From 29456a009c26ec721e273bfd3f846c853c0b2526 Mon Sep 17 00:00:00 2001
From: Aayush Sabharwal <aayush.sabharwal@gmail.com>
Date: Mon, 17 Nov 2025 11:55:34 +0530
Subject: [PATCH 1/2] feat: update to Symbolics@7

---
 Project.toml                          |  2 +-
 ext/DataInterpolationsSymbolicsExt.jl | 41 +++++++++++++++++++++------
 2 files changed, 33 insertions(+), 10 deletions(-)

diff --git a/Project.toml b/Project.toml
index 7f38079d..efaea1d5 100644
--- a/Project.toml
+++ b/Project.toml
@@ -51,7 +51,7 @@ SafeTestsets = "0.1"
 SparseConnectivityTracer = "1"
 StableRNGs = "1"
 StaticArrays = "1.9"
-Symbolics = "6.46"
+Symbolics = "6.46, 7"
 Test = "1.10"
 Unitful = "1.21.1"
 Zygote = "0.6.77, 0.7"
diff --git a/ext/DataInterpolationsSymbolicsExt.jl b/ext/DataInterpolationsSymbolicsExt.jl
index 317856b7..04e91a68 100644
--- a/ext/DataInterpolationsSymbolicsExt.jl
+++ b/ext/DataInterpolationsSymbolicsExt.jl
@@ -8,17 +8,40 @@ using Symbolics: Num, unwrap, SymbolicUtils
 @register_symbolic (interp::AbstractInterpolation)(t)
 Base.nameof(interp::AbstractInterpolation) = :Interpolation
 
-function derivative(interp::AbstractInterpolation, t::Num, order = 1)
-    Symbolics.wrap(SymbolicUtils.term(derivative, interp, unwrap(t), order))
-end
-SymbolicUtils.promote_symtype(::typeof(derivative), _...) = Real
+@static if pkgversion(Symbolics) >= v"7"
+    @register_symbolic derivative(interp::AbstractInterpolation, t, order::Integer) false
+    function SymbolicUtils.promote_symtype(::typeof(derivative), Ti::SymbolicUtils.TypeT,
+            Tt::SymbolicUtils.TypeT,
+            To::SymbolicUtils.TypeT)
+        @assert Ti <: AbstractInterpolation
+        @assert Tt <: Real
+        @assert To <: Integer
+        Real
+    end
+    function SymbolicUtils.promote_shape(::typeof(derivative),
+            @nospecialize(shi::SymbolicUtils.ShapeT),
+            @nospecialize(sht::SymbolicUtils.ShapeT),
+            @nospecialize(sho::SymbolicUtils.ShapeT))
+        @assert !SymbolicUtils.is_array_shape(shi)
+        @assert !SymbolicUtils.is_array_shape(sht)
+        @assert !SymbolicUtils.is_array_shape(sho)
+        return SymbolicUtils.ShapeVecT()
+    end
 
-function Symbolics.derivative(::typeof(derivative), args::NTuple{3, Any}, ::Val{2})
-    Symbolics.unwrap(derivative(args[1], Symbolics.wrap(args[2]), args[3] + 1))
-end
+    @register_derivative derivative(interp, t, ord) 2 derivative(interp, t, ord + 1)
+    @register_derivative (interp::AbstractInterpolation)(t) 1 derivative(interp, t, 1)
+else
+    function derivative(interp::AbstractInterpolation, t::Num, order = 1)
+        Symbolics.wrap(SymbolicUtils.term(derivative, interp, unwrap(t), order))
+    end
+    SymbolicUtils.promote_symtype(::typeof(derivative), _...) = Real
+    function Symbolics.derivative(::typeof(derivative), args::NTuple{3, Any}, ::Val{2})
+        Symbolics.unwrap(derivative(args[1], Symbolics.wrap(args[2]), args[3] + 1))
+    end
 
-function Symbolics.derivative(interp::AbstractInterpolation, args::NTuple{1, Any}, ::Val{1})
-    Symbolics.unwrap(derivative(interp, Symbolics.wrap(args[1])))
+    function Symbolics.derivative(interp::AbstractInterpolation, args::NTuple{1, Any}, ::Val{1})
+        Symbolics.unwrap(derivative(interp, Symbolics.wrap(args[1])))
+    end
 end
 
 end # module

From 0e9903bb3fdd68f06ff4b1bcad162c42a4a0f79f Mon Sep 17 00:00:00 2001
From: Aayush Sabharwal <aayush.sabharwal@gmail.com>
Date: Mon, 17 Nov 2025 12:16:21 +0530
Subject: [PATCH 2/2] test: update tests to Symbolics@7

---
 test/derivative_tests.jl | 4 ++--
 test/interface.jl        | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/test/derivative_tests.jl b/test/derivative_tests.jl
index 9b35bf89..a5257ce7 100644
--- a/test/derivative_tests.jl
+++ b/test/derivative_tests.jl
@@ -335,8 +335,8 @@ end
     expr = A(ω)
     @test isequal(Symbolics.derivative(expr, τ), D(ω) * DataInterpolations.derivative(A, ω))
 
-    derivexpr1 = expand_derivatives(substitute(D(A(ω)), Dict(ω => 0.5τ)))
-    derivexpr2 = expand_derivatives(substitute(D2(A(ω)), Dict(ω => 0.5τ)))
+    derivexpr1 = expand_derivatives(substitute(D(A(ω)), Dict(ω => 0.5τ); filterer = Returns(true)))
+    derivexpr2 = expand_derivatives(substitute(D2(A(ω)), Dict(ω => 0.5τ); filterer = Returns(true)))
     symfunc1 = Symbolics.build_function(derivexpr1, τ; expression = Val{false})
     symfunc2 = Symbolics.build_function(derivexpr2, τ; expression = Val{false})
     @test symfunc1(0.5) == 1.5
diff --git a/test/interface.jl b/test/interface.jl
index f7222f5b..fa8f635b 100644
--- a/test/interface.jl
+++ b/test/interface.jl
@@ -23,9 +23,9 @@ end
     @variables t x(t)
     substitute(A(t), Dict(t => x))
     t_val = 2.7
-    @test substitute(A(t), Dict(t => t_val)) == A(t_val)
-    @test substitute(B(A(t)), Dict(t => t_val)) == B(A(t_val))
-    @test substitute(A(B(A(t))), Dict(t => t_val)) == A(B(A(t_val)))
+    @test substitute(A(t), Dict(t => t_val); fold = Val(true)) == A(t_val)
+    @test substitute(B(A(t)), Dict(t => t_val); fold = Val(true)) == B(A(t_val))
+    @test substitute(A(B(A(t))), Dict(t => t_val); fold = Val(true)) == A(B(A(t_val)))
 end
 
 @testset "Type Inference" begin