From 151ad470265c562555e65aae3ceec32beb1d9b54 Mon Sep 17 00:00:00 2001
From: Guillaume Dalle <22795598+gdalle@users.noreply.github.com>
Date: Thu, 29 Jan 2026 10:02:24 +0100
Subject: [PATCH 1/9] fix: upgrade Mooncake compat to v0.5

---
 DifferentiationInterface/CHANGELOG.md                     | 8 +++++++-
 DifferentiationInterface/Project.toml                     | 4 ++--
 .../DifferentiationInterfaceMooncakeExt/forward_onearg.jl | 2 +-
 .../DifferentiationInterfaceMooncakeExt/forward_twoarg.jl | 3 +--
 .../ext/DifferentiationInterfaceMooncakeExt/onearg.jl     | 4 ++--
 .../ext/DifferentiationInterfaceMooncakeExt/twoarg.jl     | 3 +--
 6 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/DifferentiationInterface/CHANGELOG.md b/DifferentiationInterface/CHANGELOG.md
index f01ae3b2a..d60b733ec 100644
--- a/DifferentiationInterface/CHANGELOG.md
+++ b/DifferentiationInterface/CHANGELOG.md
@@ -5,7 +5,13 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [Unreleased](https://github.com/JuliaDiff/DifferentiationInterface.jl/compare/DifferentiationInterface-v0.7.15...main)
+## [Unreleased](https://github.com/JuliaDiff/DifferentiationInterface.jl/compare/DifferentiationInterface-v0.7.16...main)
+
+## [0.7.16](https://github.com/JuliaDiff/DifferentiationInterface.jl/compare/DifferentiationInterface-v0.7.15...DifferentiationInterface-v0.7.16)
+
+### Fixed
+
+- Upgrade Mooncake compat to v0.5 ([#961](https://github.com/JuliaDiff/DifferentiationInterface.jl/pull/961))
 
 ## [0.7.15](https://github.com/JuliaDiff/DifferentiationInterface.jl/compare/DifferentiationInterface-v0.7.14...DifferentiationInterface-v0.7.15)
 
diff --git a/DifferentiationInterface/Project.toml b/DifferentiationInterface/Project.toml
index d50bdcf11..f54fd1f4f 100644
--- a/DifferentiationInterface/Project.toml
+++ b/DifferentiationInterface/Project.toml
@@ -1,7 +1,7 @@
 name = "DifferentiationInterface"
 uuid = "a0c0ee7d-e4b9-4e03-894e-1c5f64a51d63"
 authors = ["Guillaume Dalle", "Adrian Hill"]
-version = "0.7.15"
+version = "0.7.16"
 
 [deps]
 ADTypes = "47edcb42-4c32-4615-8424-f2b9edc5f35b"
@@ -69,7 +69,7 @@ ForwardDiff = "0.10.36,1"
 GPUArraysCore = "0.2"
 GTPSA = "1.4.0"
 LinearAlgebra = "1"
-Mooncake = "0.4.175"
+Mooncake = "0.5.0"
 PolyesterForwardDiff = "0.1.2"
 ReverseDiff = "1.15.1"
 SparseArrays = "1"
diff --git a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_onearg.jl b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_onearg.jl
index 61946a0d3..b64549b89 100644
--- a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_onearg.jl
+++ b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_onearg.jl
@@ -19,7 +19,7 @@ function DI.prepare_pushforward_nokwarg(
     _sig = DI.signature(f, backend, x, tx, contexts...; strict)
     config = get_config(backend)
     cache = prepare_derivative_cache(
-        f, x, map(DI.unwrap, contexts)...; config.debug_mode, config.silence_debug_messages
+        f, x, map(DI.unwrap, contexts)...; config
     )
     dx_righttype = zero_tangent(x)
     df = zero_tangent(f)
diff --git a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl
index dc8f8c1f0..dea6138bc 100644
--- a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl
+++ b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl
@@ -25,8 +25,7 @@ function DI.prepare_pushforward_nokwarg(
         y,
         x,
         map(DI.unwrap, contexts)...;
-        config.debug_mode,
-        config.silence_debug_messages,
+        config
     )
     dx_righttype = zero_tangent(x)
     dy_righttype = zero_tangent(y)
diff --git a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/onearg.jl b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/onearg.jl
index ab9818735..e52a2a498 100644
--- a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/onearg.jl
+++ b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/onearg.jl
@@ -13,7 +13,7 @@ function DI.prepare_pullback_nokwarg(
     _sig = DI.signature(f, backend, x, ty, contexts...; strict)
     config = get_config(backend)
     cache = prepare_pullback_cache(
-        f, x, map(DI.unwrap, contexts)...; config.debug_mode, config.silence_debug_messages
+        f, x, map(DI.unwrap, contexts)...; config
     )
     y = f(x, map(DI.unwrap, contexts)...)
     dy_righttype = zero_tangent(y)
@@ -122,7 +122,7 @@ function DI.prepare_gradient_nokwarg(
     _sig = DI.signature(f, backend, x, contexts...; strict)
     config = get_config(backend)
     cache = prepare_gradient_cache(
-        f, x, map(DI.unwrap, contexts)...; config.debug_mode, config.silence_debug_messages
+        f, x, map(DI.unwrap, contexts)...; config
     )
     contexts_tup_false = map(_ -> false, contexts)
     args_to_zero = (
diff --git a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/twoarg.jl b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/twoarg.jl
index 2ee11b5ae..14b5c2503 100644
--- a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/twoarg.jl
+++ b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/twoarg.jl
@@ -27,8 +27,7 @@ function DI.prepare_pullback_nokwarg(
         y,
         x,
         map(DI.unwrap, contexts)...;
-        debug_mode = config.debug_mode,
-        silence_debug_messages = config.silence_debug_messages,
+        config,
     )
     dy_righttype_after = zero_tangent(y)
     contexts_tup_false = map(_ -> false, contexts)

From a62c5189b5cd3219ac5f88668d41792b01496de5 Mon Sep 17 00:00:00 2001
From: Guillaume Dalle <22795598+gdalle@users.noreply.github.com>
Date: Fri, 30 Jan 2026 10:34:39 +0100
Subject: [PATCH 2/9] Remove useless _righttype caches

---
 DifferentiationInterface/Project.toml         |  2 +-
 .../forward_onearg.jl                         | 14 ++++-----
 .../forward_twoarg.jl                         | 29 ++++++-------------
 .../onearg.jl                                 | 16 +++-------
 .../twoarg.jl                                 | 14 ++++-----
 .../utils.jl                                  |  2 +-
 .../test/Back/Mooncake/Project.toml           |  3 ++
 .../test/Back/Mooncake/test.jl                | 10 ++++---
 8 files changed, 36 insertions(+), 54 deletions(-)

diff --git a/DifferentiationInterface/Project.toml b/DifferentiationInterface/Project.toml
index f54fd1f4f..af16a6ae2 100644
--- a/DifferentiationInterface/Project.toml
+++ b/DifferentiationInterface/Project.toml
@@ -69,7 +69,7 @@ ForwardDiff = "0.10.36,1"
 GPUArraysCore = "0.2"
 GTPSA = "1.4.0"
 LinearAlgebra = "1"
-Mooncake = "0.5.0"
+Mooncake = "0.5.1"
 PolyesterForwardDiff = "0.1.2"
 ReverseDiff = "1.15.1"
 SparseArrays = "1"
diff --git a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_onearg.jl b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_onearg.jl
index b64549b89..5615cdbd7 100644
--- a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_onearg.jl
+++ b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_onearg.jl
@@ -1,9 +1,8 @@
 ## Pushforward
 
-struct MooncakeOneArgPushforwardPrep{SIG, Tcache, DX, FT, CT} <: DI.PushforwardPrep{SIG}
+struct MooncakeOneArgPushforwardPrep{SIG, Tcache, FT, CT} <: DI.PushforwardPrep{SIG}
     _sig::Val{SIG}
     cache::Tcache
-    dx_righttype::DX
     df::FT
     context_tangents::CT
 end
@@ -21,10 +20,9 @@ function DI.prepare_pushforward_nokwarg(
     cache = prepare_derivative_cache(
         f, x, map(DI.unwrap, contexts)...; config
     )
-    dx_righttype = zero_tangent(x)
     df = zero_tangent(f)
     context_tangents = map(zero_tangent_unwrap, contexts)
-    prep = MooncakeOneArgPushforwardPrep(_sig, cache, dx_righttype, df, context_tangents)
+    prep = MooncakeOneArgPushforwardPrep(_sig, cache, df, context_tangents)
     return prep
 end
 
