Merge pull request #454 from JuliaOpt/od/fix-bridge

Fix bug in bridges querying index via string

Author: blegat

src/Bridges/bridgeoptimizer.jl

@@ -27,6 +27,8 @@ function isbridged end
 function isbridged(b::AbstractBridgeOptimizer, ::Type{CI{F, S}}) where {F, S}
     return isbridged(b, F, S)
 end
+# We don't bridge variables.
+isbridged(b::AbstractBridgeOptimizer, ::Type{VI}) = false
 
 """
     supportsbridgingconstraint(b::AbstractBridgeOptimizer,
@@ -318,11 +320,36 @@ end
 # Name
 function MOI.canget(b::AbstractBridgeOptimizer, IdxT::Type{<:MOI.Index},
                     name::String)
-    return MOI.canget(b.model, IdxT, name)
+    if isbridged(b, IdxT)
+        return MOI.canget(b.bridged, IdxT, name)
+    else
+        return MOI.canget(b.model, IdxT, name)
+    end
 end
 function MOI.get(b::AbstractBridgeOptimizer, IdxT::Type{<:MOI.Index},
                  name::String)
-    return MOI.get(b.model, IdxT, name)
+    if isbridged(b, IdxT)
+        return MOI.get(b.bridged, IdxT, name)
+    else
+        return MOI.get(b.model, IdxT, name)
+    end
+end
+
+# For the type-unstable case, we have no information as to whether the
+# constraint is in the bridge or the model. Therefore, we try the model first,
+# and then the bridge if that fails. As such, we need canget for either the
+# bridge or the model.
+function MOI.canget(b::AbstractBridgeOptimizer, IdxT::Type{CI},
+                    name::String)
+    return MOI.canget(b.bridged, IdxT, name) || MOI.canget(b.model, IdxT, name)
+end
+function MOI.get(b::AbstractBridgeOptimizer, IdxT::Type{CI},
+                 name::String)
+    if MOI.canget(b.model, IdxT, name)
+        return MOI.get(b.model, IdxT, name)
+    else
+        return MOI.get(b.bridged, IdxT, name)
+    end
 end
 
 # Constraints

test/bridge.jl

@@ -39,6 +39,28 @@ end
     mock = MOIU.MockOptimizer(SimpleModel{Float64}())
     bridgedmock = MOIB.SplitInterval{Float64}(mock)
 
+    @testset "Issue #453" begin
+        MOI.empty!(bridgedmock)
+        MOIU.loadfromstring!(bridgedmock, """
+            variables: x
+            maxobjective: 3.0x
+            c: 2.0x in Interval(1.0, 4.0)
+            d: x in LessThan(1.5)
+        """)
+        x = MOI.get(bridgedmock, MOI.VariableIndex, "x")
+        @test isa(x, MOI.VariableIndex)
+        c1 = MOI.get(bridgedmock, MOI.ConstraintIndex{MOI.ScalarAffineFunction{Float64}, MOI.Interval{Float64}}, "c")
+        @test isa(c1, MOI.ConstraintIndex{MOI.ScalarAffineFunction{Float64}, MOI.Interval{Float64}})
+        c2 = MOI.get(bridgedmock, MOI.ConstraintIndex, "c")
+        @test c1 == c2
+        d1 = MOI.get(bridgedmock, MOI.ConstraintIndex{MOI.SingleVariable, MOI.LessThan{Float64}}, "d")
+        @test isa(d1, MOI.ConstraintIndex{MOI.SingleVariable, MOI.LessThan{Float64}})
+        d2 = MOI.get(bridgedmock, MOI.ConstraintIndex, "d")
+        @test d1 == d2
+    end
+
+    MOI.empty!(bridgedmock)
+
     @testset "Name test" begin
         MOIT.nametest(bridgedmock)
     end