From 9afe916a6635e2427e3e789faff5fb5801d0c04c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9s=20Riedemann?=
 <38795484+longemen3000@users.noreply.github.com>
Date: Tue, 13 May 2025 22:38:37 -0400
Subject: [PATCH 1/2] use `oneunit(T)` in `construct_seeds`

---
 Project.toml     | 3 ++-
 src/dual.jl      | 3 +++
 src/partials.jl  | 2 +-
 test/MiscTest.jl | 5 +++++
 4 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/Project.toml b/Project.toml
index e43900af..14bd787b 100644
--- a/Project.toml
+++ b/Project.toml
@@ -40,9 +40,10 @@ Calculus = "49dc2e85-a5d0-5ad3-a950-438e2897f1b9"
 DiffTests = "de460e47-3fe3-5279-bb4a-814414816d5d"
 InteractiveUtils = "b77e0a4c-d291-57a0-90e8-8db25a27a240"
 IrrationalConstants = "92d709cd-6900-40b7-9082-c6be49f344b6"
+Measurements = "eff96d63-e80a-5855-80a2-b1b0885c5ab7"
 SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
 StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [targets]
-test = ["Calculus", "DiffTests", "IrrationalConstants", "SparseArrays", "StaticArrays", "Test", "InteractiveUtils"]
+test = ["Calculus", "DiffTests", "IrrationalConstants", "Measurements", "SparseArrays", "StaticArrays", "Test", "InteractiveUtils"]
diff --git a/src/dual.jl b/src/dual.jl
index 7e8ec110..6a3c9344 100644
--- a/src/dual.jl
+++ b/src/dual.jl
@@ -359,6 +359,9 @@ end
 @inline Base.one(d::Dual) = one(typeof(d))
 @inline Base.one(::Type{Dual{T,V,N}}) where {T,V,N} = Dual{T}(one(V), zero(Partials{N,V}))
 
+@inline Base.oneunit(d::Dual{T}) where {T} = Dual{T}(oneunit(value(d)), zero(partials(d)))
+@inline Base.oneunit(::Type{Dual{T,V,N}}) where {T,V,N} = Dual{T}(oneunit(V), zero(Partials{N,V}))
+
 @inline function Base.Int(d::Dual)
     all(iszero, partials(d)) || throw(InexactError(:Int, Int, d))
     Int(value(d))
diff --git a/src/partials.jl b/src/partials.jl
index a5316e3e..ddec4ebc 100644
--- a/src/partials.jl
+++ b/src/partials.jl
@@ -7,7 +7,7 @@ end
 ##############################
 
 @generated function single_seed(::Type{Partials{N,V}}, ::Val{i}) where {N,V,i}
-    ex = Expr(:tuple, [ifelse(i === j, :(one(V)), :(zero(V))) for j in 1:N]...)
+    ex = Expr(:tuple, [ifelse(i === j, :(oneunit(V)), :(zero(V))) for j in 1:N]...)
     return :(Partials($(ex)))
 end
 
diff --git a/test/MiscTest.jl b/test/MiscTest.jl
index e7e0d91a..df26a8cc 100644
--- a/test/MiscTest.jl
+++ b/test/MiscTest.jl
@@ -9,6 +9,7 @@ using SparseArrays: sparse
 using StaticArrays
 using IrrationalConstants
 using LinearAlgebra
+using Measurements: Measurements
 
 include(joinpath(dirname(@__FILE__), "utils.jl"))
 
@@ -219,4 +220,8 @@ end
     @test B_mmatrix == B
 end
 
+#issue 651, using Measurements
+f651(x) = 2.1*x + 1
+@test ForwardDiff.derivative(f651,Measurements.measurement(1.0, 0.001)) == 2.1
+
 end # module

From 13ceac8bb2ba047fc2efb209c577ac1cbcba66f8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9s=20Riedemann?=
 <38795484+longemen3000@users.noreply.github.com>
Date: Tue, 13 May 2025 22:59:59 -0400
Subject: [PATCH 2/2] remove test_broken that now pass

---
 test/AllocationsTest.jl | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/test/AllocationsTest.jl b/test/AllocationsTest.jl
index ad1832d0..42f694c3 100644
--- a/test/AllocationsTest.jl
+++ b/test/AllocationsTest.jl
@@ -33,11 +33,7 @@ convert_test_574() = convert(ForwardDiff.Dual{Nothing,ForwardDiff.Dual{Nothing,F
     index = 1
     alloc = @allocated ForwardDiff.seed!(duals, x, index, seed)
     alloc = @allocated ForwardDiff.seed!(duals, x, index, seed)
-    if VERSION < v"1.9" || VERSION >= v"1.11"
-        @test alloc == 0
-    else
-        @test_broken alloc == 0
-    end
+    @test alloc == 0
 
     alloc = @allocated convert_test_574()
     alloc = @allocated convert_test_574()