@@ -38,13 +36,11 @@ function DI.value_and_pushforward(
     ) where {F, C, X}
     DI.check_prep(f, prep, backend, x, tx, contexts...)
     ys_and_ty = map(tx) do dx
-        dx_righttype =
-            dx isa tangent_type(X) ? dx : _copy_to_output!!(prep.dx_righttype, dx)
         y_dual = value_and_derivative!!(
             prep.cache,
-            Dual(f, prep.df),
-            Dual(x, dx_righttype),
-            map(Dual_unwrap, contexts, prep.context_tangents)...,
+            (f, prep.df),
+            (x, dx),
+            map(first_unwrap, contexts, prep.context_tangents)...,
         )
         y = primal(y_dual)
         dy = _copy_output(tangent(y_dual))
diff --git a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl
index dea6138bc..929be485f 100644
--- a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl
+++ b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl
@@ -1,10 +1,8 @@
 ## Pushforward
 
-struct MooncakeTwoArgPushforwardPrep{SIG, Tcache, DX, DY, FT, CT} <: DI.PushforwardPrep{SIG}
+struct MooncakeTwoArgPushforwardPrep{SIG, Tcache, FT, CT} <: DI.PushforwardPrep{SIG}
     _sig::Val{SIG}
     cache::Tcache
-    dx_righttype::DX
-    dy_righttype::DY
     df!::FT
     context_tangents::CT
 end
@@ -27,11 +25,9 @@ function DI.prepare_pushforward_nokwarg(
         map(DI.unwrap, contexts)...;
         config
     )
-    dx_righttype = zero_tangent(x)
-    dy_righttype = zero_tangent(y)
     df! = zero_tangent(f!)
     context_tangents = map(zero_tangent_unwrap, contexts)
-    prep = MooncakeTwoArgPushforwardPrep(_sig, cache, dx_righttype, dy_righttype, df!, context_tangents)
+    prep = MooncakeTwoArgPushforwardPrep(_sig, cache, df!, context_tangents)
     return prep
 end
 
@@ -46,15 +42,13 @@ function DI.value_and_pushforward(
     ) where {F, C, X}
     DI.check_prep(f!, y, prep, backend, x, tx, contexts...)
     ty = map(tx) do dx
-        dx_righttype =
-            dx isa tangent_type(X) ? dx : _copy_to_output!!(prep.dx_righttype, dx)
         y_dual = zero_dual(y)
         value_and_derivative!!(
             prep.cache,
-            Dual(f!, prep.df!),
+            (f!, prep.df!),
             y_dual,
-            Dual(x, dx_righttype),
-            map(Dual_unwrap, contexts, prep.context_tangents)...,
+            (x, dx),
+            map(first_unwrap, contexts, prep.context_tangents)...,
         )
         dy = _copy_output(tangent(y_dual))
         return dy
@@ -87,18 +81,13 @@ function DI.value_and_pushforward!(
     ) where {F, C, X, Y}
     DI.check_prep(f!, y, prep, backend, x, tx, contexts...)
     foreach(tx, ty) do dx, dy
-        dx_righttype =
-            dx isa tangent_type(X) ? dx : _copy_to_output!!(prep.dx_righttype, dx)
-        dy_righttype =
-            dy isa tangent_type(Y) ? dy : _copy_to_output!!(prep.dy_righttype, dy)
         value_and_derivative!!(
             prep.cache,
-            Dual(f!, prep.df!),
-            Dual(y, dy_righttype),
-            Dual(x, dx_righttype),
-            map(Dual_unwrap, contexts, prep.context_tangents)...,
+            (f!, prep.df!),
+            (y, dy),
+            (x, dx),
+            map(first_unwrap, contexts, prep.context_tangents)...,
         )
-        dy === dy_righttype || copyto!(dy, dy_righttype)
     end
     return y, ty
 end
diff --git a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/onearg.jl b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/onearg.jl
index e52a2a498..6131d9fe4 100644
--- a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/onearg.jl
+++ b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/onearg.jl
@@ -1,9 +1,8 @@
 ## Pullback
 
-struct MooncakeOneArgPullbackPrep{SIG, Tcache, DY, N} <: DI.PullbackPrep{SIG}
+struct MooncakeOneArgPullbackPrep{SIG, Tcache, N} <: DI.PullbackPrep{SIG}
     _sig::Val{SIG}
     cache::Tcache
-    dy_righttype::DY
     args_to_zero::NTuple{N, Bool}
 end
 
@@ -15,15 +14,13 @@ function DI.prepare_pullback_nokwarg(
     cache = prepare_pullback_cache(
         f, x, map(DI.unwrap, contexts)...; config
     )
-    y = f(x, map(DI.unwrap, contexts)...)
-    dy_righttype = zero_tangent(y)
     contexts_tup_false = map(_ -> false, contexts)
     args_to_zero = (
         false,  # f
         true,  # x
         contexts_tup_false...,
     )
-    prep = MooncakeOneArgPullbackPrep(_sig, cache, dy_righttype, args_to_zero)
+    prep = MooncakeOneArgPullbackPrep(_sig, cache, args_to_zero)
     return prep
 end
 
@@ -37,10 +34,8 @@ function DI.value_and_pullback(
     ) where {F, Y, C}
     DI.check_prep(f, prep, backend, x, ty, contexts...)
     dy = only(ty)
-    dy_righttype = dy isa tangent_type(Y) ? dy : _copy_to_output!!(prep.dy_righttype, dy)
     new_y, (_, new_dx) = value_and_pullback!!(
-        prep.cache, dy_righttype, f, x, map(DI.unwrap, contexts)...;
-        prep.args_to_zero
+        prep.cache, dy, f, x, map(DI.unwrap, contexts)...; prep.args_to_zero
     )
     return new_y, (_copy_output(new_dx),)
 end
@@ -55,11 +50,8 @@ function DI.value_and_pullback(
     ) where {F, Y, C}
     DI.check_prep(f, prep, backend, x, ty, contexts...)
     ys_and_tx = map(ty) do dy
-        dy_righttype =
-            dy isa tangent_type(Y) ? dy : _copy_to_output!!(prep.dy_righttype, dy)
         y, (_, new_dx) = value_and_pullback!!(
-            prep.cache, dy_righttype, f, x, map(DI.unwrap, contexts)...;
-            prep.args_to_zero
+            prep.cache, dy, f, x, map(DI.unwrap, contexts)...; prep.args_to_zero
         )
         y, _copy_output(new_dx)
     end
diff --git a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/twoarg.jl b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/twoarg.jl
index 14b5c2503..90ed26443 100644
--- a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/twoarg.jl
+++ b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/twoarg.jl
@@ -1,7 +1,7 @@
 struct MooncakeTwoArgPullbackPrep{SIG, Tcache, DY, F, N} <: DI.PullbackPrep{SIG}
     _sig::Val{SIG}
     cache::Tcache
-    dy_righttype::DY
+    dy_backup::DY
     target_function::F
     args_to_zero::NTuple{N, Bool}
 end
@@ -29,7 +29,7 @@ function DI.prepare_pullback_nokwarg(
         map(DI.unwrap, contexts)...;
         config,
     )
-    dy_righttype_after = zero_tangent(y)
+    dy_backup_after = zero_tangent(y)
     contexts_tup_false = map(_ -> false, contexts)
     args_to_zero = (
         false,  # target_function
@@ -39,7 +39,7 @@ function DI.prepare_pullback_nokwarg(
         contexts_tup_false...,
     )
     prep = MooncakeTwoArgPullbackPrep(
-        _sig, cache, dy_righttype_after, target_function, args_to_zero
+        _sig, cache, dy_backup_after, target_function, args_to_zero
     )
     return prep
 end
@@ -56,11 +56,11 @@ function DI.value_and_pullback(
     DI.check_prep(f!, y, prep, backend, x, ty, contexts...)
     dy = only(ty)
     # Prepare cotangent to add after the forward pass.
-    dy_righttype_after = copyto!(prep.dy_righttype, dy)
+    dy_backup_after = copyto!(prep.dy_backup, dy)
     # Run the reverse-pass and return the results.
     y_after, (_, _, _, dx) = value_and_pullback!!(
         prep.cache,
-        dy_righttype_after,
+        dy_backup_after,
         prep.target_function,
         f!,
         y,
@@ -83,10 +83,10 @@ function DI.value_and_pullback(
     ) where {F, C}
     DI.check_prep(f!, y, prep, backend, x, ty, contexts...)
     tx = map(ty) do dy
-        dy_righttype_after = copyto!(prep.dy_righttype, dy)
+        dy_backup_after = copyto!(prep.dy_backup, dy)
         y_after, (_, _, _, dx) = value_and_pullback!!(
             prep.cache,
-            dy_righttype_after,
+            dy_backup_after,
             prep.target_function,
             f!,
             y,
diff --git a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/utils.jl b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/utils.jl
index 56e4b966a..b56437d66 100644
--- a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/utils.jl
+++ b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/utils.jl
@@ -2,4 +2,4 @@ get_config(::AnyAutoMooncake{Nothing}) = Config()
 get_config(backend::AnyAutoMooncake{<:Config}) = backend.config
 
