Fix @static_unpack and add JET type stability tests

- Fix _maybe_SArray functions in static_arrays.jl to properly construct SVector
  and SArray types by including element type parameter and using Tuple(x)
  conversion for type stability
- Add JET.jl as test dependency
- Add JET type stability tests for core ComponentArray operations
- The @static_unpack macro now correctly returns SVector and SMatrix types

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: claude

src/compat/static_arrays.jl

@@ -3,11 +3,15 @@ function ComponentArray{A}(::UndefInitializer, ax::Axes) where {
     return ComponentArray(similar(A), ax...)
 end
 
-_maybe_SArray(x::SubArray, ::Val{N}, ::FlatAxis) where {N} = SVector{N}(x)
-function _maybe_SArray(x::Base.ReshapedArray, ::Val, ::ShapedAxis{Sz}) where {Sz}
-    SArray{Tuple{Sz...}}(x)
+function _maybe_SArray(x::SubArray{T}, ::Val{N}, ::FlatAxis) where {T, N}
+    SVector{N, T}(Tuple(x))
+end
+function _maybe_SArray(x::Base.ReshapedArray{T, N}, ::Val, ::ShapedAxis{Sz}) where {T, N, Sz}
+    SArray{Tuple{Sz...}, T, N, prod(Sz)}(Tuple(x))
+end
+function _maybe_SArray(x::AbstractArray{T}, ::Val, ::Shaped1DAxis{Sz}) where {T, Sz}
+    SVector{Sz[1], T}(Tuple(x))
 end
-_maybe_SArray(x, ::Val, ::Shaped1DAxis{Sz}) where {Sz} = SArray{Tuple{Sz...}}(x)
 _maybe_SArray(x, vals...) = x
 
 @generated function static_getproperty(ca::ComponentVector, ::Val{s}) where {s}

test/Project.toml

@@ -7,6 +7,7 @@ FiniteDiff = "6a86dc24-6348-571c-b903-95158fe2bd41"
 ForwardDiff = "f6369f11-7733-5829-9624-2563aa707210"
 Functors = "d9f16b24-f501-4c13-a1f2-28368ffc5196"
 InvertedIndices = "41ab1584-1d38-5bbf-9106-f11c6c58b48f"
+JET = "c3a54625-cd67-489e-a8e7-0a5a0ff4e31b"
 JLArrays = "27aeb0d3-9eb9-45fb-866b-73c2ecf80fcb"
 LabelledArrays = "2ee39098-c373-598a-b85f-a56591580800"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"

test/jet_tests.jl

@@ -0,0 +1,31 @@
+using JET
+using ComponentArrays
+using Test
+
+@testset "JET type stability" begin
+    # Test key ComponentArray operations for type stability
+    ca = ComponentArray(a = 1.0, b = [2.0, 3.0], c = (d = 4.0, e = [5.0, 6.0]))
+
+    @testset "Core operations" begin
+        # Test getdata type stability
+        report = JET.report_opt(ComponentArrays.getdata, (typeof(ca),))
+        @test length(JET.get_reports(report)) == 0
+
+        # Test getaxes type stability
+        report = JET.report_opt(ComponentArrays.getaxes, (typeof(ca),))
+        @test length(JET.get_reports(report)) == 0
+
+        # Test numeric indexing type stability
+        report = JET.report_opt(getindex, (typeof(ca), Int))
+        @test length(JET.get_reports(report)) == 0
+    end
+
+    @testset "Construction" begin
+        # Test ComponentArray construction from NamedTuple
+        nt = (a = 1.0, b = [2.0, 3.0])
+        report = JET.report_opt(ComponentArray, (typeof(nt),))
+        # Note: some reports may come from Base, we only check ComponentArrays
+        ca_reports = filter(r -> occursin("ComponentArrays", string(r)), JET.get_reports(report))
+        @test length(ca_reports) == 0
+    end
+end

test/runtests.jl

@@ -982,3 +982,7 @@ end
 @testset "Reactant" begin
     include("reactant_tests.jl")
 end
+
+@testset "JET" begin
+    include("jet_tests.jl")
+end