From d72798d7ddf8e6d8cec53af4e42cf970aa2fe256 Mon Sep 17 00:00:00 2001
From: Anton Alkin <anton.alkin@cern.ch>
Date: Tue, 1 Apr 2025 11:14:42 +0200
Subject: [PATCH] DPL Analysis: fix combinations generator parsing in analysis
 task

---
 .../Core/include/Framework/AnalysisManagers.h      |  4 +---
 .../Core/include/Framework/GroupedCombinations.h   | 14 +++++---------
 Framework/Core/test/test_Concepts.cxx              |  3 +++
 3 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/Framework/Core/include/Framework/AnalysisManagers.h b/Framework/Core/include/Framework/AnalysisManagers.h
index ccabbd7a0a197..733e91706b4a8 100644
--- a/Framework/Core/include/Framework/AnalysisManagers.h
+++ b/Framework/Core/include/Framework/AnalysisManagers.h
@@ -495,16 +495,14 @@ bool initializeCache(ProcessingContext& context, T& cache)
 
 /// Combinations handling
 template <typename C, typename TG, typename... Ts>
-  requires(!is_combinations_generator<C>)
 void setGroupedCombination(C&, TG&, Ts&...)
 {
 }
 
 template <is_combinations_generator C, typename TG, typename... Ts>
-  requires((sizeof...(Ts) > 0) && (C::compatible(framework::pack<Ts...>{})))
 static void setGroupedCombination(C& comb, TG& grouping, std::tuple<Ts...>& associated)
 {
-  if constexpr (std::same_as<typename C::g_t, TG>) {
+  if constexpr (std::same_as<typename C::g_t, std::decay_t<TG>>) {
     comb.setTables(grouping, associated);
   }
 }
diff --git a/Framework/Core/include/Framework/GroupedCombinations.h b/Framework/Core/include/Framework/GroupedCombinations.h
index bdbddee871baa..b0a6c9e658a10 100644
--- a/Framework/Core/include/Framework/GroupedCombinations.h
+++ b/Framework/Core/include/Framework/GroupedCombinations.h
@@ -48,17 +48,12 @@ expressions::BindingNode getMatchingIndexNode()
 }
 
 template <typename T1, typename GroupingPolicy, typename BP, typename G, typename... As>
+  requires(sizeof...(As) > 0)
 struct GroupedCombinationsGenerator {
   using grouping_policy_t = GroupingPolicy;
   using g_t = G;
   using associated_pack_t = framework::pack<As...>;
 
-  template <typename... Ts>
-  static consteval bool compatible(framework::pack<Ts...> p)
-  {
-    return (framework::has_type<As>(p) && ...);
-  }
-
   using GroupedIteratorType = pack_to_tuple_t<interleaved_pack_t<repeated_type_pack_t<typename G::iterator, sizeof...(As)>, pack<As...>>>;
 
   struct GroupedIterator : public GroupingPolicy {
@@ -241,10 +236,11 @@ struct GroupedCombinationsGenerator {
 };
 
 template <typename T>
-concept is_combinations_generator = requires(T t) {
+concept is_combinations_generator = requires(T t, typename T::g_t const& g, pack_to_tuple_t<typename T::associated_pack_t>& a) {
   typename T::GroupedIterator;
-  &T::begin;
-  &T::end;
+  t.setTables(g, a);
+  { t.begin() } -> std::same_as<typename T::iterator>;
+  { t.end() } -> std::same_as<typename T::iterator>;
 };
 
 // Aliases for 2-particle correlations
diff --git a/Framework/Core/test/test_Concepts.cxx b/Framework/Core/test/test_Concepts.cxx
index 00ad931828b44..4bf4f977ec3a8 100644
--- a/Framework/Core/test/test_Concepts.cxx
+++ b/Framework/Core/test/test_Concepts.cxx
@@ -161,4 +161,7 @@ TEST_CASE("IdentificationConcepts")
   // Expressions
   expressions::Filter f = o2::aod::track::pt > 1.0f;
   REQUIRE(expressions::is_filter<decltype(f)>);
+
+  using C = SameKindPair<aod::Collisions, aod::Tracks, ColumnBinningPolicy<aod::collision::PosZ>>;
+  REQUIRE(is_combinations_generator<C>);
 }