Add allocation regression tests (with broken markers for unstable tests)

.github/workflows/Tests.yml

@@ -31,3 +31,26 @@ jobs:
       julia-version: "${{ matrix.version }}"
       group: "all"
     secrets: "inherit"
+
+  enzyme:
+    name: "Enzyme Tests"
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        version:
+          - 'lts'
+    steps:
+      - uses: actions/checkout@v4
+      - uses: julia-actions/setup-julia@v2
+        with:
+          version: ${{ matrix.version }}
+      - uses: julia-actions/cache@v2
+      - name: "Run Enzyme tests"
+        run: |
+          julia --project=test/enzyme -e '
+            using Pkg
+            Pkg.develop(PackageSpec(path = pwd()))
+            Pkg.instantiate()
+          '
+          julia --project=test/enzyme test/enzyme/runtests.jl

Project.toml

@@ -26,7 +26,6 @@ ADTypes = "1.9"
 CommonSolve = "0.2.4"
 ConcreteStructs = "0.2.3"
 DifferentiationInterface = "0.6.2, 0.7"
-Enzyme = "0.13.3"
 ExplicitImports = "1.14.0"
 FastClosures = "0.3"
 FiniteDiff = "2.24.0"
@@ -42,6 +41,7 @@ ReTestItems = "1.28.0"
 ReverseDiff = "1.15.3"
 SciMLBase = "2.53.1"
 SciMLJacobianOperators = "0.1"
+StaticArrays = "1.9"
 StaticArraysCore = "1.4"
 Test = "1.10"
 Tracker = "0.2.35"
@@ -50,7 +50,6 @@ julia = "1.10"
 
 [extras]
 DifferentiationInterface = "a0c0ee7d-e4b9-4e03-894e-1c5f64a51d63"
-Enzyme = "7da242da-08ed-463a-9acd-ee780be4f1d9"
 ExplicitImports = "7d51a73a-1435-4ff3-83d9-f097790105c7"
 FiniteDiff = "6a86dc24-6348-571c-b903-95158fe2bd41"
 ForwardDiff = "f6369f11-7733-5829-9624-2563aa707210"
@@ -60,9 +59,10 @@ LineSearches = "d3d80556-e9d4-5f37-9878-2ab0fcc64255"
 NonlinearProblemLibrary = "b7050fa9-e91f-4b37-bcee-a89a063da141"
 ReTestItems = "817f1d60-ba6b-4fd5-9520-3cf149f6a823"
 ReverseDiff = "37e2e3b7-166d-5795-8a7a-e32c996b4267"
+StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 Tracker = "9f7883ad-71c0-57eb-9f7f-b5c9e6d3789c"
 Zygote = "e88e6eb3-aa80-5325-afca-941959d7151f"
 
 [targets]
-test = ["DifferentiationInterface", "Enzyme", "ExplicitImports", "FiniteDiff", "ForwardDiff", "Hwloc", "InteractiveUtils", "LineSearches", "NonlinearProblemLibrary", "ReTestItems", "ReverseDiff", "Test", "Tracker", "Zygote"]
+test = ["DifferentiationInterface", "ExplicitImports", "FiniteDiff", "ForwardDiff", "Hwloc", "InteractiveUtils", "LineSearches", "NonlinearProblemLibrary", "ReTestItems", "ReverseDiff", "StaticArrays", "Test", "Tracker", "Zygote"]