 @inline zero_tangent_unwrap(c::DI.Context) = zero_tangent(DI.unwrap(c))
-@inline Dual_unwrap(c, dc) = Dual(DI.unwrap(c), dc)
+@inline first_unwrap(c, dc) = (DI.unwrap(c), dc)
diff --git a/DifferentiationInterface/test/Back/Mooncake/Project.toml b/DifferentiationInterface/test/Back/Mooncake/Project.toml
index 39a878d7e..3fb318369 100644
--- a/DifferentiationInterface/test/Back/Mooncake/Project.toml
+++ b/DifferentiationInterface/test/Back/Mooncake/Project.toml
@@ -7,3 +7,6 @@ Mooncake = "da2b9cff-9c12-43a0-ae48-6db2b0edb7d6"
 SparseConnectivityTracer = "9f842d2f-2579-4b1d-911e-f412cf18a3f5"
 SparseMatrixColorings = "0a514795-09f3-496d-8182-132a7b665d35"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
+
+[sources]
+Mooncake = { url = "https://github.com/gdalle/Mooncake.jl", rev = "gd/forwardcache" }
diff --git a/DifferentiationInterface/test/Back/Mooncake/test.jl b/DifferentiationInterface/test/Back/Mooncake/test.jl
index f2d6add4c..55891e8a4 100644
--- a/DifferentiationInterface/test/Back/Mooncake/test.jl
+++ b/DifferentiationInterface/test/Back/Mooncake/test.jl
@@ -7,11 +7,11 @@ using Test
 using ExplicitImports
 check_no_implicit_imports(DifferentiationInterface)
 
-
 backends = [
-    AutoMooncake(; config = nothing),
-    AutoMooncake(; config = Mooncake.Config()),
-    AutoMooncakeForward(; config = nothing),
+    AutoMooncake(),
+    AutoMooncake(; config = Mooncake.Config(; friendly_tangents = true)),
+    AutoMooncakeForward(),
+    AutoMooncakeForward(; config = Mooncake.Config(; friendly_tangents = true)),
 ]
 
 for backend in backends
@@ -51,3 +51,5 @@ test_differentiation(
     @test grad.A == ps.B
     @test grad.B == ps.A
 end
+
+# TODO: test static arrays with friendly tangents!

From 4bf5dc674ce5f0eb92ddfe01e286c1ccaef74d48 Mon Sep 17 00:00:00 2001
From: Guillaume Dalle <22795598+gdalle@users.noreply.github.com>
Date: Fri, 30 Jan 2026 10:55:06 +0100
Subject: [PATCH 3/9] No dual output

---
 .../DifferentiationInterfaceMooncakeExt/forward_onearg.jl   | 6 +++---
 .../DifferentiationInterfaceMooncakeExt/forward_twoarg.jl   | 5 ++---
 2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_onearg.jl b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_onearg.jl
index 5615cdbd7..42bc8fb0a 100644
--- a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_onearg.jl
+++ b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_onearg.jl
@@ -36,14 +36,14 @@ function DI.value_and_pushforward(
     ) where {F, C, X}
     DI.check_prep(f, prep, backend, x, tx, contexts...)
     ys_and_ty = map(tx) do dx
-        y_dual = value_and_derivative!!(
+        y_and_dy = value_and_derivative!!(
             prep.cache,
             (f, prep.df),
             (x, dx),
             map(first_unwrap, contexts, prep.context_tangents)...,
         )
-        y = primal(y_dual)
-        dy = _copy_output(tangent(y_dual))
+        y = first(y_and_dy)
+        dy = _copy_output(last(y_and_dy))
         return y, dy
     end
     y = first(ys_and_ty[1])
diff --git a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl
index 929be485f..b3dff8380 100644
--- a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl
+++ b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl
@@ -42,15 +42,14 @@ function DI.value_and_pushforward(
     ) where {F, C, X}
     DI.check_prep(f!, y, prep, backend, x, tx, contexts...)
     ty = map(tx) do dx
-        y_dual = zero_dual(y)
+        dy = zero_tangent(y)  # TODO: remove allocation?
         value_and_derivative!!(
             prep.cache,
             (f!, prep.df!),
-            y_dual,
+            (y, dy),
             (x, dx),
             map(first_unwrap, contexts, prep.context_tangents)...,
         )
-        dy = _copy_output(tangent(y_dual))
         return dy
     end
     return y, ty

From 604bd8ec4d78f7269141c85f355d03ccf2a60b27 Mon Sep 17 00:00:00 2001
From: Guillaume Dalle <22795598+gdalle@users.noreply.github.com>
Date: Fri, 30 Jan 2026 16:30:23 +0100
Subject: [PATCH 4/9] Fixes

---
 .../forward_onearg.jl                           |  2 +-
 .../forward_twoarg.jl                           | 10 +++++++---
 .../twoarg.jl                                   | 17 ++++++-----------
 .../utils.jl                                    |  5 +++++
 .../test/Back/Mooncake/Project.toml             |  3 ---
 5 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_onearg.jl b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_onearg.jl
index 42bc8fb0a..dbcd8f7e0 100644
--- a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_onearg.jl
+++ b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_onearg.jl
@@ -46,7 +46,7 @@ function DI.value_and_pushforward(
         dy = _copy_output(last(y_and_dy))
         return y, dy
     end
-    y = first(ys_and_ty[1])
+    y = _copy_output(first(ys_and_ty[1]))
     ty = map(last, ys_and_ty)
     return y, ty
 end
diff --git a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl
index b3dff8380..4375d74cd 100644
--- a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl
+++ b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl
@@ -19,6 +19,7 @@ function DI.prepare_pushforward_nokwarg(
     _sig = DI.signature(f!, y, backend, x, tx, contexts...; strict)
     config = get_config(backend)
     cache = prepare_derivative_cache(
+        call_and_return,
         f!,
         y,
         x,
@@ -43,14 +44,15 @@ function DI.value_and_pushforward(
     DI.check_prep(f!, y, prep, backend, x, tx, contexts...)
     ty = map(tx) do dx
         dy = zero_tangent(y)  # TODO: remove allocation?
-        value_and_derivative!!(
+        _, new_dy = value_and_derivative!!(
             prep.cache,
+            (call_and_return, zero_tangent(call_and_return)),
             (f!, prep.df!),
             (y, dy),
             (x, dx),
             map(first_unwrap, contexts, prep.context_tangents)...,
         )
-        return dy
+        return _copy_output(new_dy)
     end
     return y, ty
 end
@@ -80,13 +82,15 @@ function DI.value_and_pushforward!(
     ) where {F, C, X, Y}
     DI.check_prep(f!, y, prep, backend, x, tx, contexts...)
     foreach(tx, ty) do dx, dy
-        value_and_derivative!!(
+        _, new_dy = value_and_derivative!!(
             prep.cache,
+            (call_and_return, zero_tangent(call_and_return)),
             (f!, prep.df!),
             (y, dy),
             (x, dx),
             map(first_unwrap, contexts, prep.context_tangents)...,
         )
+        copyto!(dy, new_dy)
     end
     return y, ty
 end
diff --git a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/twoarg.jl b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/twoarg.jl
index 90ed26443..e29fe92e9 100644
--- a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/twoarg.jl
+++ b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/twoarg.jl
@@ -1,8 +1,7 @@
-struct MooncakeTwoArgPullbackPrep{SIG, Tcache, DY, F, N} <: DI.PullbackPrep{SIG}
+struct MooncakeTwoArgPullbackPrep{SIG, Tcache, DY, N} <: DI.PullbackPrep{SIG}
     _sig::Val{SIG}
     cache::Tcache
     dy_backup::DY
-    target_function::F
     args_to_zero::NTuple{N, Bool}
 end
 
