Rethrow errors instead of returning FORCED_STOP

ext/NLoptMathOptInterfaceExt.jl

@@ -659,7 +659,7 @@ end
 function fill_gradient!(grad, x, var::MOI.VariableIndex)
     fill!(grad, 0.0)
     grad[var.value] = 1.0
-    return retur
+    return
 end
 
 function fill_gradient!(grad, x, aff::MOI.ScalarAffineFunction{Float64})

src/NLopt.jl

@@ -219,9 +219,9 @@ function chk(o::Opt, result::Result)
         elseif result == FORCED_STOP
             global nlopt_exception
             e = nlopt_exception
+            nlopt_exception = nothing
             if e !== nothing && !isa(e, ForcedStop)
-                nlopt_exception = nothing
-                rethrow(e)
+                throw(e)
             end
         else
             error("nlopt failure $result", _errmsg(o))
@@ -391,8 +391,11 @@ function nlopt_callback_wrapper(n::Cuint, x::Ptr{Cdouble},
                           : unsafe_wrap(Array, grad, (convert(Int, n),))))
         return res::Cdouble
     catch e
-        global nlopt_exception
-        nlopt_exception = e
+        if e isa ForcedStop
+            global nlopt_exception = e
+        else
+            global nlopt_exception = CapturedException(e, catch_backtrace())
+        end
         force_stop!(d.o::Opt)
         return 0.0 # ignored by nlopt
     end
@@ -451,8 +454,11 @@ function nlopt_vcallback_wrapper(m::Cuint, res::Ptr{Cdouble},
             grad == C_NULL ? empty_jac
             : unsafe_wrap(Array, grad, (convert(Int, n),convert(Int, m))))
     catch e
-        global nlopt_exception
-        nlopt_exception = e
+        if e isa ForcedStop
+            global nlopt_exception = e
+        else
+            global nlopt_exception = CapturedException(e, catch_backtrace())
+        end
         force_stop!(d.o::Opt)
     end
     nothing
@@ -621,7 +627,7 @@ function optimize!(o::Opt, x::Vector{Cdouble})
     ret = ccall((:nlopt_optimize,libnlopt), Result, (_Opt, Ptr{Cdouble},
                                                      Ptr{Cdouble}),
                 o, x, opt_f)
-    ret == INVALID_ARGS && chk(o, ret)
+    chk(o, ret)
     return (opt_f[1], x, Symbol(ret))
 end
 

test/runtests.jl

@@ -27,6 +27,38 @@ end
     @test_throws err opt.initial_step
 end
 
+@testset "Fix #156" begin
+    @testset "Test that CapturedException is thrown" begin
+        f(x, g=[]) = (error("test error"); x[1]^2)
+        opt = Opt(:LN_SBPLX, 1)
+        opt.min_objective = f
+        @test_throws CapturedException optimize(opt, [0.1234])
+        @test NLopt.nlopt_exception === nothing
+        try
+            optimize(opt, [0.1234])
+        catch e
+            # Check that the backtrace is being printed
+            @test length(sprint(show, e)) > 100
+        end
+    end
+    @testset "Test that ForcedStop does not rethrow" begin
+        f(x, g=[]) = (throw(NLopt.ForcedStop()); x[1]^2)
+        opt = Opt(:LN_SBPLX, 1)
+        opt.min_objective = f
+        fmin, xmin, ret = optimize(opt, [0.1234])
+        @test ret == :FORCED_STOP
+        @test NLopt.nlopt_exception === nothing
+    end
+    @testset "Test that no error works correctly" begin
+        f(x, g=[]) = (x[1]^2)
+        opt = Opt(:LN_SBPLX, 1)
+        opt.min_objective = f
+        fmin, xmin, ret = optimize(opt, [0.1234])
+        @test ret ∈ (:SUCCESS, :FTOL_REACHED, :XTOL_REACHED)
+        @test NLopt.nlopt_exception === nothing
+    end
+end
+
 @testset "invalid algorithms" begin
     @test_throws ArgumentError("unknown algorithm BILL") Algorithm(:BILL)
     @test_throws ArgumentError("unknown algorithm BILL") Opt(:BILL, 420)