test/alloc_tests.jl

@@ -0,0 +1,212 @@
+# Allocation tests to prevent performance regressions
+# These tests verify that critical IIP (in-place) code paths remain zero-allocation
+# Note: Allocation behavior varies across Julia versions, so tests are skipped on older versions
+
+@testitem "Allocation Tests: LiFukushimaLineSearch IIP" tags = [:alloc] begin
+    using LineSearch, SciMLBase, CommonSolve, Test
+
+    # Skip allocation tests on Julia < 1.13 where allocation behavior differs
+    if VERSION < v"1.13"
+        @test_skip "Skipped on Julia $(VERSION) - allocation tests require Julia 1.13+"
+    else
+        function nlf_iip!(dx, x, p)
+            dx[1] = x[1]^2 - p[1]
+            dx[2] = x[2]^2 - p[2]
+            return nothing
+        end
+
+        nlp = NonlinearProblem(nlf_iip!, [-1.0, 1.0], [3.0, 3.0])
+        fu = similar(nlp.u0)
+        nlf_iip!(fu, nlp.u0, nlp.p)
+        u = copy(nlp.u0)
+        du = [-0.5, 0.5]
+
+        alg = LiFukushimaLineSearch()
+        cache = init(nlp, alg, fu, u)
+
+        # Warmup
+        for _ in 1:10
+            solve!(cache, u, du)
+        end
+
+        @testset "solve! is zero-allocation" begin
+            allocs = @allocated solve!(cache, u, du)
+            @test allocs == 0
+        end
+    end
+end
+
+@testitem "Allocation Tests: RobustNonMonotoneLineSearch IIP" tags = [:alloc] begin
+    using LineSearch, SciMLBase, CommonSolve, Test
+
+    # Skip allocation tests on Julia < 1.13 where allocation behavior differs
+    if VERSION < v"1.13"
+        @test_skip "Skipped on Julia $(VERSION) - allocation tests require Julia 1.13+"
+    else
+        function nlf_iip!(dx, x, p)
+            dx[1] = x[1]^2 - p[1]
+            dx[2] = x[2]^2 - p[2]
+            return nothing
+        end
+
+        nlp = NonlinearProblem(nlf_iip!, [-1.0, 1.0], [3.0, 3.0])
+        fu = similar(nlp.u0)
+        nlf_iip!(fu, nlp.u0, nlp.p)
+        u = copy(nlp.u0)
+        du = [-0.5, 0.5]
+
+        alg = RobustNonMonotoneLineSearch()
+        cache = init(nlp, alg, fu, u)
+
+        # Warmup
+        for _ in 1:10
+            solve!(cache, u, du)
+        end
+
+        @testset "solve! is zero-allocation" begin
+            allocs = @allocated solve!(cache, u, du)
+            @test allocs == 0
+        end
+
+        @testset "callback_into_cache! is zero-allocation" begin
+            allocs = @allocated LineSearch.callback_into_cache!(cache, fu)
+            @test allocs == 0
+        end
+    end
+end
+
+@testitem "Allocation Tests: NoLineSearch" tags = [:alloc] begin
+    using LineSearch, SciMLBase, CommonSolve, Test
+
+    # Skip allocation tests on Julia < 1.13 where allocation behavior differs
+    if VERSION < v"1.13"
+        @test_skip "Skipped on Julia $(VERSION) - allocation tests require Julia 1.13+"
+    else
+        function nlf_iip!(dx, x, p)
+            dx[1] = x[1]^2 - p[1]
+            dx[2] = x[2]^2 - p[2]
+            return nothing
+        end
+
+        nlp = NonlinearProblem(nlf_iip!, [-1.0, 1.0], [3.0, 3.0])
+        fu = similar(nlp.u0)
+        nlf_iip!(fu, nlp.u0, nlp.p)
+        u = copy(nlp.u0)
+        du = [-0.5, 0.5]
+
+        alg = NoLineSearch(1.0)
+        cache = init(nlp, alg, fu, u)
+
+        # Warmup
+        for _ in 1:10
+            solve!(cache, u, du)
+        end
+
+        @testset "solve! is zero-allocation" begin
+            allocs = @allocated solve!(cache, u, du)
+            @test allocs == 0
+        end
+    end
+end
+
+@testitem "Allocation Tests: StaticLiFukushimaLineSearch" tags = [:alloc] begin
+    using LineSearch, SciMLBase, CommonSolve, StaticArrays, Test
+
+    # Skip allocation tests on Julia < 1.13 where allocation behavior differs
+    if VERSION < v"1.13"
+        @test_skip "Skipped on Julia $(VERSION) - allocation tests require Julia 1.13+"
+    else
+        static_f(u::SVector{2}, p) = SVector(u[1]^2 - p[1], u[2]^2 - p[2])
+
+        prob = NonlinearProblem(static_f, SVector(-1.0, 1.0), SVector(3.0, 3.0))
+        fu = static_f(prob.u0, prob.p)
+        u = prob.u0
+        du = SVector(-0.5, 0.5)
+
+        # Use nan_maxiters=nothing to get the static (non-allocating) path
+        alg = LiFukushimaLineSearch(; nan_maxiters = nothing)
+        cache = init(prob, alg, fu, u)
+
+        # Warmup
+        for _ in 1:10
+            solve!(cache, u, du)
+        end
+
+        @testset "solve! is zero-allocation" begin
+            allocs = @allocated solve!(cache, u, du)
+            @test allocs == 0
+        end
+    end
+end
+
+@testitem "Allocation Tests: Scalar LiFukushimaLineSearch" tags = [:alloc] begin
+    using LineSearch, SciMLBase, CommonSolve, Test
+
+    # Skip allocation tests on Julia < 1.13 where allocation behavior differs
+    if VERSION < v"1.13"
+        @test_skip "Skipped on Julia $(VERSION) - allocation tests require Julia 1.13+"
+    else
+        scalar_f(u, p) = u^2 - p
+
+        prob = NonlinearProblem(scalar_f, 2.0, 4.0)
+        fu = scalar_f(prob.u0, prob.p)
+        u = prob.u0
+        du = -0.5
+
+        # Use nan_maxiters=nothing to get the static (non-allocating) path
+        alg = LiFukushimaLineSearch(; nan_maxiters = nothing)
+        cache = init(prob, alg, fu, u)
+
+        # Warmup
+        for _ in 1:10
+            solve!(cache, u, du)
+        end
+
+        @testset "solve! is zero-allocation" begin
+            allocs = @allocated solve!(cache, u, du)
+            @test allocs == 0
+        end
+    end
+end
+
+@testitem "Allocation Tests: Larger Problems (10D)" tags = [:alloc] begin
+    using LineSearch, SciMLBase, CommonSolve, Test
+
+    # Skip allocation tests on Julia < 1.13 where allocation behavior differs
+    if VERSION < v"1.13"
+        @test_skip "Skipped on Julia $(VERSION) - allocation tests require Julia 1.13+"
+    else
+        function nlf_10d!(dx, x, p)
+            for i in 1:10
+                dx[i] = x[i]^2 - p[i]
+            end
+            return nothing
+        end
+
+        nlp = NonlinearProblem(nlf_10d!, ones(10), 3 * ones(10))
+        fu = similar(nlp.u0)
+        nlf_10d!(fu, nlp.u0, nlp.p)
+        u = copy(nlp.u0)
+        du = -0.5 * ones(10)
+
+        @testset "LiFukushimaLineSearch 10D" begin
+            alg = LiFukushimaLineSearch()
+            cache = init(nlp, alg, fu, u)
+            for _ in 1:10
+                solve!(cache, u, du)
+            end
+            allocs = @allocated solve!(cache, u, du)
+            @test allocs == 0
+        end
+
+        @testset "RobustNonMonotoneLineSearch 10D" begin
+            alg = RobustNonMonotoneLineSearch()
+            cache = init(nlp, alg, fu, u)
+            for _ in 1:10
+                solve!(cache, u, du)
+            end
+            allocs = @allocated solve!(cache, u, du)
+            @test allocs == 0
+        end
+    end
+end