@@ -16,13 +15,9 @@ function DI.prepare_pullback_nokwarg(
         contexts::Vararg{DI.Context, C}
     ) where {F, C}
     _sig = DI.signature(f!, y, backend, x, ty, contexts...; strict)
-    target_function = function (f!, y, x, contexts...)
-        f!(y, x, contexts...)
-        return y
-    end
     config = get_config(backend)
     cache = prepare_pullback_cache(
-        target_function,
+        call_and_return,
         f!,
         y,
         x,
@@ -32,14 +27,14 @@ function DI.prepare_pullback_nokwarg(
     dy_backup_after = zero_tangent(y)
     contexts_tup_false = map(_ -> false, contexts)
     args_to_zero = (
-        false,  # target_function
+        false,  # call_and_return
         false,  # f!
         false,  # y
         true,  # x
         contexts_tup_false...,
     )
     prep = MooncakeTwoArgPullbackPrep(
-        _sig, cache, dy_backup_after, target_function, args_to_zero
+        _sig, cache, dy_backup_after, args_to_zero
     )
     return prep
 end
@@ -61,7 +56,7 @@ function DI.value_and_pullback(
     y_after, (_, _, _, dx) = value_and_pullback!!(
         prep.cache,
         dy_backup_after,
-        prep.target_function,
+        call_and_return,
         f!,
         y,
         x,
@@ -87,7 +82,7 @@ function DI.value_and_pullback(
         y_after, (_, _, _, dx) = value_and_pullback!!(
             prep.cache,
             dy_backup_after,
-            prep.target_function,
+            call_and_return,
             f!,
             y,
             x,
diff --git a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/utils.jl b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/utils.jl
index b56437d66..5c4c0cf87 100644
--- a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/utils.jl
+++ b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/utils.jl
@@ -3,3 +3,8 @@ get_config(backend::AnyAutoMooncake{<:Config}) = backend.config
 
 @inline zero_tangent_unwrap(c::DI.Context) = zero_tangent(DI.unwrap(c))
 @inline first_unwrap(c, dc) = (DI.unwrap(c), dc)
+
+function call_and_return(f!::F, y, x, contexts...) where {F}
+    f!(y, x, contexts...)
+    return y
+end
diff --git a/DifferentiationInterface/test/Back/Mooncake/Project.toml b/DifferentiationInterface/test/Back/Mooncake/Project.toml
index 3fb318369..39a878d7e 100644
--- a/DifferentiationInterface/test/Back/Mooncake/Project.toml
+++ b/DifferentiationInterface/test/Back/Mooncake/Project.toml
@@ -7,6 +7,3 @@ Mooncake = "da2b9cff-9c12-43a0-ae48-6db2b0edb7d6"
 SparseConnectivityTracer = "9f842d2f-2579-4b1d-911e-f412cf18a3f5"
 SparseMatrixColorings = "0a514795-09f3-496d-8182-132a7b665d35"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
-
-[sources]
-Mooncake = { url = "https://github.com/gdalle/Mooncake.jl", rev = "gd/forwardcache" }

From aa9c806440e55d19525462d6845339a84a16ef77 Mon Sep 17 00:00:00 2001
From: Guillaume Dalle <22795598+gdalle@users.noreply.github.com>
Date: Sat, 31 Jan 2026 10:40:29 +0100
Subject: [PATCH 5/9] Fix and test friendly tangents with static arrays

---
 .../DifferentiationInterfaceMooncakeExt.jl         |  3 ++-
 .../forward_onearg.jl                              |  6 ++----
 .../forward_twoarg.jl                              | 10 ++++++----
 .../DifferentiationInterfaceMooncakeExt/onearg.jl  |  8 ++------
 .../DifferentiationInterfaceMooncakeExt/twoarg.jl  | 12 ++++++------
 .../DifferentiationInterfaceMooncakeExt/utils.jl   |  9 +++++++++
 .../test/Back/Mooncake/Project.toml                |  1 +
 .../test/Back/Mooncake/test.jl                     | 14 ++++++++++----
 8 files changed, 38 insertions(+), 25 deletions(-)

diff --git a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/DifferentiationInterfaceMooncakeExt.jl b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/DifferentiationInterfaceMooncakeExt.jl
index 561c06cc8..3513d548c 100644
--- a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/DifferentiationInterfaceMooncakeExt.jl
+++ b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/DifferentiationInterfaceMooncakeExt.jl
@@ -29,7 +29,8 @@ using Mooncake:
     NoRData,
     primal,
     _copy_output,
-    _copy_to_output!!
+    _copy_to_output!!,
+    tangent_to_primal!!
 
 const AnyAutoMooncake{C} = Union{AutoMooncake{C}, AutoMooncakeForward{C}}
 
diff --git a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_onearg.jl b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_onearg.jl
index dbcd8f7e0..c470b6473 100644
--- a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_onearg.jl
+++ b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_onearg.jl
@@ -17,10 +17,8 @@ function DI.prepare_pushforward_nokwarg(
     ) where {F, C}
     _sig = DI.signature(f, backend, x, tx, contexts...; strict)
     config = get_config(backend)
-    cache = prepare_derivative_cache(
-        f, x, map(DI.unwrap, contexts)...; config
-    )
-    df = zero_tangent(f)
+    cache = prepare_derivative_cache(f, x, map(DI.unwrap, contexts)...; config)
+    df = zero_tangent_or_primal(f, backend)
     context_tangents = map(zero_tangent_unwrap, contexts)
     prep = MooncakeOneArgPushforwardPrep(_sig, cache, df, context_tangents)
     return prep
diff --git a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl
index 4375d74cd..20033a659 100644
--- a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl
+++ b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl
@@ -26,7 +26,7 @@ function DI.prepare_pushforward_nokwarg(
         map(DI.unwrap, contexts)...;
         config
     )
-    df! = zero_tangent(f!)
+    df! = zero_tangent_or_primal(f!, backend)
     context_tangents = map(zero_tangent_unwrap, contexts)
     prep = MooncakeTwoArgPushforwardPrep(_sig, cache, df!, context_tangents)
     return prep
@@ -43,10 +43,11 @@ function DI.value_and_pushforward(
     ) where {F, C, X}
     DI.check_prep(f!, y, prep, backend, x, tx, contexts...)
     ty = map(tx) do dx
-        dy = zero_tangent(y)  # TODO: remove allocation?
+        dy = zero_tangent_or_primal(y, backend)  # TODO: remove allocation?
+        dcall = zero_tangent_or_primal(call_and_return, backend)
         _, new_dy = value_and_derivative!!(
             prep.cache,
-            (call_and_return, zero_tangent(call_and_return)),
+            (call_and_return, dcall),
             (f!, prep.df!),
             (y, dy),
             (x, dx),
@@ -82,9 +83,10 @@ function DI.value_and_pushforward!(
     ) where {F, C, X, Y}
     DI.check_prep(f!, y, prep, backend, x, tx, contexts...)
     foreach(tx, ty) do dx, dy
+        dcall = zero_tangent_or_primal(call_and_return, backend)
         _, new_dy = value_and_derivative!!(
             prep.cache,
-            (call_and_return, zero_tangent(call_and_return)),
+            (call_and_return, dcall),
             (f!, prep.df!),
             (y, dy),
             (x, dx),
diff --git a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/onearg.jl b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/onearg.jl
index 6131d9fe4..2514cdc40 100644
--- a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/onearg.jl
+++ b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/onearg.jl
@@ -11,9 +11,7 @@ function DI.prepare_pullback_nokwarg(
     ) where {F, C}
     _sig = DI.signature(f, backend, x, ty, contexts...; strict)
     config = get_config(backend)
-    cache = prepare_pullback_cache(
-        f, x, map(DI.unwrap, contexts)...; config
-    )
+    cache = prepare_pullback_cache(f, x, map(DI.unwrap, contexts)...; config)
     contexts_tup_false = map(_ -> false, contexts)
     args_to_zero = (
         false,  # f
@@ -113,9 +111,7 @@ function DI.prepare_gradient_nokwarg(
     ) where {F, C}
     _sig = DI.signature(f, backend, x, contexts...; strict)
     config = get_config(backend)
-    cache = prepare_gradient_cache(
-        f, x, map(DI.unwrap, contexts)...; config
-    )
+    cache = prepare_gradient_cache(f, x, map(DI.unwrap, contexts)...; config)
     contexts_tup_false = map(_ -> false, contexts)
     args_to_zero = (
         false,  # f
diff --git a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/twoarg.jl b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/twoarg.jl
index e29fe92e9..2b55131b9 100644
--- a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/twoarg.jl
+++ b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/twoarg.jl
@@ -24,7 +24,7 @@ function DI.prepare_pullback_nokwarg(
         map(DI.unwrap, contexts)...;
         config,
     )
-    dy_backup_after = zero_tangent(y)
+    dy_backup = zero_tangent_or_primal(y, backend)
     contexts_tup_false = map(_ -> false, contexts)
     args_to_zero = (
         false,  # call_and_return
@@ -34,7 +34,7 @@ function DI.prepare_pullback_nokwarg(
         contexts_tup_false...,
     )
     prep = MooncakeTwoArgPullbackPrep(
-        _sig, cache, dy_backup_after, args_to_zero
+        _sig, cache, dy_backup, args_to_zero
     )
     return prep
 end
@@ -51,11 +51,11 @@ function DI.value_and_pullback(
     DI.check_prep(f!, y, prep, backend, x, ty, contexts...)
     dy = only(ty)
     # Prepare cotangent to add after the forward pass.
-    dy_backup_after = copyto!(prep.dy_backup, dy)
+    dy_backup = copyto!(prep.dy_backup, dy)
     # Run the reverse-pass and return the results.
     y_after, (_, _, _, dx) = value_and_pullback!!(
         prep.cache,
-        dy_backup_after,
+        dy_backup,
         call_and_return,
         f!,
         y,
@@ -78,10 +78,10 @@ function DI.value_and_pullback(
     ) where {F, C}
     DI.check_prep(f!, y, prep, backend, x, ty, contexts...)
     tx = map(ty) do dy
-        dy_backup_after = copyto!(prep.dy_backup, dy)
+        dy_backup = copyto!(prep.dy_backup, dy)
         y_after, (_, _, _, dx) = value_and_pullback!!(
             prep.cache,
-            dy_backup_after,
+            dy_backup,
             call_and_return,
             f!,
             y,
diff --git a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/utils.jl b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/utils.jl
index 5c4c0cf87..8f6437b49 100644
--- a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/utils.jl
+++ b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/utils.jl
@@ -8,3 +8,12 @@ function call_and_return(f!::F, y, x, contexts...) where {F}
     f!(y, x, contexts...)
     return y
 end
+
+function zero_tangent_or_primal(x, backend::AnyAutoMooncake)
+    if backend.config.friendly_tangents
+        # zero(x) but safer
+        return tangent_to_primal!!(_copy_output(x), zero_tangent(x))
+    else
+        return zero_tangent(x)
+    end
+end
diff --git a/DifferentiationInterface/test/Back/Mooncake/Project.toml b/DifferentiationInterface/test/Back/Mooncake/Project.toml
index 39a878d7e..f13f37c5b 100644
--- a/DifferentiationInterface/test/Back/Mooncake/Project.toml
+++ b/DifferentiationInterface/test/Back/Mooncake/Project.toml
@@ -6,4 +6,5 @@ ExplicitImports = "7d51a73a-1435-4ff3-83d9-f097790105c7"
 Mooncake = "da2b9cff-9c12-43a0-ae48-6db2b0edb7d6"
 SparseConnectivityTracer = "9f842d2f-2579-4b1d-911e-f412cf18a3f5"
 SparseMatrixColorings = "0a514795-09f3-496d-8182-132a7b665d35"
+StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
diff --git a/DifferentiationInterface/test/Back/Mooncake/test.jl b/DifferentiationInterface/test/Back/Mooncake/test.jl
index 55891e8a4..7748a316b 100644
--- a/DifferentiationInterface/test/Back/Mooncake/test.jl
+++ b/DifferentiationInterface/test/Back/Mooncake/test.jl
@@ -9,8 +9,8 @@ check_no_implicit_imports(DifferentiationInterface)
 
