✨ Add RequiredBridges attribute

Author: blegat

src/Bridges/lazybridgeoptimizer.jl

@@ -19,12 +19,14 @@ struct LazyBridgeOptimizer{OT<:MOI.ModelLike, MT<:MOI.ModelLike} <: AbstractBrid
     best::Dict{Tuple{DataType, DataType}, DataType} # (F, S) -> Bridge to be used for an `F`-in-`S` constraint
 end
 function LazyBridgeOptimizer(model::MOI.ModelLike, bridged::MOI.ModelLike)
-    LazyBridgeOptimizer{typeof(model),
-                             typeof(bridged)}(model, bridged,
-                                              Dict{CI, AbstractBridge}(),
-                                              Any[],
-                                              Dict{Tuple{DataType, DataType}, Int}(),
-                                              Dict{Tuple{DataType, DataType}, DataType}())
+    optimizer = LazyBridgeOptimizer{typeof(model), typeof(bridged)}(
+        model, bridged, Dict{CI, AbstractBridge}(), Any[],
+        Dict{Tuple{DataType, DataType}, Int}(),
+        Dict{Tuple{DataType, DataType}, DataType}())
+    for bridge in MOI.get(model, MOI.RequiredBridges())
+        add_bridge(model, bridge)
+    end
+    return optimizer
 end
 
 function _dist(b::LazyBridgeOptimizer, F::Type{<:MOI.AbstractFunction}, S::Type{<:MOI.AbstractSet})

src/attributes.jl

@@ -332,6 +332,18 @@ An optimizer attribute for the string identifying the solver/optimizer.
 """
 struct SolverName <: AbstractOptimizerAttribute end
 
+"""
+    RequiredBridges()
+
+A list of bridges that are required when using the optimizer. For instance, if
+an optimizer uses a different representation of a set, it can defined a custom
+set with a bridge that transforms the MOI set into the custom set and return
+this bridge as value of this attribute.
+"""
+struct RequiredBridges <: AbstractOptimizerAttribute end
+
+get(model::ModelLike, ::RequiredBridges) = []
+
 ## Model attributes
 
 """
@@ -900,7 +912,8 @@ method should be defined for attibutes which are copied indirectly during
 * [`ListOfOptimizerAttributesSet`](@ref), [`ListOfModelAttributesSet`](@ref),
   [`ListOfConstraintAttributesSet`](@ref) and
   [`ListOfVariableAttributesSet`](@ref).
-* [`SolverName`](@ref) and [`RawSolver`](@ref): these attributes cannot be set.
+* [`SolverName`](@ref), [`RequiredBridges`](@ref) and [`RawSolver`](@ref): these
+  attributes cannot be set.
 * [`NumberOfVariables`](@ref) and [`ListOfVariableIndices`](@ref): these
   attributes are set indirectly by [`add_variable`](@ref) and
   [`add_variables`](@ref).
@@ -919,6 +932,7 @@ function is_copyable(::Union{ListOfOptimizerAttributesSet,
                              ListOfConstraintAttributesSet,
                              ListOfVariableAttributesSet,
                              SolverName,
+                             RequiredBridges,
                              RawSolver,
                              NumberOfVariables,
                              ListOfVariableIndices,