From 5df99f529dff9df4504136c3a53be4be3f5b1d82 Mon Sep 17 00:00:00 2001
From: Vincenzo Eduardo Padulano <vincenzo.eduardo.padulano@cern.ch>
Date: Wed, 10 Jun 2026 11:16:31 +0200
Subject: [PATCH] [df] Request dictionary for mergeable THnSparseD

This allows proper serialization in case of calling HistoNSparseD operation in
distributed mode.
---
 tree/dataframe/inc/LinkDef.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tree/dataframe/inc/LinkDef.h b/tree/dataframe/inc/LinkDef.h
index 7c13310367149..1db345a0fe230 100644
--- a/tree/dataframe/inc/LinkDef.h
+++ b/tree/dataframe/inc/LinkDef.h
@@ -54,6 +54,7 @@
 #pragma link C++ class ROOT::Detail::RDF::RMergeableValue<TH2D>+;
 #pragma link C++ class ROOT::Detail::RDF::RMergeableValue<TH3D>+;
 #pragma link C++ class ROOT::Detail::RDF::RMergeableValue<THnD>+;
+#pragma link C++ class ROOT::Detail::RDF::RMergeableValue<THnSparseD>+;
 #pragma link C++ class ROOT::Detail::RDF::RMergeableValue<TGraph>+;
 #pragma link C++ class ROOT::Detail::RDF::RMergeableValue<TGraphAsymmErrors>+;
 #pragma link C++ class ROOT::Detail::RDF::RMergeableValue<TStatistic>+;