECT_EQ(json.find("\"selfNormalized\""), std::string::npos) << json;
+
+   RooWorkspace imported;
+   ASSERT_TRUE(RooJSONFactoryWSTool{imported}.importJSONfromString(json));
+   auto *pdf = dynamic_cast<RooWrapperPdf *>(imported.pdf("pdf"));
+   ASSERT_NE(pdf, nullptr);
+   EXPECT_TRUE(pdf->selfNormalized());
+
+   const std::string defaultJson = makeWrapperPdfJson(false);
+   EXPECT_EQ(defaultJson.find("self_normalized"), std::string::npos) << defaultJson;
+
+   RooWorkspace importedDefault;
+   ASSERT_TRUE(RooJSONFactoryWSTool{importedDefault}.importJSONfromString(defaultJson));
+   auto *defaultPdf = dynamic_cast<RooWrapperPdf *>(importedDefault.pdf("pdf"));
+   ASSERT_NE(defaultPdf, nullptr);
+   EXPECT_FALSE(defaultPdf->selfNormalized());
+}
+
+TEST(RooFitHS3, RooWrapperPdfSelfNormalizedLegacyCompatibility)
+{
+   std::string legacyJson = makeWrapperPdfJson(true);
+   const auto canonicalPos = legacyJson.find("self_normalized");
+   ASSERT_NE(canonicalPos, std::string::npos) << legacyJson;
+   legacyJson.replace(canonicalPos, std::string{"self_normalized"}.size(), "selfnormalized");
+
+   RooWorkspace imported;
+   ASSERT_TRUE(RooJSONFactoryWSTool{imported}.importJSONfromString(legacyJson));
+   auto *pdf = dynamic_cast<RooWrapperPdf *>(imported.pdf("pdf"));
+   ASSERT_NE(pdf, nullptr);
+   EXPECT_TRUE(pdf->selfNormalized());
+
+   const std::string canonicalJson = RooJSONFactoryWSTool{imported}.exportJSONtoString();
+   EXPECT_NE(canonicalJson.find("\"self_normalized\":true"), std::string::npos) << canonicalJson;
+   EXPECT_EQ(canonicalJson.find("\"selfnormalized\""), std::string::npos) << canonicalJson;
+}
+
+TEST(RooFitHS3, RooWrapperPdfSelfNormalizedCanonicalKeyTakesPrecedence)
+{
+   std::string json = makeWrapperPdfJson(true);
+   const std::string canonicalField = "\"self_normalized\":true";
+   const auto canonicalPos = json.find(canonicalField);
+   ASSERT_NE(canonicalPos, std::string::npos) << json;
+   json.replace(canonicalPos, canonicalField.size(), "\"self_normalized\":false,\"selfnormalized\":true");
+
+   RooWorkspace imported;
+   ASSERT_TRUE(RooJSONFactoryWSTool{imported}.importJSONfromString(json));
+   auto *pdf = dynamic_cast<RooWrapperPdf *>(imported.pdf("pdf"));
+   ASSERT_NE(pdf, nullptr);
+   EXPECT_FALSE(pdf->selfNormalized());
+}
+
+TEST(RooFitHS3, RooWrapperPdfSelfNormalizedCamelCaseKeyIsIgnored)
+{
+   std::string json = makeWrapperPdfJson(true);
+   const auto canonicalPos = json.find("self_normalized");
+   ASSERT_NE(canonicalPos, std::string::npos) << json;
+   json.replace(canonicalPos, std::string{"self_normalized"}.size(), "selfNormalized");
+
+   RooWorkspace imported;
+   ASSERT_TRUE(RooJSONFactoryWSTool{imported}.importJSONfromString(json));
+   auto *pdf = dynamic_cast<RooWrapperPdf *>(imported.pdf("pdf"));
+   ASSERT_NE(pdf, nullptr);
+   EXPECT_FALSE(pdf->selfNormalized());
+}
+
 TEST(RooFitHS3, GenericExpressionCleanup)
 {
    RooRealVar x{"x", "x", 0.5, -1.0, 1.0};