Fix show for problems with variables containing constraints (#649)

Author: odow

src/utilities/show.jl

@@ -217,10 +217,16 @@ function TreePrint.print_tree(io::IO, p::Problem, args...; kwargs...)
         args...;
         kwargs...,
     )
-    if !isempty(p.constraints)
+    all_constraints = copy(p.constraints)
+    for leaf in AbstractTrees.Leaves(p)
+        if leaf isa AbstractVariable
+            append!(all_constraints, get_constraints(leaf))
+        end
+    end
+    if !isempty(all_constraints)
         TreePrint.print_tree(
             io,
-            ProblemConstraintsRoot(p.constraints),
+            ProblemConstraintsRoot(all_constraints),
             args...;
             kwargs...,
         )

test/test_utilities.jl

@@ -1325,6 +1325,16 @@ function test_Constant_complex()
     return
 end
 
+function test_show_with_variable_constraints()
+    x = Variable()
+    add_constraint!(x, x >= 1)
+    p = minimize(x)
+    tree = sprint(show, p)
+    @test occursin("subject to", tree)
+    @test occursin("≥ constraint (affine)", tree)
+    return
+end
+
 end  # TestUtilities
 
 TestUtilities.runtests()