From ce5c5e056d199aeea534a1e0264a0e3051f8e891 Mon Sep 17 00:00:00 2001
From: odow <o.dowson@gmail.com>
Date: Thu, 18 Nov 2021 17:44:56 +1300
Subject: [PATCH 1/2] Remove source of common test failure in
 LowerBoundAlreadySet

This will decrease coverage for some solvers, but there is a serious
bug in the bridging system that requires a much deeper fix.

This PR removes the common source of failure and adds a broken test to
remind us to fix it in future.
---
 src/Test/test_model.jl                    |  4 ----
 test/Bridges/Constraint/semi_to_binary.jl | 23 +++++++++++++++++++++++
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/src/Test/test_model.jl b/src/Test/test_model.jl
index 520b295035..02110c8032 100644
--- a/src/Test/test_model.jl
+++ b/src/Test/test_model.jl
@@ -804,8 +804,6 @@ function test_model_LowerBoundAlreadySet(
     sets = [
         MOI.EqualTo(lb),
         MOI.Interval(lb, lb),
-        MOI.Semicontinuous(lb, lb),
-        MOI.Semiinteger(lb, lb),
     ]
     set2 = MOI.GreaterThan(lb)
     for set1 in sets
@@ -842,8 +840,6 @@ function test_model_UpperBoundAlreadySet(
     sets = [
         MOI.EqualTo(ub),
         MOI.Interval(ub, ub),
-        MOI.Semicontinuous(ub, ub),
-        MOI.Semiinteger(ub, ub),
     ]
     set2 = MOI.LessThan(ub)
     for set1 in sets
diff --git a/test/Bridges/Constraint/semi_to_binary.jl b/test/Bridges/Constraint/semi_to_binary.jl
index b8811b30dc..09045aaf8d 100644
--- a/test/Bridges/Constraint/semi_to_binary.jl
+++ b/test/Bridges/Constraint/semi_to_binary.jl
@@ -235,6 +235,29 @@ function test_SemiToBinary()
     return
 end
 
+"""
+    test_lower_bound_already_set()
+
+The second call to `add_constraint` is broken because it should throw:
+```julia
+MOI.LowerBoundAlreadySet{
+    MOI.Semicontinuous{Float64},
+    MOI.GreaterThan{Float64},
+}
+```
+See MathOptInterface issue #1431.
+"""
+function test_lower_bound_already_set()
+    model = MOI.Utilities.Model{Float64}()
+    bridged = MOI.Bridges.Constraint.SemiToBinary{Float64}(model)
+    x = MOI.add_variable(bridged)
+    MOI.add_constraint(bridged, x, MOI.Semicontinuous(1.0, 2.0))
+    @test_broken(
+        MOI.add_constraint(bridged, x, MOI.GreaterThan(0.0)) === nothing,
+    )
+    return
+end
+
 end  # module
 
 TestConstraintSemiToBinary.runtests()

From 7c83976c193830a485eb6965388c017f800a62d9 Mon Sep 17 00:00:00 2001
From: Oscar Dowson <odow@users.noreply.github.com>
Date: Fri, 19 Nov 2021 09:30:59 +1300
Subject: [PATCH 2/2] Update test_model.jl

---
 src/Test/test_model.jl | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/src/Test/test_model.jl b/src/Test/test_model.jl
index 02110c8032..e30d5113fc 100644
--- a/src/Test/test_model.jl
+++ b/src/Test/test_model.jl
@@ -801,10 +801,7 @@ function test_model_LowerBoundAlreadySet(
     @requires _supports(config, MOI.delete)
     x = MOI.add_variable(model)
     lb = zero(T)
-    sets = [
-        MOI.EqualTo(lb),
-        MOI.Interval(lb, lb),
-    ]
+    sets = [MOI.EqualTo(lb), MOI.Interval(lb, lb)]
     set2 = MOI.GreaterThan(lb)
     for set1 in sets
         if !MOI.supports_constraint(model, MOI.VariableIndex, typeof(set1))
@@ -837,10 +834,7 @@ function test_model_UpperBoundAlreadySet(
     x = MOI.add_variable(model)
     ub = zero(T)
     @requires MOI.supports_constraint(model, MOI.VariableIndex, MOI.LessThan{T})
-    sets = [
-        MOI.EqualTo(ub),
-        MOI.Interval(ub, ub),
-    ]
+    sets = [MOI.EqualTo(ub), MOI.Interval(ub, ub)]
     set2 = MOI.LessThan(ub)
     for set1 in sets
         if !MOI.supports_constraint(model, MOI.VariableIndex, typeof(set1))