From a6596d2780afe55e28b2b83105014b261d15d618 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Fri, 15 Dec 2023 00:03:00 +0100
Subject: [PATCH 01/22] [Bridges] Fix ConstraintIndex conflicts between
 variable and constraint bridges

---
 src/Bridges/Constraint/map.jl   | 16 ++++++++++++++++
 src/Bridges/Variable/map.jl     | 22 +++++++++++++++++-----
 src/Bridges/bridge_optimizer.jl |  2 ++
 3 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/src/Bridges/Constraint/map.jl b/src/Bridges/Constraint/map.jl
index 38cfbb11d7..c78376df7f 100644
--- a/src/Bridges/Constraint/map.jl
+++ b/src/Bridges/Constraint/map.jl
@@ -280,13 +280,29 @@ Return a new constraint index `ci` and store the mapping `ci => bridge`.
 """
 function add_key_for_bridge end
 
+_ensure_available(::Map, ::Type, ::Type, ::Function) = nothing
+function _ensure_available(
+    map::Map,
+    F::Type{MOI.VectorOfVariables},
+    ::Type{S},
+    is_available::Function,
+) where {S}
+    while !is_available(MOI.ConstraintIndex{F,S}(length(map.bridges) + 1))
+        push!(map.bridges, nothing)
+        push!(map.constraint_types, (F, S))
+    end
+    return
+end
+
 function add_key_for_bridge(
     map::Map,
     bridge::AbstractBridge,
     ::F,
     ::S,
+    is_available::Function,
 ) where {F<:MOI.AbstractFunction,S<:MOI.AbstractSet}
     _register_for_final_touch(map, bridge)
+    _ensure_available(map, F, S, is_available)
     push!(map.bridges, bridge)
     push!(map.constraint_types, (F, S))
     return _index(length(map.bridges), F, S)
diff --git a/src/Bridges/Variable/map.jl b/src/Bridges/Variable/map.jl
index 7b9e98adb0..26782c88c4 100644
--- a/src/Bridges/Variable/map.jl
+++ b/src/Bridges/Variable/map.jl
@@ -36,6 +36,10 @@ mutable struct Map <: AbstractDict{MOI.VariableIndex,AbstractBridge}
     current_context::Int64
     # Context of constraint bridged by constraint bridges
     constraint_context::Dict{MOI.ConstraintIndex,Int64}
+    # `(ci::ConstraintIndex{MOI.VectorOfVariables}).value` ->
+    # the first variable index
+    # and `0` if it is the index of a constraint bridge
+    vector_of_variables_map::Vector{Int64}
 end
 
 function Map()
@@ -48,6 +52,7 @@ function Map()
         Int64[],
         0,
         Dict{MOI.ConstraintIndex,Int64}(),
+        Int64[],
     )
 end
 
@@ -76,6 +81,7 @@ function Base.empty!(map::Map)
     empty!(map.parent_index)
     map.current_context = 0
     empty!(map.constraint_context)
+    empty!(map.vector_of_variables_map)
     return map
 end
 
@@ -350,6 +356,7 @@ function add_keys_for_bridge(
     map::Map,
     bridge_fun::Function,
     set::MOI.AbstractVectorSet,
+    is_available::Function,
 )
     if iszero(MOI.dimension(set))
         return MOI.VariableIndex[],
@@ -386,9 +393,13 @@ function add_keys_for_bridge(
             end
         end
     end
-    index = first(variables).value
-    return variables,
-    MOI.ConstraintIndex{MOI.VectorOfVariables,typeof(set)}(index)
+    F = MOI.VectorOfVariables
+    S = typeof(set)
+    while !is_available(MOI.ConstraintIndex{F,S}(-length(map.vector_of_variables_map) - 1))
+        push!(map.vector_of_variables_map, 0)
+    end
+    push!(map.vector_of_variables_map, first(variables).value)
+    return variables, MOI.ConstraintIndex{F,S}(-length(map.vector_of_variables_map))
 end
 
 """
@@ -408,12 +419,13 @@ Return `MOI.VectorOfVariables(vis)` where `vis` is the vector of bridged
 variables corresponding to `ci`.
 """
 function function_for(map::Map, ci::MOI.ConstraintIndex{MOI.VectorOfVariables})
+    index = map.vector_of_variables_map[ci]
     variables = MOI.VariableIndex[]
-    for i in ci.value:-1:-length(map.bridges)
+    for i in index:-1:-length(map.bridges)
         vi = MOI.VariableIndex(i)
         if map.index_in_vector[-vi.value] == -1
             continue
-        elseif bridge_index(map, vi) == -ci.value
+        elseif bridge_index(map, vi) == -index
             push!(variables, vi)
         else
             break
diff --git a/src/Bridges/bridge_optimizer.jl b/src/Bridges/bridge_optimizer.jl
index e0100e6344..34b7ddd666 100644
--- a/src/Bridges/bridge_optimizer.jl
+++ b/src/Bridges/bridge_optimizer.jl
@@ -1721,6 +1721,7 @@ function add_bridged_constraint(b, BridgeType, f, s)
         bridge,
         f,
         s,
+        Base.Fix1(haskey, Variable.bridges(b)),
     )
     Variable.register_context(Variable.bridges(b), ci)
     return ci
@@ -2000,6 +2001,7 @@ function MOI.add_constrained_variables(
             Variable.bridges(b)::Variable.Map,
             () -> Variable.bridge_constrained_variable(BridgeType, b, set),
             set,
+            Base.Fix1(haskey, Constraint.bridges(b)),
         )
     else
         variables = MOI.add_variables(b, MOI.dimension(set))

From 378f811437238a330e748d3b689705fd5d30da76 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Sat, 16 Dec 2023 12:12:18 +0100
Subject: [PATCH 02/22] Fixes

---
 src/Bridges/Variable/map.jl     | 7 +++++--
 src/Bridges/bridge_optimizer.jl | 4 ++--
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/src/Bridges/Variable/map.jl b/src/Bridges/Variable/map.jl
index 26782c88c4..4023807cf8 100644
--- a/src/Bridges/Variable/map.jl
+++ b/src/Bridges/Variable/map.jl
@@ -395,11 +395,14 @@ function add_keys_for_bridge(
     end
     F = MOI.VectorOfVariables
     S = typeof(set)
-    while !is_available(MOI.ConstraintIndex{F,S}(-length(map.vector_of_variables_map) - 1))
+    while !is_available(
+        MOI.ConstraintIndex{F,S}(-length(map.vector_of_variables_map) - 1),
+    )
         push!(map.vector_of_variables_map, 0)
     end
     push!(map.vector_of_variables_map, first(variables).value)
-    return variables, MOI.ConstraintIndex{F,S}(-length(map.vector_of_variables_map))
+    return variables,
+    MOI.ConstraintIndex{F,S}(-length(map.vector_of_variables_map))
 end
 
