[Utilities] Drop MOI.RawParameters when resetting a CachingOptimizer

src/Utilities/cachingoptimizer.jl

@@ -113,14 +113,28 @@ mode(m::CachingOptimizer) = m.mode
 """
     reset_optimizer(m::CachingOptimizer, optimizer::MOI.AbstractOptimizer)
 
-Sets or resets `m` to have the given empty optimizer. Can be called
-from any state. The `CachingOptimizer` will be in state `EMPTY_OPTIMIZER` after the call.
+Sets or resets `m` to have the given empty optimizer `optimizer`.
+
+Can be called from any state. An assertion error will be thrown if `optimizer`
+is not empty.
+
+The `CachingOptimizer` `m` will be in state `EMPTY_OPTIMIZER` after the call.
 """
 function reset_optimizer(m::CachingOptimizer, optimizer::MOI.AbstractOptimizer)
     @assert MOI.is_empty(optimizer)
     m.optimizer = optimizer
     m.state = EMPTY_OPTIMIZER
     for attr in MOI.get(m.model_cache, MOI.ListOfOptimizerAttributesSet())
+        # Skip attributes which don't apply to the new optimizer.
+        if attr isa MOI.RawParameter
+            # Even if the optimizer claims to `supports` `attr`, the value 
+            # might have a different meaning (e.g., two solvers with `logLevel`
+            # as a RawParameter). To be on the safe side, just skip all raw 
+            # parameters.
+            continue
+        elseif !MOI.is_copyable(attr) || !MOI.supports(m.optimizer, attr)
+            continue
+        end
         value = MOI.get(m.model_cache, attr)
         optimizer_value = map_indices(m.model_to_optimizer_map, value)
         MOI.set(m.optimizer, attr, optimizer_value)

test/Utilities/cachingoptimizer.jl

@@ -652,3 +652,31 @@ end
     MOIU.reset_optimizer(model, optimizer)
     constrained_variables_test(model)
 end
+
+struct Issue1220 <: MOI.AbstractOptimizer
+    optimizer_attributes::Dict{Any,Any}
+    Issue1220() = new(Dict{Any,Any}())
+end
+MOI.is_empty(model::Issue1220) = isempty(model.optimizer_attributes)
+function MOI.get(model::Issue1220, ::MOI.ListOfOptimizerAttributesSet)
+    return collect(keys(model.optimizer_attributes))
+end
+MOI.supports(::Issue1220, ::MOI.AbstractOptimizerAttribute) = true
+MOI.supports(::Issue1220, ::MOI.NumberOfThreads) = false
+function MOI.get(model::Issue1220, attr::MOI.AbstractOptimizerAttribute)
+    return model.optimizer_attributes[attr]
+end
+function MOI.set(model::Issue1220, attr::MOI.AbstractOptimizerAttribute, value)
+    model.optimizer_attributes[attr] = value
+    return value
+end
+@testset "Issue1220_dont_pass_raw_parameter" begin
+    model = MOIU.CachingOptimizer(Issue1220(), Issue1220())
+    MOI.set(model, MOI.Silent(), true)
+    MOI.set(model, MOI.RawParameter("foo"), "bar")
+    MOI.set(model, MOI.NumberOfThreads(), 1)
+    MOIU.reset_optimizer(model, Issue1220())
+    @test MOI.get(model, MOI.Silent()) == true
+    @test_throws KeyError MOI.get(model, MOI.RawParameter("foo"))
+    @test_throws KeyError MOI.get(model, MOI.NumberOfThreads())
+end