fix(SU2_PY): Fix Custom Objective Function for Unsteady Adjoint

SU2_CFD/src/output/CFlowOutput.cpp

@@ -1719,7 +1719,9 @@ void CFlowOutput::AddAerodynamicCoefficients(const CConfig* config) {
 
   /// DESCRIPTION: Angle of attack
   AddHistoryOutput("AOA", "AoA", ScreenOutputFormat::FIXED, "AOA", "Angle of attack");
-
+
+  // CUSTOM_OBJFUNC is added here so historyMap.py knows how to get its value, the actual output is COMBO.
+  if (false) AddHistoryOutput("CUSTOM_OBJFUNC", "ComboObj", ScreenOutputFormat::SCIENTIFIC, "COMBO", "Custom obj. function value.", HistoryFieldType::COEFFICIENT);
   AddHistoryOutput("COMBO", "ComboObj", ScreenOutputFormat::SCIENTIFIC, "COMBO", "Combined obj. function value.", HistoryFieldType::COEFFICIENT);
 }
 

SU2_PY/SU2/io/tools.py

@@ -395,6 +395,13 @@ def read_aerodynamics(
                 )
             Func_Values[key] = value[-1]
 
+    # If only COMBO is present in the history (which is the case when using
+    # CUSTOM_OBJFUNC as objective), expose it also under the logical
+    # name CUSTOM_OBJFUNC so that SU2.eval.functions(function_name="CUSTOM_OBJFUNC")
+    # can retrieve the value without needing a separate history column.
+    if "COMBO" in Func_Values and "CUSTOM_OBJFUNC" not in Func_Values:
+        Func_Values["CUSTOM_OBJFUNC"] = Func_Values["COMBO"]
+
     return Func_Values