 """
diff --git a/src/Bridges/bridge_optimizer.jl b/src/Bridges/bridge_optimizer.jl
index 34b7ddd666..e7b9448da8 100644
--- a/src/Bridges/bridge_optimizer.jl
+++ b/src/Bridges/bridge_optimizer.jl
@@ -1721,7 +1721,7 @@ function add_bridged_constraint(b, BridgeType, f, s)
         bridge,
         f,
         s,
-        Base.Fix1(haskey, Variable.bridges(b)),
+        !Base.Fix1(haskey, Variable.bridges(b)),
     )
     Variable.register_context(Variable.bridges(b), ci)
     return ci
@@ -2001,7 +2001,7 @@ function MOI.add_constrained_variables(
             Variable.bridges(b)::Variable.Map,
             () -> Variable.bridge_constrained_variable(BridgeType, b, set),
             set,
-            Base.Fix1(haskey, Constraint.bridges(b)),
+            !Base.Fix1(haskey, Constraint.bridges(b)),
         )
     else
         variables = MOI.add_variables(b, MOI.dimension(set))

From 011b80bd40a7b5250c9c7d7dcd047062b0d8f41d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Sat, 16 Dec 2023 18:42:21 +0100
Subject: [PATCH 03/22] Fix

---
 src/Bridges/Constraint/map.jl | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/Bridges/Constraint/map.jl b/src/Bridges/Constraint/map.jl
index c78376df7f..8ba3152d44 100644
--- a/src/Bridges/Constraint/map.jl
+++ b/src/Bridges/Constraint/map.jl
@@ -274,6 +274,7 @@ end
         bridge::AbstractBridge,
         func::MOI.AbstractFunction,
         set::MOI.AbstractSet,
+        is_available::Function,
     )
 
 Return a new constraint index `ci` and store the mapping `ci => bridge`.
@@ -313,6 +314,7 @@ function add_key_for_bridge(
     bridge::AbstractBridge,
     func::MOI.VariableIndex,
     ::S,
+    ::Function,
 ) where {S<:MOI.AbstractScalarSet}
     _register_for_final_touch(map, bridge)
     map.single_variable_constraints[(func.value, S)] = bridge

From 7466479926495996c72cdcbe882fd0b37488c493 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Sat, 16 Dec 2023 21:22:44 +0100
Subject: [PATCH 04/22] Fixes

---
 src/Bridges/Variable/map.jl    | 44 ++++++++++++++++++++++------------
 test/Bridges/Constraint/map.jl | 10 +++++++-
 test/Bridges/Variable/map.jl   | 17 ++++++++++---
 3 files changed, 52 insertions(+), 19 deletions(-)

diff --git a/src/Bridges/Variable/map.jl b/src/Bridges/Variable/map.jl
index 4023807cf8..330a269fed 100644
--- a/src/Bridges/Variable/map.jl
+++ b/src/Bridges/Variable/map.jl
@@ -40,6 +40,9 @@ mutable struct Map <: AbstractDict{MOI.VariableIndex,AbstractBridge}
     # the first variable index
     # and `0` if it is the index of a constraint bridge
     vector_of_variables_map::Vector{Int64}
+    # `(ci::ConstraintIndex{MOI.VectorOfVariables}).value` ->
+    # the dimension of the set
+    vector_of_variables_length::Vector{Int64}
 end
 
 function Map()
@@ -53,6 +56,7 @@ function Map()
         0,
         Dict{MOI.ConstraintIndex,Int64}(),
         Int64[],
+        Int64[],
     )
 end
 
@@ -82,6 +86,7 @@ function Base.empty!(map::Map)
     map.current_context = 0
     empty!(map.constraint_context)
     empty!(map.vector_of_variables_map)
+    empty!(map.vector_of_variables_length)
     return map
 end
 
@@ -114,7 +119,7 @@ function Base.delete!(map::Map, vi::MOI.VariableIndex)
         delete!(map, [vi])
     else
         # Delete variable in vector and resize vector
-        map.info[bridge_index(map, vi)] += 1
+        map.vector_of_variables_length[-map.info[bridge_index(map, vi)]] -= 1
         for i in (-vi.value):length(map.index_in_vector)
             if map.index_in_vector[i] == -1
                 continue
@@ -213,10 +218,17 @@ function number_with_set(map::Map, S::Type{<:MOI.AbstractSet})
     return count(isequal(S), map.sets)
 end
 
+_constraint
+
 function constraint(map::Map, vi::MOI.VariableIndex)
     S = constrained_set(map, vi)::Type{<:MOI.AbstractSet}
     F = MOI.Utilities.variable_function_type(S)
-    return MOI.ConstraintIndex{F,S}(-bridge_index(map, vi))
+    index = bridge_index(map, vi)
+    constraint_index = map.info[index]
+    if iszero(constraint_index)
+        constraint_index = -index
+    end
+    return MOI.ConstraintIndex{F,S}(constraint_index)
 end
 
 """
@@ -226,8 +238,8 @@ Return the list of constraints corresponding to bridged variables in `S`.
 """
 function constraints_with_set(map::Map, S::Type{<:MOI.AbstractSet})
     F = MOI.Utilities.variable_function_type(S)
-    return [
-        MOI.ConstraintIndex{F,S}(-i) for
+    return MOI.ConstraintIndex{F,S}[
+        constraint(map, MOI.VariableIndex(-i)) for
         i in eachindex(map.sets) if map.sets[i] == S
     ]
 end
@@ -278,7 +290,7 @@ If `vi` was bridged in a scalar set, it returns 0. Otherwise, it
 returns the dimension of the set.
 """
 function length_of_vector_of_variables(map::Map, vi::MOI.VariableIndex)
-    return -map.info[bridge_index(map, vi)]
+    return map.vector_of_variables_length[-map.info[bridge_index(map, vi)]]
 end
 
