From 45ca432675f3193628acce4219451b232befcfd6 Mon Sep 17 00:00:00 2001
From: lkdvos <ldevos98@gmail.com>
Date: Wed, 10 Jun 2026 10:46:16 -0400
Subject: [PATCH] add support for Bumper.ResizeBuffer

---
 ext/TensorOperationsBumperExt.jl |  6 +++++-
 test/butensor.jl                 | 15 +++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/ext/TensorOperationsBumperExt.jl b/ext/TensorOperationsBumperExt.jl
index d710e06b..12791765 100644
--- a/ext/TensorOperationsBumperExt.jl
+++ b/ext/TensorOperationsBumperExt.jl
@@ -3,7 +3,11 @@ module TensorOperationsBumperExt
 using TensorOperations
 using Bumper
 
-const BumperBuffer = Union{SlabBuffer, AllocBuffer}
+const BumperBuffer = @static if isdefined(Bumper, :ResizeBuffer)
+    Union{SlabBuffer, AllocBuffer, Bumper.ResizeBuffer}
+else
+    Union{SlabBuffer, AllocBuffer}
+end
 
 function TensorOperations.tensoralloc(
         ::Type{A}, structure, ::Val{istemp}, buf::BumperBuffer
diff --git a/test/butensor.jl b/test/butensor.jl
index 55074d36..fefcb211 100644
--- a/test/butensor.jl
+++ b/test/butensor.jl
@@ -78,4 +78,19 @@ using Bumper
     @test E5 isa T
     @test HRAA5 ≈ HRAA1
     @test E5 ≈ E1
+
+    # resizebuffer (Bumper >= 0.7.2)
+    @static if isdefined(Bumper, :ResizeBuffer)
+        resizebuf = Bumper.ResizeBuffer()
+        @no_escape resizebuf @tensor allocator = resizebuf begin
+            HRAA6[a, s1, s2, c] := ρₗ[a, a'] * A1[a', t1, b] * A2[b, t2, c'] * ρᵣ[c', c] *
+                H[s1, s2, t1, t2]
+            E6 = ρₗ[a', a] * A1[a, s, b] * A2[b, s', c] * ρᵣ[c, c'] * H[t, t', s, s'] *
+                conj(A1[a', t, b']) * conj(A2[b', t', c'])
+        end
+        @test HRAA6 isa Array{T, 4}
+        @test E6 isa T
+        @test HRAA6 ≈ HRAA1
+        @test E6 ≈ E1
+    end
 end