DPL Analysis: protect aod-spawner from empty tables

Author: aalkin

Framework/Core/include/Framework/ASoA.h

@@ -34,7 +34,6 @@
 #include <concepts>
 #include <cstring>
 #include <gsl/span> // IWYU pragma: export
-#include <limits>
 
 namespace o2::framework
 {
@@ -53,6 +52,12 @@ void dereferenceWithWrongType(const char* getter, const char* target);
 void missingFilterDeclaration(int hash, int ai);
 void notBoundTable(const char* tableName);
 void* extractCCDBPayload(char* payload, size_t size, TClass const* cl, const char* what);
+
+template <typename... C>
+auto createFieldsFromColumns(framework::pack<C...>)
+{
+  return std::vector<std::shared_ptr<arrow::Field>>{C::asArrowField()...};
+}
 } // namespace o2::soa
 
 namespace o2::soa
@@ -248,6 +253,11 @@ struct TableMetadata {
       return -1;
     }
   }
+
+  static std::shared_ptr<arrow::Schema> getSchema()
+  {
+    return std::make_shared<arrow::Schema>([]<typename... C>(framework::pack<C...>&& p){ return o2::soa::createFieldsFromColumns(p); }(columns{}));
+  }
 };
 
 template <typename D>
@@ -406,12 +416,6 @@ struct Binding {
   }
 };
 
-template <typename... C>
-auto createFieldsFromColumns(framework::pack<C...>)
-{
-  return std::vector<std::shared_ptr<arrow::Field>>{C::asArrowField()...};
-}
-
 using SelectionVector = std::vector<int64_t>;
 
 template <typename T>

Framework/Core/src/AODReaderHelpers.cxx

@@ -143,13 +143,14 @@ struct Maker {
   std::vector<std::string> labels;
   std::vector<std::shared_ptr<gandiva::Expression>> expressions;
   std::shared_ptr<gandiva::Projector> projector = nullptr;
-  std::shared_ptr<arrow::Schema> schema;
+  std::shared_ptr<arrow::Schema> schema = nullptr;
+  std::shared_ptr<arrow::Schema> inputSchema = nullptr;
 
   header::DataOrigin origin;
   header::DataDescription description;
   header::DataHeader::SubSpecificationType version;
 
-  std::shared_ptr<arrow::Table> make(ProcessingContext& pc)
+  std::shared_ptr<arrow::Table> make(ProcessingContext& pc) const
   {
     std::vector<std::shared_ptr<arrow::Table>> originals;
     for (auto const& label : labels) {
@@ -159,15 +160,6 @@ struct Maker {
     if (fullTable->num_rows() == 0) {
       return arrow::Table::MakeEmpty(schema).ValueOrDie();
     }
-    if (projector == nullptr) {
-      auto s = gandiva::Projector::Make(
-        fullTable->schema(),
-        expressions,
-        &projector);
-      if (!s.ok()) {
-        throw o2::framework::runtime_error_f("Failed to create projector: %s", s.ToString().c_str());
-      }
-    }
 
     return spawnerHelper(fullTable, schema, binding.c_str(), schema->num_fields(), projector);
   }
@@ -201,23 +193,18 @@ struct Spawnable {
     iws.str(loc->defaultValue.get<std::string>());
     outputSchema = ArrowJSONHelpers::read(iws);
 
+    std::vector<std::shared_ptr<arrow::Schema>> schemas;
     for (auto& i : spec.metadata) {
       if (i.name.starts_with("input:")) {
         labels.emplace_back(i.name.substr(6));
+        iws.clear();
+        iws.str(i.defaultValue.get<std::string>());
+        schemas.emplace_back(ArrowJSONHelpers::read(iws));
       }
     }
-
     std::vector<std::shared_ptr<arrow::Field>> fields;
-    for (auto& p : projectors) {
-      expressions::walk(p.node.get(),
-                        [&fields](expressions::Node* n) mutable {
-                          if (n->self.index() == 1) {
-                            auto& b = std::get<expressions::BindingNode>(n->self);
-                            if (std::find_if(fields.begin(), fields.end(), [&b](std::shared_ptr<arrow::Field> const& field) { return field->name() == b.name; }) == fields.end()) {
-                              fields.emplace_back(std::make_shared<arrow::Field>(b.name, expressions::concreteArrowType(b.type)));
-                            }
-                          }
-                        });
+    for (auto& s : schemas) {
+      std::copy(s->fields().begin(), s->fields().end(), std::back_inserter(fields));
     }
     inputSchema = std::make_shared<arrow::Schema>(fields);
 
@@ -233,19 +220,28 @@ struct Spawnable {
     }
   }
 
-  std::shared_ptr<gandiva::Projector> makeProjector()
+  std::shared_ptr<gandiva::Projector> makeProjector() const
   {
-    return expressions::createProjectorHelper(projectors.size(), projectors.data(), inputSchema, outputSchema->fields());
+    std::shared_ptr<gandiva::Projector> p = nullptr;
+    auto s = gandiva::Projector::Make(
+      inputSchema,
+      expressions,
+      &p);
+    if (!s.ok()) {
+      throw o2::framework::runtime_error_f("Failed to create projector: %s", s.ToString().c_str());
+    }
+    return p;
   }
 
-  Maker createMaker()
+  Maker createMaker() const
   {
     return {
       binding,
       labels,
       expressions,
-      nullptr,
+      makeProjector(),
       outputSchema,
+      inputSchema,
       origin,
       description,
       version};