 """
@@ -364,7 +376,17 @@ function add_keys_for_bridge(
     end
     push!(map.parent_index, map.current_context)
     bridge_index = Int64(length(map.parent_index))
-    push!(map.info, -MOI.dimension(set))
+    F = MOI.VectorOfVariables
+    S = typeof(set)
+    while !is_available(
+        MOI.ConstraintIndex{F,S}(-length(map.vector_of_variables_map) - 1),
+    )
+        push!(map.vector_of_variables_map, 0)
+        push!(map.vector_of_variables_length, 0)
+    end
+    push!(map.vector_of_variables_map, -bridge_index)
+    push!(map.vector_of_variables_length, MOI.dimension(set))
+    push!(map.info, -length(map.vector_of_variables_length))
     push!(map.index_in_vector, 1)
     push!(map.bridges, nothing)
     push!(map.sets, typeof(set))
@@ -393,14 +415,6 @@ function add_keys_for_bridge(
             end
         end
     end
-    F = MOI.VectorOfVariables
-    S = typeof(set)
-    while !is_available(
-        MOI.ConstraintIndex{F,S}(-length(map.vector_of_variables_map) - 1),
-    )
-        push!(map.vector_of_variables_map, 0)
-    end
-    push!(map.vector_of_variables_map, first(variables).value)
     return variables,
     MOI.ConstraintIndex{F,S}(-length(map.vector_of_variables_map))
 end
@@ -422,7 +436,7 @@ Return `MOI.VectorOfVariables(vis)` where `vis` is the vector of bridged
 variables corresponding to `ci`.
 """
 function function_for(map::Map, ci::MOI.ConstraintIndex{MOI.VectorOfVariables})
-    index = map.vector_of_variables_map[ci]
+    index = map.vector_of_variables_map[-ci.value]
     variables = MOI.VariableIndex[]
     for i in index:-1:-length(map.bridges)
         vi = MOI.VariableIndex(i)
diff --git a/test/Bridges/Constraint/map.jl b/test/Bridges/Constraint/map.jl
index 3671259c47..26df06122b 100644
--- a/test/Bridges/Constraint/map.jl
+++ b/test/Bridges/Constraint/map.jl
@@ -34,7 +34,13 @@ function test_map()
     x = MOI.VariableIndex(1)
     y = MOI.VariableIndex(2)
     b1 = ConstraintDummyBridge(1)
-    c1 = MOI.Bridges.Constraint.add_key_for_bridge(map, b1, x, MOI.EqualTo(0.0))
+    c1 = MOI.Bridges.Constraint.add_key_for_bridge(
+        map,
+        b1,
+        x,
+        MOI.EqualTo(0.0),
+        ci -> true,
+    )
 
     @test c1.value == x.value
     @test haskey(map, c1)
@@ -53,6 +59,7 @@ function test_map()
         b2,
         vov,
         MOI.SecondOrderCone(2),
+        ci -> true,
     )
     @test c2.value == -1
     @test haskey(map, c2)
@@ -70,6 +77,7 @@ function test_map()
         b3,
         1.0x + 2.0,
         MOI.EqualTo(0.0),
+        ci -> true,
     )
     @test haskey(map, c3)
     @test map[c3] == b3
diff --git a/test/Bridges/Variable/map.jl b/test/Bridges/Variable/map.jl
index be2d67f848..a2c664f602 100644
--- a/test/Bridges/Variable/map.jl
+++ b/test/Bridges/Variable/map.jl
@@ -82,8 +82,14 @@ function test_map()
     set2 = MOI.Zeros(4)
     F2 = MOI.VectorOfVariables
     S2 = typeof(set2)
-    v2, c2 = MOI.Bridges.Variable.add_keys_for_bridge(map, () -> b2, set2)
-    @test v2[1].value == c2.value == -2
+    v2, c2 = MOI.Bridges.Variable.add_keys_for_bridge(
+        map,
+        () -> b2,
+        set2,
+        ci -> true,
+    )
+    @test v2[1].value == -2
+    @test c2.value == -1
     @test MOI.Bridges.Variable.has_keys(map, v2)
     @test !MOI.Bridges.Variable.has_keys(map, v2[4:-1:1])
     for i in 1:4
@@ -117,7 +123,12 @@ function test_map()
 
     b3 = VariableDummyBridge(3)
     set3 = MOI.Zeros(0)
-    v3, c3 = MOI.Bridges.Variable.add_keys_for_bridge(map, () -> b3, set3)
+    v3, c3 = MOI.Bridges.Variable.add_keys_for_bridge(
+        map,
+        () -> b3,
+        set3,
+        ci -> true,
+    )
 
     @test isempty(v3)
     @test c3.value == 0

From 84a0d9ba6a36c15a7bbc360a153c22a71195dfae Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Sun, 17 Dec 2023 19:08:02 +0100
Subject: [PATCH 05/22] Fix

---
 src/Bridges/Variable/map.jl | 2 --
 1 file changed, 2 deletions(-)

diff --git a/src/Bridges/Variable/map.jl b/src/Bridges/Variable/map.jl
index 330a269fed..09e1138c83 100644
--- a/src/Bridges/Variable/map.jl
+++ b/src/Bridges/Variable/map.jl
@@ -218,8 +218,6 @@ function number_with_set(map::Map, S::Type{<:MOI.AbstractSet})
     return count(isequal(S), map.sets)
 end
 
-_constraint
-
 function constraint(map::Map, vi::MOI.VariableIndex)
     S = constrained_set(map, vi)::Type{<:MOI.AbstractSet}
     F = MOI.Utilities.variable_function_type(S)

From 9a9c0df3501bfafee6f4ad48d2fff2193d492457 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Sun, 17 Dec 2023 22:22:35 +0100
Subject: [PATCH 06/22] Fixes

---
 src/Bridges/Variable/map.jl  | 7 ++++++-
 test/Bridges/Variable/map.jl | 1 +
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/Bridges/Variable/map.jl b/src/Bridges/Variable/map.jl
index 09e1138c83..4ac41f2b26 100644
--- a/src/Bridges/Variable/map.jl
+++ b/src/Bridges/Variable/map.jl
@@ -288,7 +288,12 @@ If `vi` was bridged in a scalar set, it returns 0. Otherwise, it
 returns the dimension of the set.
 """
 function length_of_vector_of_variables(map::Map, vi::MOI.VariableIndex)
-    return map.vector_of_variables_length[-map.info[bridge_index(map, vi)]]
+    info = map.info[bridge_index(map, vi)]
+    if iszero(info)
+        return 0
+    else
+        return map.vector_of_variables_length[-info]
+    end
 end
 
 """
diff --git a/test/Bridges/Variable/map.jl b/test/Bridges/Variable/map.jl
index a2c664f602..d02c689ebd 100644
--- a/test/Bridges/Variable/map.jl
+++ b/test/Bridges/Variable/map.jl
@@ -59,6 +59,7 @@ function test_map()
     )
     @test v1.value == c1.value == -1
     @test MOI.Bridges.Variable.constraint(map, v1) == c1
+    @test MOI.Bridges.Variable.length_of_vector_of_variables(map, v1) == 0
     @test haskey(map, v1)
     @test map[v1] == b1
     @test MOI.Bridges.Variable.constrained_set(map, v1) == S1

From 1c84c46a7f821f009463cc4721bd2118ec1de871 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Sun, 17 Dec 2023 23:13:56 +0100
Subject: [PATCH 07/22] Fixes