 backends = [
     AutoMooncake(),
-    AutoMooncake(; config = Mooncake.Config(; friendly_tangents = true)),
     AutoMooncakeForward(),
+    AutoMooncake(; config = Mooncake.Config(; friendly_tangents = true)),
     AutoMooncakeForward(; config = Mooncake.Config(; friendly_tangents = true)),
 ]
 
@@ -22,7 +22,8 @@ end
 test_differentiation(
     backends,
     default_scenarios(;
-        include_constantified = true, include_cachified = true, use_tuples = true
+        include_batchified = false,
+        include_constantified = false, include_cachified = false, use_tuples = true
     );
     excluded = SECOND_ORDER,
     logging = LOGGING,
@@ -39,7 +40,7 @@ end
 
 # Test second-order differentiation (forward-over-reverse)
 test_differentiation(
-    [SecondOrder(AutoMooncakeForward(; config = nothing), AutoMooncake(; config = nothing))],
+    [SecondOrder(AutoMooncakeForward(), AutoMooncake())],
     excluded = EXCLUDED,
     logging = true,
 )
@@ -52,4 +53,9 @@ test_differentiation(
     @test grad.B == ps.A
 end
 
-# TODO: test static arrays with friendly tangents!
+test_differentiation(
+    backends[3:4],
+    static_scenarios();
+    logging = LOGGING,
+    excluded = SECOND_ORDER
+)

From 0b13cda1c41b11a82b87d6189c788ee17f0d3a4a Mon Sep 17 00:00:00 2001
From: Guillaume Dalle <22795598+gdalle@users.noreply.github.com>
Date: Sat, 31 Jan 2026 11:01:35 +0100
Subject: [PATCH 6/9] Fix config

---
 .github/workflows/Test.yml                    | 276 +++++++++---------
 .../utils.jl                                  |   2 +-
 2 files changed, 139 insertions(+), 139 deletions(-)

diff --git a/.github/workflows/Test.yml b/.github/workflows/Test.yml
index 69ecf753e..52689f618 100644
--- a/.github/workflows/Test.yml
+++ b/.github/workflows/Test.yml
@@ -16,71 +16,71 @@ concurrency:
   cancel-in-progress: ${{ startsWith(github.ref, 'refs/pull/') }}
 
 jobs:
-  test-DI-Core:
-    name: ${{ matrix.version }} - DI Core (${{ matrix.group }})
-    runs-on: ubuntu-latest
-    if: ${{ !contains(github.event.pull_request.labels.*.name, 'skipci') }}
-    timeout-minutes: 120
-    permissions: # needed to allow julia-actions/cache to proactively delete old caches that it has created
-      actions: write
-      contents: read
-    strategy:
-      fail-fast: false # TODO: toggle
-      matrix:
-        version:
-          - '1.10'
-          - '1.11'
-          - '1.12'
-        group:
-          - Internals
-          - SimpleFiniteDiff
-          - ZeroBackends
-        skip_lts:
-          - ${{ github.event.pull_request.draft }}
-        skip_pre:
-          - ${{ github.event.pull_request.draft }}
-        exclude:
-          - skip_lts: true
-            version: '1.10'
-          - skip_pre: true
-            version: '1.12'
-    env:
-      JULIA_DI_TEST_TYPE: 'Core'
-      JULIA_DI_TEST_GROUP: ${{ matrix.group }}
-      JULIA_DI_PR_DRAFT: ${{ github.event.pull_request.draft }}
-    steps:
-      - uses: actions/checkout@v6
-      - uses: julia-actions/setup-julia@v2
-        with:
-          version: ${{ matrix.version }}
-          arch: x64
-      - uses: julia-actions/cache@v2
-      - name: Install dependencies & run tests
-        run: julia --color=yes -e '
-          using Pkg;
-          Pkg.activate("./DifferentiationInterface/test");
-          if VERSION < v"1.11";
-          Pkg.rm("DifferentiationInterfaceTest");
-          Pkg.resolve();
-          else;
-          Pkg.develop(; path="./DifferentiationInterfaceTest");
-          end;
-          Pkg.activate("./DifferentiationInterface");
-          test_kwargs = (; allow_reresolve=false, coverage=true);
-          if ENV["JULIA_DI_PR_DRAFT"] == "true";
-          Pkg.test("DifferentiationInterface"; julia_args=["-O1"], test_kwargs...);
-          else;
-          Pkg.test("DifferentiationInterface"; test_kwargs...);
-          end;'
-      - uses: julia-actions/julia-processcoverage@v1
-        with:
-          directories: ./DifferentiationInterface/src,./DifferentiationInterface/ext,./DifferentiationInterface/test
-      - uses: codecov/codecov-action@v5
-        with:
-          files: lcov.info
-          flags: DI
-          token: ${{ secrets.CODECOV_TOKEN }}
-          fail_ci_if_error: false
+  # test-DI-Core:
+  #   name: ${{ matrix.version }} - DI Core (${{ matrix.group }})
+  #   runs-on: ubuntu-latest
+  #   if: ${{ !contains(github.event.pull_request.labels.*.name, 'skipci') }}
+  #   timeout-minutes: 120
+  #   permissions: # needed to allow julia-actions/cache to proactively delete old caches that it has created
+  #     actions: write
+  #     contents: read
+  #   strategy:
+  #     fail-fast: false # TODO: toggle
+  #     matrix:
+  #       version:
+  #         - '1.10'
+  #         - '1.11'
+  #         - '1.12'
+  #       group:
+  #         - Internals
+  #         - SimpleFiniteDiff
+  #         - ZeroBackends
+  #       skip_lts:
+  #         - ${{ github.event.pull_request.draft }}
+  #       skip_pre:
+  #         - ${{ github.event.pull_request.draft }}
+  #       exclude:
+  #         - skip_lts: true
+  #           version: '1.10'
+  #         - skip_pre: true
+  #           version: '1.12'
+  #   env:
+  #     JULIA_DI_TEST_TYPE: 'Core'
+  #     JULIA_DI_TEST_GROUP: ${{ matrix.group }}
+  #     JULIA_DI_PR_DRAFT: ${{ github.event.pull_request.draft }}
+  #   steps:
+  #     - uses: actions/checkout@v6
+  #     - uses: julia-actions/setup-julia@v2
+  #       with:
+  #         version: ${{ matrix.version }}
+  #         arch: x64
+  #     - uses: julia-actions/cache@v2
+  #     - name: Install dependencies & run tests
+  #       run: julia --color=yes -e '
+  #         using Pkg;
+  #         Pkg.activate("./DifferentiationInterface/test");
+  #         if VERSION < v"1.11";
+  #         Pkg.rm("DifferentiationInterfaceTest");
+  #         Pkg.resolve();
+  #         else;
+  #         Pkg.develop(; path="./DifferentiationInterfaceTest");
+  #         end;
+  #         Pkg.activate("./DifferentiationInterface");
+  #         test_kwargs = (; allow_reresolve=false, coverage=true);
+  #         if ENV["JULIA_DI_PR_DRAFT"] == "true";
+  #         Pkg.test("DifferentiationInterface"; julia_args=["-O1"], test_kwargs...);
+  #         else;
+  #         Pkg.test("DifferentiationInterface"; test_kwargs...);
+  #         end;'
+  #     - uses: julia-actions/julia-processcoverage@v1
+  #       with:
+  #         directories: ./DifferentiationInterface/src,./DifferentiationInterface/ext,./DifferentiationInterface/test
+  #     - uses: codecov/codecov-action@v5
+  #       with:
+  #         files: lcov.info
+  #         flags: DI
+  #         token: ${{ secrets.CODECOV_TOKEN }}
+  #         fail_ci_if_error: false
 
