fix #441

Author: dehann

src/services/AbstractDFG.jl

@@ -54,10 +54,11 @@ getSolverParams(dfg::AbstractDFG) = dfg.solverParams
 
 """
     $(SIGNATURES)
+
+Method must be overloaded by the user for Serialization to work.  E.g. IncrementalInference uses `CommonConvWrapper <: FactorOperationalMemory`.
 """
-getFactorOperationalMemoryType(par::AbstractParams) = par.factorOperationalMemoryType
+getFactorOperationalMemoryType(dummy) = error("Please define this function getFactorOperationalMemoryType for your usecase, e.g. = `IIF.CommonConvWrapper <: FactorOperationalMemory`")
 
-getFactorOperationalMemoryType(dfg::AbstractDFG) = getFactorOperationalMemoryType(getSolverParams(dfg))
 
 ##------------------------------------------------------------------------------
 ## Setters

test/testBlocks.jl

@@ -61,7 +61,8 @@ struct TestCCW{T} <: FactorOperationalMemory where {T<:FunctorInferenceType}
 end
 Base.:(==)(a::TestCCW, b::TestCCW) = a.usrfnc! == b.usrfnc!
 
-DFG.getFactorOperationalMemoryType(par::NoSolverParams) = TestCCW
+# DF, dropping DFG. so that Main context is used and can be overridden by IIF.getFac...Type
+getFactorOperationalMemoryType(par::NoSolverParams) = TestCCW
 
 function Base.convert(::Type{DFG.FunctionNodeData{TestCCW{F}}},
                      d::DFG.PackedFunctionNodeData{<:PackedInferenceType}) where F<:FunctorInferenceType