---
 src/Bridges/Variable/map.jl           | 14 ++++++++++++++
 src/Bridges/bridge_optimizer.jl       |  2 +-
 test/Bridges/Variable/map.jl          |  2 ++
 test/Bridges/lazy_bridge_optimizer.jl | 16 ++++++++++++++++
 4 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/src/Bridges/Variable/map.jl b/src/Bridges/Variable/map.jl
index 4ac41f2b26..db95915554 100644
--- a/src/Bridges/Variable/map.jl
+++ b/src/Bridges/Variable/map.jl
@@ -229,6 +229,20 @@ function constraint(map::Map, vi::MOI.VariableIndex)
     return MOI.ConstraintIndex{F,S}(constraint_index)
 end
 
+function MOI.is_valid(map::Map, ci::MOI.ConstraintIndex{MOI.VectorOfVariables,S}) where {S}
+    if !(-ci.value in eachindex(map.vector_of_variables_map))
+        return false
+    end
+    index = -map.vector_of_variables_map[-ci.value]
+    return index in eachindex(map.bridges) && !isnothing(map.bridges[index]) && map.sets[index] === S
+end
+
+function MOI.is_valid(map::Map, ci::MOI.ConstraintIndex{MOI.VariableIndex,S}) where {S}
+    index = -ci.value
+    return index in eachindex(map.bridges) && !isnothing(map.bridges[index]) && map.sets[index] === S
+end
+
+
 """
     constraints_with_set(map::Map, S::Type{<:MOI.AbstractSet})
 
diff --git a/src/Bridges/bridge_optimizer.jl b/src/Bridges/bridge_optimizer.jl
index e7b9448da8..1ef369b881 100644
--- a/src/Bridges/bridge_optimizer.jl
+++ b/src/Bridges/bridge_optimizer.jl
@@ -1721,7 +1721,7 @@ function add_bridged_constraint(b, BridgeType, f, s)
         bridge,
         f,
         s,
-        !Base.Fix1(haskey, Variable.bridges(b)),
+        !Base.Fix1(MOI.is_valid, Variable.bridges(b)),
     )
     Variable.register_context(Variable.bridges(b), ci)
     return ci
diff --git a/test/Bridges/Variable/map.jl b/test/Bridges/Variable/map.jl
index d02c689ebd..a2a7064cde 100644
--- a/test/Bridges/Variable/map.jl
+++ b/test/Bridges/Variable/map.jl
@@ -53,6 +53,7 @@ function test_map()
     F1 = MOI.VariableIndex
     S1 = typeof(set1)
     v1, c1 = MOI.Bridges.Variable.add_key_for_bridge(map, () -> b1, set1)
+    MOI.is_valid(map, c1)
     cannot_unbridge_err = ErrorException(
         "Cannot unbridge function because some variables are bridged by variable" *
         " bridges that do not support reverse mapping, e.g., `ZerosBridge`.",
@@ -89,6 +90,7 @@ function test_map()
         set2,
         ci -> true,
     )
+    MOI.is_valid(map, c2)
     @test v2[1].value == -2
     @test c2.value == -1
     @test MOI.Bridges.Variable.has_keys(map, v2)
diff --git a/test/Bridges/lazy_bridge_optimizer.jl b/test/Bridges/lazy_bridge_optimizer.jl
index 8c27bd80f9..57ce1f38c3 100644
--- a/test/Bridges/lazy_bridge_optimizer.jl
+++ b/test/Bridges/lazy_bridge_optimizer.jl
@@ -332,6 +332,22 @@ function test_MOI_runtests_GeometricSDPAModel()
     return
 end
 
+function test_index_conflict()
+    optimizer = StandardSDPAModel{Float64}()
+    model = MOI.Bridges.full_bridge_optimizer(optimizer, Float64)
+    x, cx = MOI.add_constrained_variables(model, MOI.Nonpositives(1))
+    @test MOI.is_valid(model, x[1])
+    @test MOI.is_valid(model, cx)
+    y, cy = MOI.add_constrained_variables(model, MOI.Nonpositives(1))
+    @test MOI.is_valid(model, y[1])
+    @test MOI.is_valid(model, cy)
+    c = MOI.add_constraint(model, MOI.VectorOfVariables(y), MOI.Nonpositives(1))
+    MOI.is_valid(model, c)
+    b1 = MOI.Bridges.bridge(model, c)
+    b2 = MOI.Bridges.bridge(model, b1.constraint)
+    @test c != b2.slack_in_set
+end
+
 function test_show_SPDA()
     model = StandardSDPAModel{Float64}()
     model_str = sprint(MOI.Utilities.print_with_acronym, string(typeof(model)))

From be707aa2989990296f1c1055864e352ed9787ae7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Mon, 18 Dec 2023 15:22:02 +0100
Subject: [PATCH 08/22] Fixes

---
 src/Bridges/Constraint/map.jl |  2 +-
 src/Bridges/Variable/map.jl   | 19 ++++++++++++++-----
 2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/src/Bridges/Constraint/map.jl b/src/Bridges/Constraint/map.jl
index 8ba3152d44..c2bd084868 100644
--- a/src/Bridges/Constraint/map.jl
+++ b/src/Bridges/Constraint/map.jl
@@ -288,7 +288,7 @@ function _ensure_available(
     ::Type{S},
     is_available::Function,
 ) where {S}
-    while !is_available(MOI.ConstraintIndex{F,S}(length(map.bridges) + 1))
+    while !is_available(MOI.ConstraintIndex{F,S}(-length(map.bridges) - 1))
         push!(map.bridges, nothing)
         push!(map.constraint_types, (F, S))
     end
diff --git a/src/Bridges/Variable/map.jl b/src/Bridges/Variable/map.jl
index db95915554..7c4dd2344e 100644
--- a/src/Bridges/Variable/map.jl
+++ b/src/Bridges/Variable/map.jl
@@ -229,20 +229,29 @@ function constraint(map::Map, vi::MOI.VariableIndex)
     return MOI.ConstraintIndex{F,S}(constraint_index)
 end
 
-function MOI.is_valid(map::Map, ci::MOI.ConstraintIndex{MOI.VectorOfVariables,S}) where {S}
+function MOI.is_valid(
+    map::Map,
+    ci::MOI.ConstraintIndex{MOI.VectorOfVariables,S},
+) where {S}
     if !(-ci.value in eachindex(map.vector_of_variables_map))
         return false
     end
     index = -map.vector_of_variables_map[-ci.value]
-    return index in eachindex(map.bridges) && !isnothing(map.bridges[index]) && map.sets[index] === S
+    return index in eachindex(map.bridges) &&
+           !isnothing(map.bridges[index]) &&
+           map.sets[index] === S
 end
 