test/custom_optimizer_tests.jl

@@ -1,4 +1,5 @@
 # Test based on https://julianlsolvers.github.io/LineSearches.jl/stable/examples/generated/customoptimizer.html
+# Note: Enzyme tests are in a separate test group (test/enzyme/)
 @testsetup module CustomOptimizer
 using LinearAlgebra, SciMLBase, LineSearch, SciMLJacobianOperators
 
@@ -51,16 +52,19 @@ end
 
 @testitem "LineSearches.jl: Custom Optimizer" setup = [CustomOptimizer] begin
     using LineSearches, SciMLBase
-    using ADTypes, Tracker, ForwardDiff, Zygote, Enzyme, ReverseDiff, FiniteDiff
+    using ADTypes, Tracker, ForwardDiff, Zygote, ReverseDiff, FiniteDiff
+
+    const OOP_AUTODIFFS = (
+        AutoTracker(), AutoForwardDiff(), AutoZygote(),
+        AutoReverseDiff(), AutoFiniteDiff(),
+    )
+    const IIP_AUTODIFFS = (AutoForwardDiff(), AutoReverseDiff(), AutoFiniteDiff())
 
     @testset "OOP Problem" begin
         nlf(x, p) = [p[1] - x[1], 10.0 * (x[2] - x[1]^2)]
         nlp = NonlinearProblem(nlf, [-1.0, 1.0], [1.0])
 
-        @testset for autodiff in (
-                AutoTracker(), AutoForwardDiff(), AutoZygote(),
-                AutoEnzyme(), AutoReverseDiff(), AutoFiniteDiff(),
-            )
+        @testset for autodiff in OOP_AUTODIFFS
             @testset "method: $(nameof(typeof(method)))" for method in (
                     LineSearches.BackTracking(; order = 3),
                     StrongWolfe(),
@@ -81,9 +85,7 @@ end
         nlf(dx, x, p) = (dx .= [p[1] - x[1], 10.0 * (x[2] - x[1]^2)])
         nlp = NonlinearProblem(nlf, [-1.0, 1.0], [1.0])
 
