Merge pull request #812 from JuliaRobotics/21Q4/enh/noreturn

don't force return types, esp non-concrete type

Author: dehann

src/CloudGraphsDFG/services/CloudGraphsDFG.jl

@@ -360,7 +360,8 @@ end
 #Alias
 deleteVariable!(dfg::CloudGraphsDFG, variable::DFGVariable) = deleteVariable!(dfg, variable.label)
 
-function deleteFactor!(dfg::CloudGraphsDFG, label::Symbol; suppressGetFactor::Bool=false)::Union{Nothing, DFGFactor}
+# return ::DFGFactor, or workaround ::Nothing, #809
+function deleteFactor!(dfg::CloudGraphsDFG, label::Symbol; suppressGetFactor::Bool=false)
     factor = suppressGetFactor ? nothing : getFactor(dfg, label)
     if factor === nothing && !suppressGetFactor
         error("Unable to retrieve the ID for factor '$label'. Please check your connection to the database and that the factor exists.")
@@ -378,7 +379,7 @@ function deleteFactor!(dfg::CloudGraphsDFG, label::Symbol; suppressGetFactor::Bo
 end
 
 # Alias
-deleteFactor!(dfg::CloudGraphsDFG, factor::DFGFactor; suppressGetFactor::Bool=false)::Union{Nothing, DFGFactor} = deleteFactor!(dfg, factor.label, suppressGetFactor=suppressGetFactor)
+deleteFactor!(dfg::CloudGraphsDFG, factor::DFGFactor; suppressGetFactor::Bool=false) = deleteFactor!(dfg, factor.label, suppressGetFactor=suppressGetFactor)
 
 function getVariables(dfg::CloudGraphsDFG, regexFilter::Union{Nothing, Regex}=nothing; tags::Vector{Symbol}=Symbol[], solvable::Int=0)::Vector{DFGVariable}
     variableIds = listVariables(dfg, regexFilter, tags=tags, solvable=solvable)
@@ -980,4 +981,4 @@ function SkeletonDFG(cfg::CloudGraphsDFG)
     addVariable!.(sfg, _getSkeletonVariables(cfg))
     addFactor!.(sfg, _getSkeletonFactors(cfg))
     return sfg
-end
+end