-function MOI.is_valid(map::Map, ci::MOI.ConstraintIndex{MOI.VariableIndex,S}) where {S}
+function MOI.is_valid(
+    map::Map,
+    ci::MOI.ConstraintIndex{MOI.VariableIndex,S},
+) where {S}
     index = -ci.value
-    return index in eachindex(map.bridges) && !isnothing(map.bridges[index]) && map.sets[index] === S
+    return index in eachindex(map.bridges) &&
+           !isnothing(map.bridges[index]) &&
+           map.sets[index] === S
 end
 
-
 """
     constraints_with_set(map::Map, S::Type{<:MOI.AbstractSet})
 

From 49071cdcfa27f4ef4461480765242e45d04991a9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Tue, 19 Dec 2023 11:44:41 +0100
Subject: [PATCH 09/22] Fixes

---
 src/Bridges/Variable/map.jl  | 2 ++
 test/Bridges/Variable/map.jl | 4 ++++
 2 files changed, 6 insertions(+)

diff --git a/src/Bridges/Variable/map.jl b/src/Bridges/Variable/map.jl
index 7c4dd2344e..080718a117 100644
--- a/src/Bridges/Variable/map.jl
+++ b/src/Bridges/Variable/map.jl
@@ -610,3 +610,5 @@ end
 register_context(::EmptyMap, ::MOI.ConstraintIndex) = nothing
 
 call_in_context(::EmptyMap, ::MOI.ConstraintIndex, f::Function) = f()
+
+MOI.is_valid(::EmptyMap, ::MOI.ConstraintIndex) = false
diff --git a/test/Bridges/Variable/map.jl b/test/Bridges/Variable/map.jl
index a2a7064cde..249fa6099c 100644
--- a/test/Bridges/Variable/map.jl
+++ b/test/Bridges/Variable/map.jl
@@ -271,6 +271,10 @@ function test_EmptyMap()
     @test iszero(MOI.Bridges.Variable.number_with_set(map, S2))
     @test isempty(MOI.Bridges.Variable.constraints_with_set(map, S1))
     @test isempty(MOI.Bridges.Variable.constraints_with_set(map, S2))
+    c1 = MOI.ConstraintIndex{MOI.VariableIndex,S1}(1)
+    @test !MOI.is_valid(map, c1)
+    c2 = MOI.ConstraintIndex{MOI.VectorOfVariables,S2}(1)
+    @test !MOI.is_valid(map, c2)
     @test sprint(show, map) == ""
     return
 end

From fbb81fc688a7e0bdc9d703402776c6401398956d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Tue, 19 Dec 2023 11:54:08 +0100
Subject: [PATCH 10/22] Add doc

---
 src/Bridges/Constraint/map.jl   |  3 +++
 src/Bridges/Variable/map.jl     | 13 +++++++++----
 src/Bridges/bridge_optimizer.jl | 10 ++++++++++
 3 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/src/Bridges/Constraint/map.jl b/src/Bridges/Constraint/map.jl
index c2bd084868..9f6a179db2 100644
--- a/src/Bridges/Constraint/map.jl
+++ b/src/Bridges/Constraint/map.jl
@@ -278,6 +278,9 @@ end
     )
 
 Return a new constraint index `ci` and store the mapping `ci => bridge`.
+If `func isa MOI.VectorOfVariables` then `ci` is such that `is_available(ci)`,
+otherwise, `is_available` is ignored because there can only be a clash of
+indices between variable and constraint bridge mapping for `MOI.VectorOfVariables`.
 """
 function add_key_for_bridge end
 
diff --git a/src/Bridges/Variable/map.jl b/src/Bridges/Variable/map.jl
index 080718a117..9a9c1418c7 100644
--- a/src/Bridges/Variable/map.jl
+++ b/src/Bridges/Variable/map.jl
@@ -382,13 +382,18 @@ function add_key_for_bridge(
 end
 
 """
-    add_keys_for_bridge(map::Map, bridge_fun::Function,
-                        set::MOI.AbstractVectorSet)
+    function add_keys_for_bridge(
+        map::Map,
+        bridge_fun::Function,
+        set::MOI.AbstractVectorSet,
+        is_available::Function,
+    )
 
 Create vector of variable indices `variables`, stores the mapping
 `vi => bridge` for each `vi ∈ variables` and associate `variables` to
-`typeof(set)`. It returns a tuple with `variables` and the constraint index
-`MOI.ConstraintIndex{MOI.VectorOfVariables, typeof(set)}(first(variables).value)`.
+`typeof(set)`. It returns a tuple with `variables` and a constraint index
+`ci::MOI.ConstraintIndex{MOI.VectorOfVariables, typeof(set)}` such that
+`is_available(ci)`.
 """
 function add_keys_for_bridge(
     map::Map,
diff --git a/src/Bridges/bridge_optimizer.jl b/src/Bridges/bridge_optimizer.jl
index 1ef369b881..bfb4a6e064 100644
--- a/src/Bridges/bridge_optimizer.jl
+++ b/src/Bridges/bridge_optimizer.jl
@@ -1716,6 +1716,11 @@ end
 
 function add_bridged_constraint(b, BridgeType, f, s)
     bridge = Constraint.bridge_constraint(BridgeType, recursive_model(b), f, s)
+    # `MOI.VectorOfVariables` constraint indices have negative indices
+    # to distinguish between the indices of the inner model.
+    # However, they can clash between the indices created by the variable
+    # so we use the last argument to inform the constraint bridge mapping about
+    # indices already taken by variable bridges.
     ci = Constraint.add_key_for_bridge(
         Constraint.bridges(b)::Constraint.Map,
         bridge,
@@ -1997,6 +2002,11 @@ function MOI.add_constrained_variables(
     end
     if set isa MOI.Reals || is_variable_bridged(b, typeof(set))
         BridgeType = Variable.concrete_bridge_type(b, typeof(set))
+        # `MOI.VectorOfVariables` constraint indices have negative indices
+        # to distinguish between the indices of the inner model.
+        # However, they can clash between the indices created by the variable
+        # so we use the last argument to inform the variable bridge mapping about
+        # indices already taken by constraint bridges.
         return Variable.add_keys_for_bridge(
             Variable.bridges(b)::Variable.Map,
             () -> Variable.bridge_constrained_variable(BridgeType, b, set),

From 215ca47ca0b11d1d1372b183dff0dad050eff095 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Wed, 20 Dec 2023 09:39:29 +0100
Subject: [PATCH 11/22] Update src/Bridges/Variable/map.jl

Co-authored-by: Oscar Dowson <odow@users.noreply.github.com>
---
 src/Bridges/Variable/map.jl | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/Bridges/Variable/map.jl b/src/Bridges/Variable/map.jl
index 9a9c1418c7..0760f8cd41 100644
--- a/src/Bridges/Variable/map.jl
+++ b/src/Bridges/Variable/map.jl
@@ -408,7 +408,6 @@ function add_keys_for_bridge(
     push!(map.parent_index, map.current_context)
     bridge_index = Int64(length(map.parent_index))
     F = MOI.VectorOfVariables
-    S = typeof(set)
     while !is_available(
         MOI.ConstraintIndex{F,S}(-length(map.vector_of_variables_map) - 1),
     )