   test-DI-Backend:
     name: ${{ matrix.version }} - DI Back (${{ matrix.group }})
@@ -98,22 +98,22 @@ jobs:
           - '1.11'
           - '1.12'
         group:
-          - ChainRules
-          - DifferentiateWith
-          # - Diffractor
-          - Enzyme
-          - FastDifferentiation
-          - FiniteDiff
-          - FiniteDifferences
-          - ForwardDiff
-          - GTPSA
+          # - ChainRules
+          # - DifferentiateWith
+          # # - Diffractor
+          # - Enzyme
+          # - FastDifferentiation
+          # - FiniteDiff
+          # - FiniteDifferences
+          # - ForwardDiff
+          # - GTPSA
           - Mooncake
-          - PolyesterForwardDiff
-          - ReverseDiff
-          - SparsityDetector
-          - Symbolics
-          - Tracker
-          - Zygote
+          # - PolyesterForwardDiff
+          # - ReverseDiff
+          # - SparsityDetector
+          # - Symbolics
+          # - Tracker
+          # - Zygote
         skip_lts:
           - ${{ github.event.pull_request.draft }}
         skip_pre:
@@ -157,61 +157,61 @@ jobs:
           token: ${{ secrets.CODECOV_TOKEN }}
           fail_ci_if_error: false
 
-  test-DIT:
-    name: ${{ matrix.version }} - DIT (${{ matrix.group }})
-    runs-on: ubuntu-latest
-    if: ${{ !contains(github.event.pull_request.labels.*.name, 'skipci') }}
-    timeout-minutes: 60
-    permissions: # needed to allow julia-actions/cache to proactively delete old caches that it has created
-      actions: write
-      contents: read
-    strategy:
-      fail-fast: false # TODO: toggle
-      matrix:
-        version:
-          - '1.10'
-          - '1.11'
-          - '1.12'
-        group:
-          - Formalities
-          - Zero
-          - Standard
-          - Weird
-        skip_lts:
-          - ${{ github.event.pull_request.draft }}
-        skip_pre:
-          - ${{ github.event.pull_request.draft }}
-        exclude:
-          - skip_lts: true
-            version: '1.10'
-          - skip_pre: true
-            version: '1.12'
-    env:
-      JULIA_DIT_TEST_GROUP: ${{ matrix.group }}
-      JULIA_DI_PR_DRAFT: ${{ github.event.pull_request.draft }}
-    steps:
-      - uses: actions/checkout@v6
-      - uses: julia-actions/setup-julia@v2
-        with:
-          version: ${{ matrix.version }}
-          arch: x64
-      - uses: julia-actions/cache@v2
-      - name: Install dependencies & run tests
-        run: julia --project=./DifferentiationInterfaceTest --color=yes -e '
-          using Pkg;
-          Pkg.Registry.update();
-          Pkg.develop(path="./DifferentiationInterface");
-          if ENV["JULIA_DI_PR_DRAFT"] == "true";
-          Pkg.test("DifferentiationInterfaceTest"; allow_reresolve=false, coverage=true, julia_args=["-O1"]);
-          else;
-          Pkg.test("DifferentiationInterfaceTest"; allow_reresolve=false, coverage=true);
-          end;'
-      - uses: julia-actions/julia-processcoverage@v1
-        with:
-          directories: ./DifferentiationInterfaceTest/src,./DifferentiationInterfaceTest/ext,./DifferentiationInterfaceTest/test
-      - uses: codecov/codecov-action@v5
-        with:
-          files: lcov.info
-          flags: DIT
-          token: ${{ secrets.CODECOV_TOKEN }}
-          fail_ci_if_error: false
+  # test-DIT:
+  #   name: ${{ matrix.version }} - DIT (${{ matrix.group }})
+  #   runs-on: ubuntu-latest
+  #   if: ${{ !contains(github.event.pull_request.labels.*.name, 'skipci') }}
+  #   timeout-minutes: 60
+  #   permissions: # needed to allow julia-actions/cache to proactively delete old caches that it has created
+  #     actions: write
+  #     contents: read
+  #   strategy:
+  #     fail-fast: false # TODO: toggle
+  #     matrix:
+  #       version:
+  #         - '1.10'
+  #         - '1.11'
+  #         - '1.12'
+  #       group:
+  #         - Formalities
+  #         - Zero
+  #         - Standard
+  #         - Weird
+  #       skip_lts:
+  #         - ${{ github.event.pull_request.draft }}
+  #       skip_pre:
+  #         - ${{ github.event.pull_request.draft }}
+  #       exclude:
+  #         - skip_lts: true
+  #           version: '1.10'
+  #         - skip_pre: true
+  #           version: '1.12'
+  #   env:
+  #     JULIA_DIT_TEST_GROUP: ${{ matrix.group }}
+  #     JULIA_DI_PR_DRAFT: ${{ github.event.pull_request.draft }}
+  #   steps:
+  #     - uses: actions/checkout@v6
+  #     - uses: julia-actions/setup-julia@v2
+  #       with:
+  #         version: ${{ matrix.version }}
+  #         arch: x64
+  #     - uses: julia-actions/cache@v2
+  #     - name: Install dependencies & run tests
+  #       run: julia --project=./DifferentiationInterfaceTest --color=yes -e '
+  #         using Pkg;
+  #         Pkg.Registry.update();
+  #         Pkg.develop(path="./DifferentiationInterface");
+  #         if ENV["JULIA_DI_PR_DRAFT"] == "true";
+  #         Pkg.test("DifferentiationInterfaceTest"; allow_reresolve=false, coverage=true, julia_args=["-O1"]);
+  #         else;
+  #         Pkg.test("DifferentiationInterfaceTest"; allow_reresolve=false, coverage=true);
+  #         end;'
+  #     - uses: julia-actions/julia-processcoverage@v1
+  #       with:
+  #         directories: ./DifferentiationInterfaceTest/src,./DifferentiationInterfaceTest/ext,./DifferentiationInterfaceTest/test
+  #     - uses: codecov/codecov-action@v5
+  #       with:
+  #         files: lcov.info
+  #         flags: DIT
+  #         token: ${{ secrets.CODECOV_TOKEN }}
+  #         fail_ci_if_error: false
diff --git a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/utils.jl b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/utils.jl
index 8f6437b49..b22d8d49b 100644
--- a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/utils.jl
+++ b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/utils.jl
@@ -10,7 +10,7 @@ function call_and_return(f!::F, y, x, contexts...) where {F}
 end
 
 function zero_tangent_or_primal(x, backend::AnyAutoMooncake)
-    if backend.config.friendly_tangents
+    if get_config(backend).friendly_tangents
         # zero(x) but safer
         return tangent_to_primal!!(_copy_output(x), zero_tangent(x))
     else

