Implement MOI.default_cache (#130)

Co-authored-by: Benoît Legat <[email protected]>

Project.toml

@@ -9,7 +9,7 @@ MathOptInterface = "b8f27783-ece8-5eb3-8dc8-9495eed66fee"
 
 [compat]
 Clp_jll = "=1.17.6, ~100.1700.600"
-MathOptInterface = "1"
+MathOptInterface = "1.1"
 julia = "1.6"
 
 [extras]

src/MOI_wrapper/MOI_wrapper.jl

@@ -26,6 +26,8 @@ const OptimizerCache = MOI.Utilities.GenericModel{
     },
 }
 
+Base.show(io::IO, ::Type{OptimizerCache}) = print(io, "Clp.OptimizerCache")
+
 const SCALAR_SETS = Union{
     MOI.GreaterThan{Float64},
     MOI.LessThan{Float64},
@@ -72,6 +74,10 @@ mutable struct Optimizer <: MOI.AbstractOptimizer
     end
 end
 
+function MOI.default_cache(::Optimizer, ::Type{Float64})
+    return MOI.Utilities.UniversalFallback(OptimizerCache())
+end
+
 Base.cconvert(::Type{Ptr{Cvoid}}, model::Optimizer) = model
 function Base.unsafe_convert(::Type{Ptr{Cvoid}}, model::Optimizer)
     return model.inner::Ptr{Cvoid}
@@ -335,6 +341,7 @@ function MOI.copy_to(
     dest::Optimizer,
     src::MOI.Utilities.UniversalFallback{OptimizerCache},
 )
+    MOI.Utilities.throw_unsupported(src)
     return MOI.copy_to(dest, src.model)
 end
 

test/MOI_wrapper.jl

@@ -27,12 +27,17 @@ function test_supports_default_copy_to()
 end
 
 function test_runtests()
-    model = MOI.Bridges.full_bridge_optimizer(
-        MOI.Utilities.CachingOptimizer(
-            MOI.Utilities.UniversalFallback(MOI.Utilities.Model{Float64}()),
-            Clp.Optimizer(),
-        ),
-        Float64,
+    # This is what JuMP would construct
+    model = MOI.Utilities.CachingOptimizer(
+        MOI.Utilities.UniversalFallback(MOI.Utilities.Model{Float64}()),
+        MOI.instantiate(Clp.Optimizer; with_bridge_type = Float64),
+    )
+    @test model.optimizer.model.model_cache isa
+          MOI.Utilities.UniversalFallback{Clp.OptimizerCache}
+    # `Variable.ZerosBridge` makes dual needed by some tests fail.
+    MOI.Bridges.remove_bridge(
+        model.optimizer,
+        MathOptInterface.Bridges.Variable.ZerosBridge{Float64},
     )
     MOI.set(model, MOI.Silent(), true)
     MOI.Test.runtests(
@@ -50,10 +55,9 @@ function test_runtests()
 end
 
 function test_Nonexistant_unbounded_ray()
-    model = MOI.Utilities.CachingOptimizer(
-        MOI.Utilities.UniversalFallback(MOI.Utilities.Model{Float64}()),
-        Clp.Optimizer(),
-    )
+    inner = Clp.Optimizer()
+    model =
+        MOI.Utilities.CachingOptimizer(MOI.default_cache(inner, Float64), inner)
     MOI.set(model, MOI.Silent(), true)
     x = MOI.add_variables(model, 5)
     MOI.set(