From fbe5a73efe5ba6f6ee10cf61df2bd49184ca4458 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Wed, 20 Dec 2023 09:39:37 +0100
Subject: [PATCH 12/22] Update src/Bridges/Variable/map.jl

Co-authored-by: Oscar Dowson <odow@users.noreply.github.com>
---
 src/Bridges/Variable/map.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Bridges/Variable/map.jl b/src/Bridges/Variable/map.jl
index 0760f8cd41..f8a69cb6cc 100644
--- a/src/Bridges/Variable/map.jl
+++ b/src/Bridges/Variable/map.jl
@@ -400,7 +400,7 @@ function add_keys_for_bridge(
     bridge_fun::Function,
     set::MOI.AbstractVectorSet,
     is_available::Function,
-)
+) where {S<:MOI.AbstractVectorSet}
     if iszero(MOI.dimension(set))
         return MOI.VariableIndex[],
         MOI.ConstraintIndex{MOI.VectorOfVariables,typeof(set)}(0)

From c83c215a2dd20b0a0ff479f8b441676e0f90df53 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Wed, 20 Dec 2023 09:39:45 +0100
Subject: [PATCH 13/22] Update src/Bridges/Variable/map.jl

Co-authored-by: Oscar Dowson <odow@users.noreply.github.com>
---
 src/Bridges/Variable/map.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Bridges/Variable/map.jl b/src/Bridges/Variable/map.jl
index f8a69cb6cc..4925f4f1ce 100644
--- a/src/Bridges/Variable/map.jl
+++ b/src/Bridges/Variable/map.jl
@@ -398,7 +398,7 @@ Create vector of variable indices `variables`, stores the mapping
 function add_keys_for_bridge(
     map::Map,
     bridge_fun::Function,
-    set::MOI.AbstractVectorSet,
+    set::S,
     is_available::Function,
 ) where {S<:MOI.AbstractVectorSet}
     if iszero(MOI.dimension(set))

From 0c5091858d0fe46fff3800ca77155ddd78ac4a78 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Wed, 20 Dec 2023 09:42:44 +0100
Subject: [PATCH 14/22] Add doc

---
 src/Bridges/Variable/map.jl | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/Bridges/Variable/map.jl b/src/Bridges/Variable/map.jl
index 4925f4f1ce..5ab978fd58 100644
--- a/src/Bridges/Variable/map.jl
+++ b/src/Bridges/Variable/map.jl
@@ -13,7 +13,8 @@ mutable struct Map <: AbstractDict{MOI.VariableIndex,AbstractBridge}
     # Bridged constrained variables
     # `i` ->  `0`: `VariableIndex(-i)` was added with `add_constrained_variable`.
     # `i` -> `-j`: `VariableIndex(-i)` was the first variable of
-    #              `add_constrained_variables` with a set of dimension `j`.
+    #              `add_constrained_variables` with a
+    #              `ConstraintIndex{MOI.VectorOfVariables}(-j)`.
     # `i` ->  `j`: `VariableIndex(-i)` was the `j`th  variable of
     #             ` add_constrained_variables`.
     info::Vector{Int64}

From 46be39a9ef61a34d0531c9982b1971ea301c0978 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Wed, 20 Dec 2023 10:07:07 +0100
Subject: [PATCH 15/22] Add test and fix bug

---
 src/Bridges/Variable/map.jl           |  6 +++---
 test/Bridges/lazy_bridge_optimizer.jl | 18 +++++++++++++++++-
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/src/Bridges/Variable/map.jl b/src/Bridges/Variable/map.jl
index 5ab978fd58..a93cb69987 100644
--- a/src/Bridges/Variable/map.jl
+++ b/src/Bridges/Variable/map.jl
@@ -417,7 +417,8 @@ function add_keys_for_bridge(
     end
     push!(map.vector_of_variables_map, -bridge_index)
     push!(map.vector_of_variables_length, MOI.dimension(set))
-    push!(map.info, -length(map.vector_of_variables_length))
+    constraint_index = -length(map.vector_of_variables_map)
+    push!(map.info, constraint_index)
     push!(map.index_in_vector, 1)
     push!(map.bridges, nothing)
     push!(map.sets, typeof(set))
@@ -446,8 +447,7 @@ function add_keys_for_bridge(
             end
         end
     end
-    return variables,
-    MOI.ConstraintIndex{F,S}(-length(map.vector_of_variables_map))
+    return variables, MOI.ConstraintIndex{F,S}(constraint_index)
 end
 
 """
diff --git a/test/Bridges/lazy_bridge_optimizer.jl b/test/Bridges/lazy_bridge_optimizer.jl
index 57ce1f38c3..69c094a29d 100644
--- a/test/Bridges/lazy_bridge_optimizer.jl
+++ b/test/Bridges/lazy_bridge_optimizer.jl
@@ -332,7 +332,7 @@ function test_MOI_runtests_GeometricSDPAModel()
     return
 end
 
-function test_index_conflict()
+function test_index_constraint_conflict()
     optimizer = StandardSDPAModel{Float64}()
     model = MOI.Bridges.full_bridge_optimizer(optimizer, Float64)
     x, cx = MOI.add_constrained_variables(model, MOI.Nonpositives(1))
@@ -348,6 +348,22 @@ function test_index_conflict()
     @test c != b2.slack_in_set
 end
 
+function test_index_variable_conflict()
+    optimizer = StandardSDPAModel{Float64}()
+    model = MOI.Bridges.full_bridge_optimizer(optimizer, Float64)
+    set = MOI.SecondOrderCone(3)
+    x = MOI.add_variables(model, 3)
+    c = MOI.add_constraint(model, MOI.VectorOfVariables(x), set)
+    @test MOI.is_valid(model, c)
+    y, cy = MOI.add_constrained_variables(model, set)
+    @test MOI.is_valid(model, cy)
+    @test cy != c
+    z, cz = MOI.add_constrained_variables(model, set)
+    @test MOI.is_valid(model, cz)
+    @test cz != c
+end
+
+
 function test_show_SPDA()
     model = StandardSDPAModel{Float64}()
     model_str = sprint(MOI.Utilities.print_with_acronym, string(typeof(model)))

From d1d6b1e703017576f7a6907a52e8ad2649965f22 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Wed, 20 Dec 2023 10:14:48 +0100
Subject: [PATCH 16/22] Fix format