From ed3de268c919a384fac371fb0731f54ac77064d3 Mon Sep 17 00:00:00 2001
From: Guillaume Dalle <22795598+gdalle@users.noreply.github.com>
Date: Sat, 31 Jan 2026 11:05:08 +0100
Subject: [PATCH 7/9] No logging

---
 DifferentiationInterface/test/Back/Mooncake/test.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/DifferentiationInterface/test/Back/Mooncake/test.jl b/DifferentiationInterface/test/Back/Mooncake/test.jl
index 7748a316b..6156b3aec 100644
--- a/DifferentiationInterface/test/Back/Mooncake/test.jl
+++ b/DifferentiationInterface/test/Back/Mooncake/test.jl
@@ -42,7 +42,7 @@ end
 test_differentiation(
     [SecondOrder(AutoMooncakeForward(), AutoMooncake())],
     excluded = EXCLUDED,
-    logging = true,
+    logging = LOGGING,
 )
 
 @testset "NamedTuples" begin

From 00b7f09ad7fed89502985e4fb4c63a399bcfb741 Mon Sep 17 00:00:00 2001
From: Guillaume Dalle <22795598+gdalle@users.noreply.github.com>
Date: Sat, 31 Jan 2026 11:54:45 +0100
Subject: [PATCH 8/9] Reactivate other tests

---
 .github/workflows/Test.yml | 276 ++++++++++++++++++-------------------
 1 file changed, 138 insertions(+), 138 deletions(-)

diff --git a/.github/workflows/Test.yml b/.github/workflows/Test.yml
index 52689f618..69ecf753e 100644
--- a/.github/workflows/Test.yml
+++ b/.github/workflows/Test.yml
@@ -16,71 +16,71 @@ concurrency:
   cancel-in-progress: ${{ startsWith(github.ref, 'refs/pull/') }}
 
 jobs:
-  # test-DI-Core:
-  #   name: ${{ matrix.version }} - DI Core (${{ matrix.group }})
-  #   runs-on: ubuntu-latest
-  #   if: ${{ !contains(github.event.pull_request.labels.*.name, 'skipci') }}
-  #   timeout-minutes: 120
-  #   permissions: # needed to allow julia-actions/cache to proactively delete old caches that it has created
-  #     actions: write
-  #     contents: read
-  #   strategy:
-  #     fail-fast: false # TODO: toggle
-  #     matrix:
-  #       version:
-  #         - '1.10'
-  #         - '1.11'
-  #         - '1.12'
-  #       group:
-  #         - Internals
-  #         - SimpleFiniteDiff
-  #         - ZeroBackends
-  #       skip_lts:
-  #         - ${{ github.event.pull_request.draft }}
-  #       skip_pre:
-  #         - ${{ github.event.pull_request.draft }}
-  #       exclude:
-  #         - skip_lts: true
-  #           version: '1.10'
-  #         - skip_pre: true
-  #           version: '1.12'
-  #   env:
-  #     JULIA_DI_TEST_TYPE: 'Core'
-  #     JULIA_DI_TEST_GROUP: ${{ matrix.group }}
-  #     JULIA_DI_PR_DRAFT: ${{ github.event.pull_request.draft }}
-  #   steps:
-  #     - uses: actions/checkout@v6
-  #     - uses: julia-actions/setup-julia@v2
-  #       with:
-  #         version: ${{ matrix.version }}
-  #         arch: x64
-  #     - uses: julia-actions/cache@v2
-  #     - name: Install dependencies & run tests
-  #       run: julia --color=yes -e '
-  #         using Pkg;
-  #         Pkg.activate("./DifferentiationInterface/test");
-  #         if VERSION < v"1.11";
-  #         Pkg.rm("DifferentiationInterfaceTest");
-  #         Pkg.resolve();
-  #         else;
-  #         Pkg.develop(; path="./DifferentiationInterfaceTest");
-  #         end;
-  #         Pkg.activate("./DifferentiationInterface");
-  #         test_kwargs = (; allow_reresolve=false, coverage=true);
-  #         if ENV["JULIA_DI_PR_DRAFT"] == "true";
-  #         Pkg.test("DifferentiationInterface"; julia_args=["-O1"], test_kwargs...);
-  #         else;
-  #         Pkg.test("DifferentiationInterface"; test_kwargs...);
-  #         end;'
-  #     - uses: julia-actions/julia-processcoverage@v1
-  #       with:
-  #         directories: ./DifferentiationInterface/src,./DifferentiationInterface/ext,./DifferentiationInterface/test
-  #     - uses: codecov/codecov-action@v5
-  #       with:
-  #         files: lcov.info
-  #         flags: DI
-  #         token: ${{ secrets.CODECOV_TOKEN }}
-  #         fail_ci_if_error: false
+  test-DI-Core:
+    name: ${{ matrix.version }} - DI Core (${{ matrix.group }})
+    runs-on: ubuntu-latest
+    if: ${{ !contains(github.event.pull_request.labels.*.name, 'skipci') }}
+    timeout-minutes: 120
+    permissions: # needed to allow julia-actions/cache to proactively delete old caches that it has created
+      actions: write
+      contents: read
+    strategy:
+      fail-fast: false # TODO: toggle
+      matrix:
+        version:
+          - '1.10'
+          - '1.11'
+          - '1.12'
+        group:
+          - Internals
+          - SimpleFiniteDiff
+          - ZeroBackends
+        skip_lts:
+          - ${{ github.event.pull_request.draft }}
+        skip_pre:
+          - ${{ github.event.pull_request.draft }}
+        exclude:
+          - skip_lts: true
+            version: '1.10'
+          - skip_pre: true
+            version: '1.12'
+    env:
+      JULIA_DI_TEST_TYPE: 'Core'
+      JULIA_DI_TEST_GROUP: ${{ matrix.group }}
+      JULIA_DI_PR_DRAFT: ${{ github.event.pull_request.draft }}
+    steps:
+      - uses: actions/checkout@v6
+      - uses: julia-actions/setup-julia@v2
+        with:
+          version: ${{ matrix.version }}
+          arch: x64
+      - uses: julia-actions/cache@v2
+      - name: Install dependencies & run tests
+        run: julia --color=yes -e '
+          using Pkg;
+          Pkg.activate("./DifferentiationInterface/test");
+          if VERSION < v"1.11";
+          Pkg.rm("DifferentiationInterfaceTest");
+          Pkg.resolve();
+          else;
+          Pkg.develop(; path="./DifferentiationInterfaceTest");
+          end;
+          Pkg.activate("./DifferentiationInterface");
+          test_kwargs = (; allow_reresolve=false, coverage=true);
+          if ENV["JULIA_DI_PR_DRAFT"] == "true";
+          Pkg.test("DifferentiationInterface"; julia_args=["-O1"], test_kwargs...);
+          else;
+          Pkg.test("DifferentiationInterface"; test_kwargs...);
+          end;'
+      - uses: julia-actions/julia-processcoverage@v1
+        with:
+          directories: ./DifferentiationInterface/src,./DifferentiationInterface/ext,./DifferentiationInterface/test
+      - uses: codecov/codecov-action@v5
+        with:
+          files: lcov.info
+          flags: DI
+          token: ${{ secrets.CODECOV_TOKEN }}
+          fail_ci_if_error: false
 
   test-DI-Backend:
     name: ${{ matrix.version }} - DI Back (${{ matrix.group }})
@@ -98,22 +98,22 @@ jobs:
           - '1.11'
           - '1.12'
         group:
-          # - ChainRules
-          # - DifferentiateWith
-          # # - Diffractor
-          # - Enzyme
-          # - FastDifferentiation
-          # - FiniteDiff
-          # - FiniteDifferences
-          # - ForwardDiff
-          # - GTPSA
+          - ChainRules
+          - DifferentiateWith
+          # - Diffractor
+          - Enzyme
+          - FastDifferentiation
+          - FiniteDiff
+          - FiniteDifferences
+          - ForwardDiff
+          - GTPSA
           - Mooncake
-          # - PolyesterForwardDiff
-          # - ReverseDiff
-          # - SparsityDetector
-          # - Symbolics
-          # - Tracker
-          # - Zygote
+          - PolyesterForwardDiff
+          - ReverseDiff
+          - SparsityDetector
+          - Symbolics
+          - Tracker
+          - Zygote
         skip_lts:
           - ${{ github.event.pull_request.draft }}
         skip_pre:
@@ -157,61 +157,61 @@ jobs:
           token: ${{ secrets.CODECOV_TOKEN }}
           fail_ci_if_error: false
 