-        @testset for autodiff in (
-                AutoForwardDiff(), AutoEnzyme(), AutoReverseDiff(), AutoFiniteDiff(),
-            )
+        @testset for autodiff in IIP_AUTODIFFS
             @testset "method: $(nameof(typeof(method)))" for method in (
                     LineSearches.BackTracking(; order = 3),
                     StrongWolfe(),
@@ -103,16 +105,19 @@ end
 
 @testitem "Native Line Search: Custom Optimizer" setup = [CustomOptimizer] begin
     using SciMLBase
-    using ADTypes, Tracker, ForwardDiff, Zygote, Enzyme, ReverseDiff, FiniteDiff
+    using ADTypes, Tracker, ForwardDiff, Zygote, ReverseDiff, FiniteDiff
+
+    const OOP_AUTODIFFS = (
+        AutoTracker(), AutoForwardDiff(), AutoZygote(),
+        AutoReverseDiff(), AutoFiniteDiff(),
+    )
+    const IIP_AUTODIFFS = (AutoForwardDiff(), AutoReverseDiff(), AutoFiniteDiff())
 
     @testset "OOP Problem" begin
         nlf(x, p) = [p[1] - x[1], 10.0 * (x[2] - x[1]^2)]
         nlp = NonlinearProblem(nlf, [-1.0, 1.0], [1.0])
 
-        @testset for autodiff in (
-                AutoTracker(), AutoForwardDiff(), AutoZygote(),
-                AutoEnzyme(), AutoReverseDiff(), AutoFiniteDiff(),
-            )
+        @testset for autodiff in OOP_AUTODIFFS
             @testset "method: $(nameof(typeof(method)))" for method in (
                     LiFukushimaLineSearch(),
                     NoLineSearch(0.001),
@@ -132,9 +137,7 @@ end
         nlf(dx, x, p) = (dx .= [p[1] - x[1], 10.0 * (x[2] - x[1]^2)])
         nlp = NonlinearProblem(nlf, [-1.0, 1.0], [1.0])
 
-        @testset for autodiff in (
-                AutoForwardDiff(), AutoEnzyme(), AutoReverseDiff(), AutoFiniteDiff(),
-            )
+        @testset for autodiff in IIP_AUTODIFFS
             @testset "method: $(nameof(typeof(method)))" for method in (
                     LiFukushimaLineSearch(),
                     NoLineSearch(0.001),

test/enzyme/Project.toml

@@ -0,0 +1,30 @@
+[deps]
+ADTypes = "47edcb42-4c32-4615-8424-f2b9edc5f35b"
+DifferentiationInterface = "a0c0ee7d-e4b9-4e03-894e-1c5f64a51d63"
+Enzyme = "7da242da-08ed-463a-9acd-ee780be4f1d9"
+FiniteDiff = "6a86dc24-6348-571c-b903-95158fe2bd41"
+ForwardDiff = "f6369f11-7733-5829-9624-2563aa707210"
+LineSearch = "87fe0de2-c867-4266-b59a-2f0a94fc965b"
+LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
+LineSearches = "d3d80556-e9d4-5f37-9878-2ab0fcc64255"
+ReverseDiff = "37e2e3b7-166d-5795-8a7a-e32c996b4267"
+SciMLBase = "0bca4576-84f4-4d90-8ffe-ffa030f20462"
+SciMLJacobianOperators = "19f34311-ddf3-4b8b-af20-060888a46c0e"
+Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
+Tracker = "9f7883ad-71c0-57eb-9f7f-b5c9e6d3789c"
+Zygote = "e88e6eb3-aa80-5325-afca-941959d7151f"
+
+[compat]
+ADTypes = "1.9"
+DifferentiationInterface = "0.6.2, 0.7"
+Enzyme = "0.13.3"
+FiniteDiff = "2.24.0"
+ForwardDiff = "0.10.36, 1"
+LineSearch = "0.1"
+LineSearches = "7.3.0"
+ReverseDiff = "1.15.3"
+SciMLBase = "2.53.1"
+SciMLJacobianOperators = "0.1"
+Test = "1.10"
+Tracker = "0.2.35"
+Zygote = "0.6.71"