From 2779f31f36d045e977d1c061d71ce6ac9890877c Mon Sep 17 00:00:00 2001
From: qwjyh <urataw421@gmail.com>
Date: Sun, 25 Jan 2026 20:20:09 +0900
Subject: [PATCH] feat: add extension for FixedSizeArrays (collect_structarray
 initializer)

---
 Project.toml                          | 12 ++++++++----
 ext/StructArraysFixedSizeArraysExt.jl | 28 +++++++++++++++++++++++++++
 test/runtests.jl                      | 13 +++++++++++++
 3 files changed, 49 insertions(+), 4 deletions(-)
 create mode 100644 ext/StructArraysFixedSizeArraysExt.jl

diff --git a/Project.toml b/Project.toml
index 20a95ed..089b913 100644
--- a/Project.toml
+++ b/Project.toml
@@ -9,9 +9,10 @@ Tables = "bd369af6-aec1-5ad0-b16a-f7cc5008161c"
 
 [weakdeps]
 Adapt = "79e6a3ab-5dfb-504d-930d-738a2a938a0e"
+FixedSizeArrays = "3821ddf9-e5b5-40d5-8e25-6813ab96b5e2"
 GPUArraysCore = "46192b85-c4d5-4398-a991-12ede77f4527"
-LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 KernelAbstractions = "63c18a36-062a-441e-b654-da1e3ab1ce7c"
+LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
 StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 
@@ -21,6 +22,7 @@ StructArraysGPUArraysCoreExt = ["GPUArraysCore", "KernelAbstractions"]
 StructArraysLinearAlgebraExt = "LinearAlgebra"
 StructArraysSparseArraysExt = "SparseArrays"
 StructArraysStaticArraysExt = "StaticArrays"
+StructArraysFixedSizeArraysExt = "FixedSizeArrays"
 
 [compat]
 Adapt = "4"
@@ -28,11 +30,12 @@ Aqua = "0.8"
 ConstructionBase = "1"
 DataAPI = "1"
 Documenter = "1"
+FixedSizeArrays = "1.2.0"
 GPUArraysCore = "0.2"
 InfiniteArrays = "0.15"
 JLArrays = "0.2"
-LinearAlgebra = "1"
 KernelAbstractions = "0.9"
+LinearAlgebra = "1"
 OffsetArrays = "1"
 PooledArrays = "1"
 SparseArrays = "1"
@@ -47,11 +50,12 @@ julia = "1.10"
 Adapt = "79e6a3ab-5dfb-504d-930d-738a2a938a0e"
 Aqua = "4c88cf16-eb10-579e-8560-4a9242c79595"
 Documenter = "e30172f5-a6a5-5a46-863b-614d45cd2de4"
+FixedSizeArrays = "3821ddf9-e5b5-40d5-8e25-6813ab96b5e2"
 GPUArraysCore = "46192b85-c4d5-4398-a991-12ede77f4527"
 InfiniteArrays = "4858937d-0d70-526a-a4dd-2d5cb5dd786c"
 JLArrays = "27aeb0d3-9eb9-45fb-866b-73c2ecf80fcb"
-LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 KernelAbstractions = "63c18a36-062a-441e-b654-da1e3ab1ce7c"
+LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 OffsetArrays = "6fe1bfb0-de20-5000-8ca7-80f57d26f881"
 PooledArrays = "2dfb63ee-cc39-5dd5-95bd-886bf059d720"
 SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
@@ -61,4 +65,4 @@ TypedTables = "9d95f2ec-7b3d-5a63-8d20-e2491e220bb9"
 WeakRefStrings = "ea10d353-3f73-51f8-a26c-33c1cb351aa5"
 
 [targets]
-test = ["Adapt", "Aqua", "Documenter", "GPUArraysCore", "InfiniteArrays", "JLArrays", "LinearAlgebra", "KernelAbstractions", "OffsetArrays", "PooledArrays", "SparseArrays", "StaticArrays", "Test", "TypedTables", "WeakRefStrings"]
+test = ["Adapt", "Aqua", "Documenter", "FixedSizeArrays", "GPUArraysCore", "InfiniteArrays", "JLArrays", "LinearAlgebra", "KernelAbstractions", "OffsetArrays", "PooledArrays", "SparseArrays", "StaticArrays", "Test", "TypedTables", "WeakRefStrings"]
diff --git a/ext/StructArraysFixedSizeArraysExt.jl b/ext/StructArraysFixedSizeArraysExt.jl
new file mode 100644
index 0000000..25257a5
--- /dev/null
+++ b/ext/StructArraysFixedSizeArraysExt.jl
@@ -0,0 +1,28 @@
+module StructArraysFixedSizeArraysExt
+
+using StructArrays
+using FixedSizeArrays: FixedSizeArrayDefault
+
+export fixed_size_array_backed_initializer
+
+fixed_size_array_of(::Type{S}, d::NTuple{N, Any}) where {S, N} = similar(FixedSizeArrayDefault{S, N}, d)
+
+const fixed_size_array_backed_initializer = StructArrays.StructArrayInitializer(StructArrays.alwaysfalse, fixed_size_array_of)
+
+# Make `fixed_size_array_backed_initializer` available in `StructArrays` using this hack
+# https://github.com/itsdfish/PackageExtensionsExample.jl/blob/41581ab0371cf512ace5dd063f7e7935effbb256/ext/DistributionsExt.jl#L28
+function __init__()
+    Threads.@spawn begin
+        sleep(0.01)
+        Core.eval(
+            StructArrays,
+            quote
+                ext = Base.get_extension(StructArrays, :StructArraysFixedSizeArraysExt)
+                using .ext
+                VERSION >= v"1.11.0-DEV.469" && eval(Meta.parse("public fixed_size_array_backed_initializer"))
+            end
+        )
+    end
+end
+
+end
diff --git a/test/runtests.jl b/test/runtests.jl
index 4484283..deed5f0 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -11,6 +11,7 @@ using LinearAlgebra
 using Test
 using SparseArrays
 using InfiniteArrays
+using FixedSizeArrays
 
 import Aqua
 import KernelAbstractions as KA
@@ -1605,6 +1606,18 @@ end
     end
 end
 
+@testset "FixedSizeArray" begin
+    itr = (ComplexF64(x, x) for x in 1:10)
+    a = collect_structarray(
+        itr;
+        initializer = StructArrays.fixed_size_array_backed_initializer,
+    )
+    @test a isa StructArray
+    @test a.re isa FixedSizeArray
+    b = collect_structarray(itr)
+    @test all(a .== b)
+end
+
 @testset "project quality" begin
     Aqua.test_all(StructArrays)
 end