---
 test/Bridges/lazy_bridge_optimizer.jl | 1 -
 1 file changed, 1 deletion(-)

diff --git a/test/Bridges/lazy_bridge_optimizer.jl b/test/Bridges/lazy_bridge_optimizer.jl
index 69c094a29d..db5d0005bb 100644
--- a/test/Bridges/lazy_bridge_optimizer.jl
+++ b/test/Bridges/lazy_bridge_optimizer.jl
@@ -363,7 +363,6 @@ function test_index_variable_conflict()
     @test cz != c
 end
 
-
 function test_show_SPDA()
     model = StandardSDPAModel{Float64}()
     model_str = sprint(MOI.Utilities.print_with_acronym, string(typeof(model)))

From 162e3631dcfbcb39155f6a07466f9115eaf0ebd7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Wed, 20 Dec 2023 14:25:09 +0100
Subject: [PATCH 17/22] Add first_variable to fix bugs

---
 src/Bridges/Variable/map.jl      |  8 ++++++++
 src/Bridges/bridge_optimizer.jl  | 10 +++++-----
 test/Bridges/bridge_optimizer.jl | 29 +++++++++++++++++++++++++++++
 3 files changed, 42 insertions(+), 5 deletions(-)

diff --git a/src/Bridges/Variable/map.jl b/src/Bridges/Variable/map.jl
index a93cb69987..e7a5b44fdb 100644
--- a/src/Bridges/Variable/map.jl
+++ b/src/Bridges/Variable/map.jl
@@ -219,6 +219,14 @@ function number_with_set(map::Map, S::Type{<:MOI.AbstractSet})
     return count(isequal(S), map.sets)
 end
 
+function first_variable(::Map, ci::MOI.ConstraintIndex{MOI.VariableIndex})
+    return MOI.VariableIndex(ci.value)
+end
+
+function first_variable(map::Map, ci::MOI.ConstraintIndex{MOI.VectorOfVariables})
+    return MOI.VariableIndex(map.vector_of_variables_map[-ci.value])
+end
+
 function constraint(map::Map, vi::MOI.VariableIndex)
     S = constrained_set(map, vi)::Type{<:MOI.AbstractSet}
     F = MOI.Utilities.variable_function_type(S)
diff --git a/src/Bridges/bridge_optimizer.jl b/src/Bridges/bridge_optimizer.jl
index bfb4a6e064..67b5661732 100644
--- a/src/Bridges/bridge_optimizer.jl
+++ b/src/Bridges/bridge_optimizer.jl
@@ -261,7 +261,8 @@ Return the `AbstractBridge` used to bridge the constraint with index `ci`.
 """
 function bridge(b::AbstractBridgeOptimizer, ci::MOI.ConstraintIndex)
     if is_variable_bridged(b, ci)
-        return bridge(b, MOI.VariableIndex(ci.value))
+        map = Variable.bridges(b)::Variable.Map
+        return bridge(b, Variable.first_variable(map, ci))
     else
         return Constraint.bridges(b)[ci]
     end
@@ -312,7 +313,8 @@ function call_in_context(
     f::Function,
 )
     if is_variable_bridged(b, ci)
-        return call_in_context(b, MOI.VariableIndex(ci.value), f)
+        map = Variable.bridges(b)::Variable.Map
+        return call_in_context(b, Variable.first_variable(map, ci), f)
     else
         return Variable.call_in_context(
             Variable.bridges(b),
@@ -483,10 +485,8 @@ function MOI.is_valid(
 ) where {F,S}
     if is_bridged(b, ci)
         if is_variable_bridged(b, ci)
-            vi = MOI.VariableIndex(ci.value)
             v_map = Variable.bridges(b)::Variable.Map
-            return MOI.is_valid(b, vi) &&
-                   Variable.constrained_set(v_map, vi) == S
+            return MOI.is_valid(v_map, ci)
         else
             return haskey(Constraint.bridges(b), ci)
         end
diff --git a/test/Bridges/bridge_optimizer.jl b/test/Bridges/bridge_optimizer.jl
index 2e8df8af12..daf11fffe3 100644
--- a/test/Bridges/bridge_optimizer.jl
+++ b/test/Bridges/bridge_optimizer.jl
@@ -1129,6 +1129,35 @@ function test_first_bridge()
     return
 end
 
+function test_variable_bridge_constraint_attribute()
+    mock = MOI.Utilities.MockOptimizer(
+        MOI.Utilities.UniversalFallback(MOI.Utilities.Model{Float64}()),
+    )
+    model = MOI.Bridges.Variable.NonposToNonneg{Float64}(mock)
+    x, cx = MOI.add_constrained_variables(model, MOI.Nonpositives(2))
+    y, cy = MOI.add_constrained_variables(model, MOI.Nonpositives(2))
+    @test MOI.Bridges.bridge(model, x[1]) === MOI.Bridges.bridge(model, cx)
+    @test MOI.Bridges.bridge(model, x[2]) === MOI.Bridges.bridge(model, cx)
+    @test MOI.Bridges.bridge(model, y[1]) === MOI.Bridges.bridge(model, cy)
+    @test MOI.Bridges.bridge(model, y[2]) === MOI.Bridges.bridge(model, cy)
+    var = [x; y]
+    val = float.(collect(1:4))
+    mock_var = MOI.get(mock, MOI.ListOfVariableIndices())
+    MOI.set(mock, MOI.VariablePrimal(), mock_var, -val)
+    @test MOI.get(model, MOI.VariablePrimal(), var) == val
+    @test MOI.get(model, MOI.ConstraintPrimal(), cx) == val[1:2]
+    @test MOI.get(model, MOI.ConstraintPrimal(), cy) == val[3:4]
+    for v in var
+        @test MOI.is_valid(model, v)
+    end
+    @test MOI.is_valid(model, cx)
+    @test MOI.is_valid(model, cy)
+    MOI.delete(model, x)
+    @test !MOI.is_valid(model, cx)
+    @test MOI.is_valid(model, cy)
+    return
+end
+
 end  # module
 
 TestBridgeOptimizer.runtests()

From 92c0240ccf28e0293bb0bb20d24fa86e6d316a5a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Wed, 20 Dec 2023 14:41:45 +0100
Subject: [PATCH 18/22] Fix format

---
 src/Bridges/Variable/map.jl | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/Bridges/Variable/map.jl b/src/Bridges/Variable/map.jl
index e7a5b44fdb..9384e8265d 100644
--- a/src/Bridges/Variable/map.jl
+++ b/src/Bridges/Variable/map.jl
@@ -223,7 +223,10 @@ function first_variable(::Map, ci::MOI.ConstraintIndex{MOI.VariableIndex})
     return MOI.VariableIndex(ci.value)
 end
 
