From 8a856bb677fdc1ec1e9a40a8a41e64089f7b6437 Mon Sep 17 00:00:00 2001
From: Oscar Dowson <odow@users.noreply.github.com>
Date: Wed, 16 Aug 2023 12:17:06 +1200
Subject: [PATCH] Add support for constant LHS in complements constraint
 (#3452)

---
 src/complement.jl       | 10 ++++-----
 test/test_complement.jl | 48 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+), 5 deletions(-)

diff --git a/src/complement.jl b/src/complement.jl
index 0f8c782c8c3..e3de1ce2175 100644
--- a/src/complement.jl
+++ b/src/complement.jl
@@ -11,7 +11,7 @@
 
 function _build_complements_constraint(
     errorf::Function,
-    F::AbstractArray{<:AbstractJuMPScalar},
+    F::AbstractArray{<:Union{Real,AbstractJuMPScalar}},
     x::AbstractArray{<:AbstractVariableRef},
 )
     if size(F) != size(x)
@@ -25,7 +25,7 @@ end
 
 function _build_complements_constraint(
     errorf::Function,
-    F::Containers.SparseAxisArray{<:AbstractJuMPScalar},
+    F::Containers.SparseAxisArray{<:Union{Real,AbstractJuMPScalar}},
     x::Containers.SparseAxisArray{<:AbstractVariableRef},
 )
     elements = [F[i] for i in eachindex(F)]
@@ -41,7 +41,7 @@ end
 
 function _build_complements_constraint(
     errorf::Function,
-    ::AbstractArray{<:AbstractJuMPScalar},
+    ::AbstractArray{<:Union{Real,AbstractJuMPScalar}},
     ::AbstractArray{<:AbstractJuMPScalar},
 )
     return errorf("second term must be an array of variables.")
@@ -49,7 +49,7 @@ end
 
 function _build_complements_constraint(
     ::Function,
-    F::AbstractJuMPScalar,
+    F::Union{Real,AbstractJuMPScalar},
     x::AbstractVariableRef,
 )
     return VectorConstraint([F, x], MOI.Complements(2))
@@ -57,7 +57,7 @@ end
 
 function _build_complements_constraint(
     errorf::Function,
-    ::AbstractJuMPScalar,
+    ::Union{Real,AbstractJuMPScalar},
     ::AbstractJuMPScalar,
 )
     return errorf("second term must be a variable.")
diff --git a/test/test_complement.jl b/test/test_complement.jl
index 7c16e4b6fed..725122fb325 100644
--- a/test/test_complement.jl
+++ b/test/test_complement.jl
@@ -57,6 +57,19 @@ function test_scalar_error_F_F()
     return
 end
 
+function test_scalar_error_0_F()
+    model = Model()
+    @variable(model, x >= 0)
+    @test_throws_strip(
+        ErrorException(
+            "In `@constraint(model, 0 ⟂ 2x - 1)`: second term must be a " *
+            "variable.",
+        ),
+        @constraint(model, 0 ⟂ 2x - 1)
+    )
+    return
+end
+
 function test_vector_complements()
     model = Model()
     @variable(model, x[1:2] >= 0)
@@ -116,6 +129,20 @@ function test_vector_error_F_F()
     return
 end
 
+function test_vector_error_0_F()
+    model = Model()
+    @variable(model, x[1:2] >= 0)
+    y = [1.2, -1.3]
+    @test_throws_strip(
+        ErrorException(
+            "In `@constraint(model, y ⟂ 2x .- 1)`: second term must " *
+            "be an array of variables.",
+        ),
+        @constraint(model, y ⟂ 2x .- 1)
+    )
+    return
+end
+
 function test_sparse_complements()
     model = Model()
     @variable(model, x[i = 1:3; isodd(i)] >= 0)
@@ -146,4 +173,25 @@ function test_sparse_key_mismatch()
     return
 end
 
+function test_F_constant_scalar()
+    model = Model()
+    @variable(model, 0 <= x <= 1)
+    @constraint(model, c, 0 ⟂ x)
+    obj = constraint_object(c)
+    @test obj.func == AffExpr[0, x]
+    @test obj.set == MOI.Complements(2)
+    return
+end
+
+function test_F_constant_vector()
+    model = Model()
+    @variable(model, 0 <= x[1:2] <= 1)
+    F = [1.2, -1.3]
+    @constraint(model, c, F ⟂ x)
+    obj = constraint_object(c)
+    @test obj.func == [F; x]
+    @test obj.set == MOI.Complements(4)
+    return
+end
+
 end  # module