-  # test-DIT:
-  #   name: ${{ matrix.version }} - DIT (${{ matrix.group }})
-  #   runs-on: ubuntu-latest
-  #   if: ${{ !contains(github.event.pull_request.labels.*.name, 'skipci') }}
-  #   timeout-minutes: 60
-  #   permissions: # needed to allow julia-actions/cache to proactively delete old caches that it has created
-  #     actions: write
-  #     contents: read
-  #   strategy:
-  #     fail-fast: false # TODO: toggle
-  #     matrix:
-  #       version:
-  #         - '1.10'
-  #         - '1.11'
-  #         - '1.12'
-  #       group:
-  #         - Formalities
-  #         - Zero
-  #         - Standard
-  #         - Weird
-  #       skip_lts:
-  #         - ${{ github.event.pull_request.draft }}
-  #       skip_pre:
-  #         - ${{ github.event.pull_request.draft }}
-  #       exclude:
-  #         - skip_lts: true
-  #           version: '1.10'
-  #         - skip_pre: true
-  #           version: '1.12'
-  #   env:
-  #     JULIA_DIT_TEST_GROUP: ${{ matrix.group }}
-  #     JULIA_DI_PR_DRAFT: ${{ github.event.pull_request.draft }}
-  #   steps:
-  #     - uses: actions/checkout@v6
-  #     - uses: julia-actions/setup-julia@v2
-  #       with:
-  #         version: ${{ matrix.version }}
-  #         arch: x64
-  #     - uses: julia-actions/cache@v2
-  #     - name: Install dependencies & run tests
-  #       run: julia --project=./DifferentiationInterfaceTest --color=yes -e '
-  #         using Pkg;
-  #         Pkg.Registry.update();
-  #         Pkg.develop(path="./DifferentiationInterface");
-  #         if ENV["JULIA_DI_PR_DRAFT"] == "true";
-  #         Pkg.test("DifferentiationInterfaceTest"; allow_reresolve=false, coverage=true, julia_args=["-O1"]);
-  #         else;
-  #         Pkg.test("DifferentiationInterfaceTest"; allow_reresolve=false, coverage=true);
-  #         end;'
-  #     - uses: julia-actions/julia-processcoverage@v1
-  #       with:
-  #         directories: ./DifferentiationInterfaceTest/src,./DifferentiationInterfaceTest/ext,./DifferentiationInterfaceTest/test
-  #     - uses: codecov/codecov-action@v5
-  #       with:
-  #         files: lcov.info
-  #         flags: DIT
-  #         token: ${{ secrets.CODECOV_TOKEN }}
-  #         fail_ci_if_error: false
+  test-DIT:
+    name: ${{ matrix.version }} - DIT (${{ matrix.group }})
+    runs-on: ubuntu-latest
+    if: ${{ !contains(github.event.pull_request.labels.*.name, 'skipci') }}
+    timeout-minutes: 60
+    permissions: # needed to allow julia-actions/cache to proactively delete old caches that it has created
+      actions: write
+      contents: read
+    strategy:
+      fail-fast: false # TODO: toggle
+      matrix:
+        version:
+          - '1.10'
+          - '1.11'
+          - '1.12'
+        group:
+          - Formalities
+          - Zero
+          - Standard
+          - Weird
+        skip_lts:
+          - ${{ github.event.pull_request.draft }}
+        skip_pre:
+          - ${{ github.event.pull_request.draft }}
+        exclude:
+          - skip_lts: true
+            version: '1.10'
+          - skip_pre: true
+            version: '1.12'
+    env:
+      JULIA_DIT_TEST_GROUP: ${{ matrix.group }}
+      JULIA_DI_PR_DRAFT: ${{ github.event.pull_request.draft }}
+    steps:
+      - uses: actions/checkout@v6
+      - uses: julia-actions/setup-julia@v2
+        with:
+          version: ${{ matrix.version }}
+          arch: x64
+      - uses: julia-actions/cache@v2
+      - name: Install dependencies & run tests
+        run: julia --project=./DifferentiationInterfaceTest --color=yes -e '
+          using Pkg;
+          Pkg.Registry.update();
+          Pkg.develop(path="./DifferentiationInterface");
+          if ENV["JULIA_DI_PR_DRAFT"] == "true";
+          Pkg.test("DifferentiationInterfaceTest"; allow_reresolve=false, coverage=true, julia_args=["-O1"]);
+          else;
+          Pkg.test("DifferentiationInterfaceTest"; allow_reresolve=false, coverage=true);
+          end;'
+      - uses: julia-actions/julia-processcoverage@v1
+        with:
+          directories: ./DifferentiationInterfaceTest/src,./DifferentiationInterfaceTest/ext,./DifferentiationInterfaceTest/test
+      - uses: codecov/codecov-action@v5
+        with:
+          files: lcov.info
+          flags: DIT
+          token: ${{ secrets.CODECOV_TOKEN }}
+          fail_ci_if_error: false

From 6639952594a70db85c708a580099ed727f4f8782 Mon Sep 17 00:00:00 2001
From: Guillaume Dalle <22795598+gdalle@users.noreply.github.com>
Date: Sat, 31 Jan 2026 19:24:48 +0100
Subject: [PATCH 9/9] Retoggle tests

---
 .../forward_twoarg.jl                           | 17 +++++++++--------
 .../test/Back/Mooncake/test.jl                  |  3 +--
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl
index 20033a659..3c75f530b 100644
--- a/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl
+++ b/DifferentiationInterface/ext/DifferentiationInterfaceMooncakeExt/forward_twoarg.jl
@@ -1,9 +1,11 @@
 ## Pushforward
 
-struct MooncakeTwoArgPushforwardPrep{SIG, Tcache, FT, CT} <: DI.PushforwardPrep{SIG}
+struct MooncakeTwoArgPushforwardPrep{SIG, Tcache, FT0, FT, YT, CT} <: DI.PushforwardPrep{SIG}
     _sig::Val{SIG}
     cache::Tcache
+    dcall::FT0
     df!::FT
+    dy::YT
     context_tangents::CT
 end
 
@@ -26,9 +28,11 @@ function DI.prepare_pushforward_nokwarg(
         map(DI.unwrap, contexts)...;
         config
     )
+    dcall = zero_tangent_or_primal(call_and_return, backend)
     df! = zero_tangent_or_primal(f!, backend)
+    dy = zero_tangent_or_primal(y, backend)
     context_tangents = map(zero_tangent_unwrap, contexts)
-    prep = MooncakeTwoArgPushforwardPrep(_sig, cache, df!, context_tangents)
+    prep = MooncakeTwoArgPushforwardPrep(_sig, cache, dcall, df!, dy, context_tangents)
     return prep
 end
 
@@ -43,13 +47,11 @@ function DI.value_and_pushforward(
     ) where {F, C, X}
     DI.check_prep(f!, y, prep, backend, x, tx, contexts...)
     ty = map(tx) do dx
-        dy = zero_tangent_or_primal(y, backend)  # TODO: remove allocation?
-        dcall = zero_tangent_or_primal(call_and_return, backend)
         _, new_dy = value_and_derivative!!(
             prep.cache,
-            (call_and_return, dcall),
+            (call_and_return, prep.dcall),
             (f!, prep.df!),
-            (y, dy),
+            (y, prep.dy),
             (x, dx),
             map(first_unwrap, contexts, prep.context_tangents)...,
         )
@@ -83,10 +85,9 @@ function DI.value_and_pushforward!(
     ) where {F, C, X, Y}
     DI.check_prep(f!, y, prep, backend, x, tx, contexts...)
     foreach(tx, ty) do dx, dy
-        dcall = zero_tangent_or_primal(call_and_return, backend)
         _, new_dy = value_and_derivative!!(
             prep.cache,
-            (call_and_return, dcall),
+            (call_and_return, prep.dcall),
             (f!, prep.df!),
             (y, dy),
             (x, dx),
diff --git a/DifferentiationInterface/test/Back/Mooncake/test.jl b/DifferentiationInterface/test/Back/Mooncake/test.jl
index 6156b3aec..8c67aa1bb 100644
--- a/DifferentiationInterface/test/Back/Mooncake/test.jl
+++ b/DifferentiationInterface/test/Back/Mooncake/test.jl
@@ -22,8 +22,7 @@ end
 test_differentiation(
     backends,
     default_scenarios(;
-        include_batchified = false,
-        include_constantified = false, include_cachified = false, use_tuples = true
+        include_constantified = true, include_cachified = true, use_tuples = true
     );
     excluded = SECOND_ORDER,
     logging = LOGGING,