-function first_variable(map::Map, ci::MOI.ConstraintIndex{MOI.VectorOfVariables})
+function first_variable(
+    map::Map,
+    ci::MOI.ConstraintIndex{MOI.VectorOfVariables},
+)
     return MOI.VariableIndex(map.vector_of_variables_map[-ci.value])
 end
 

From b22d380f94dceff8ad775787881587227661dd7a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Wed, 20 Dec 2023 14:45:38 +0100
Subject: [PATCH 19/22] Add docstrings

---
 src/Bridges/Variable/map.jl | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/Bridges/Variable/map.jl b/src/Bridges/Variable/map.jl
index 9384e8265d..8f18f3edb6 100644
--- a/src/Bridges/Variable/map.jl
+++ b/src/Bridges/Variable/map.jl
@@ -219,10 +219,20 @@ function number_with_set(map::Map, S::Type{<:MOI.AbstractSet})
     return count(isequal(S), map.sets)
 end
 
+"""
+    first_variable(::Map, ci::MOI.ConstraintIndex{MOI.VariableIndex})
+
+Return the `MOI.VariableIndex` of the `MOI.ConstraintFunction` of `ci`.
+"""
 function first_variable(::Map, ci::MOI.ConstraintIndex{MOI.VariableIndex})
     return MOI.VariableIndex(ci.value)
 end
 
+"""
+    first_variable(::Map, ci::MOI.ConstraintIndex{MOI.VariableIndex})
+
+Return the first `MOI.VariableIndex` of the `MOI.ConstraintFunction` of `ci`.
+"""
 function first_variable(
     map::Map,
     ci::MOI.ConstraintIndex{MOI.VectorOfVariables},

From 38ab2acdc44031478cfab9de6dab17f08b1c71db Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Thu, 21 Dec 2023 10:17:05 +0100
Subject: [PATCH 20/22] Add tests

---
 test/Bridges/lazy_bridge_optimizer.jl | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/test/Bridges/lazy_bridge_optimizer.jl b/test/Bridges/lazy_bridge_optimizer.jl
index db5d0005bb..7fd27065fd 100644
--- a/test/Bridges/lazy_bridge_optimizer.jl
+++ b/test/Bridges/lazy_bridge_optimizer.jl
@@ -348,13 +348,15 @@ function test_index_constraint_conflict()
     @test c != b2.slack_in_set
 end
 
-function test_index_variable_conflict()
+function _test_index_variable_conflict(set)
     optimizer = StandardSDPAModel{Float64}()
     model = MOI.Bridges.full_bridge_optimizer(optimizer, Float64)
-    set = MOI.SecondOrderCone(3)
-    x = MOI.add_variables(model, 3)
+    x = MOI.add_variables(model, MOI.dimension(set))
     c = MOI.add_constraint(model, MOI.VectorOfVariables(x), set)
     @test MOI.is_valid(model, c)
+    w, cw = MOI.add_constrained_variables(model, set)
+    @test MOI.is_valid(model, cw)
+    @test cw != c
     y, cy = MOI.add_constrained_variables(model, set)
     @test MOI.is_valid(model, cy)
     @test cy != c
@@ -363,6 +365,16 @@ function test_index_variable_conflict()
     @test cz != c
 end
 
+function test_index_variable_conflict()
+    _test_index_variable_conflict(MOI.Nonpositives(3))
+    _test_index_variable_conflict(MOI.SecondOrderCone(3))
+    _test_index_variable_conflict(MOI.RotatedSecondOrderCone(3))
+    _test_index_variable_conflict(MOI.RotatedSecondOrderCone(2))
+    return _test_index_variable_conflict(
+        MOI.ScaledPositiveSemidefiniteConeTriangle(2),
+    )
+end
+
 function test_show_SPDA()
     model = StandardSDPAModel{Float64}()
     model_str = sprint(MOI.Utilities.print_with_acronym, string(typeof(model)))

From d49f5b930bea94d1c1851b678420dec8dcb268fa Mon Sep 17 00:00:00 2001
From: Oscar Dowson <odow@users.noreply.github.com>
Date: Fri, 22 Dec 2023 08:57:04 +1300
Subject: [PATCH 21/22] Update lazy_bridge_optimizer.jl

---
 test/Bridges/lazy_bridge_optimizer.jl | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/test/Bridges/lazy_bridge_optimizer.jl b/test/Bridges/lazy_bridge_optimizer.jl
index 7fd27065fd..50a765f27f 100644
--- a/test/Bridges/lazy_bridge_optimizer.jl
+++ b/test/Bridges/lazy_bridge_optimizer.jl
@@ -346,6 +346,7 @@ function test_index_constraint_conflict()
     b1 = MOI.Bridges.bridge(model, c)
     b2 = MOI.Bridges.bridge(model, b1.constraint)
     @test c != b2.slack_in_set
+    return
 end
 
 function _test_index_variable_conflict(set)
@@ -363,6 +364,7 @@ function _test_index_variable_conflict(set)
     z, cz = MOI.add_constrained_variables(model, set)
     @test MOI.is_valid(model, cz)
     @test cz != c
+    return
 end
 
 function test_index_variable_conflict()
@@ -370,9 +372,10 @@ function test_index_variable_conflict()
     _test_index_variable_conflict(MOI.SecondOrderCone(3))
     _test_index_variable_conflict(MOI.RotatedSecondOrderCone(3))
     _test_index_variable_conflict(MOI.RotatedSecondOrderCone(2))
-    return _test_index_variable_conflict(
+    _test_index_variable_conflict(
         MOI.ScaledPositiveSemidefiniteConeTriangle(2),
     )
+    return
 end
 
 function test_show_SPDA()

From a9bbfbbe959501745d5bf14c553c57a36f439fcd Mon Sep 17 00:00:00 2001
From: Oscar Dowson <odow@users.noreply.github.com>
Date: Fri, 22 Dec 2023 09:21:27 +1300
Subject: [PATCH 22/22] Update lazy_bridge_optimizer.jl

---
 test/Bridges/lazy_bridge_optimizer.jl | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/test/Bridges/lazy_bridge_optimizer.jl b/test/Bridges/lazy_bridge_optimizer.jl
index 50a765f27f..327f1b2289 100644
--- a/test/Bridges/lazy_bridge_optimizer.jl
+++ b/test/Bridges/lazy_bridge_optimizer.jl
@@ -372,9 +372,7 @@ function test_index_variable_conflict()
     _test_index_variable_conflict(MOI.SecondOrderCone(3))
     _test_index_variable_conflict(MOI.RotatedSecondOrderCone(3))
     _test_index_variable_conflict(MOI.RotatedSecondOrderCone(2))
-    _test_index_variable_conflict(
-        MOI.ScaledPositiveSemidefiniteConeTriangle(2),
-    )
+    _test_index_variable_conflict(MOI.ScaledPositiveSemidefiniteConeTriangle(2))
     return
 end