From 9aa57065b2e5dca040e5093bdd17653044acaca7 Mon Sep 17 00:00:00 2001
From: Oscar Dowson <o.dowson@gmail.com>
Date: Fri, 17 Oct 2025 12:26:42 +1300
Subject: [PATCH 1/3] Fix serialization of BenchmarkGroup with JSON@1

---
 src/serialization.jl       | 14 ++++++++++++++
 test/SerializationTests.jl |  7 +++++++
 2 files changed, 21 insertions(+)

diff --git a/src/serialization.jl b/src/serialization.jl
index 5aa7cced..c4d7145a 100644
--- a/src/serialization.jl
+++ b/src/serialization.jl
@@ -29,6 +29,20 @@ function JSON.lower(x::Union{values(SUPPORTED_TYPES)...})
     return [string(nameof(typeof(x))), d]
 end
 
+# Special support is needed for JSON@1, because it doesn't know how to support
+# NTuple{N,String} as a dictionary key.
+#
+# Upstream issue: https://github.com/JuliaIO/JSON.jl/issues/399
+#
+# This method may be removed if the upstream issue is fixed.
+function JSON.lower(x::BenchmarkGroup)
+    d = Dict{String,Any}(
+        "data" => Dict(string(k) => v for (k, v) in x.data),
+        "tags" => x.tags,
+    )
+    return ["BenchmarkGroup", d]
+end
+
 # a minimal 'eval' function, mirroring KeyTypes, but being slightly more lenient
 safeeval(@nospecialize x) = x
 safeeval(x::QuoteNode) = x.value
diff --git a/test/SerializationTests.jl b/test/SerializationTests.jl
index e24314a1..3d4ab165 100644
--- a/test/SerializationTests.jl
+++ b/test/SerializationTests.jl
@@ -124,4 +124,11 @@ end
     @test BenchmarkTools.load(json_io) == [params]
 end
 
+@testset "issue_400_tuple_as_dict_key" begin
+    grp = BenchmarkTools.BenchmarkGroup()
+    grp["a", "b"] = BenchmarkTools.BenchmarkGroup()
+    contents = sprint(io -> BenchmarkTools.save(io, grp))
+    @test occursin(""""data":{"(\\\"a\\", \\"b\\")":[""", contents)
+end
+
 end # module

From 09333f1a770acdb0b71e86aa30b102bb0eec49fe Mon Sep 17 00:00:00 2001
From: Valentin Churavy <v.churavy@gmail.com>
Date: Fri, 17 Oct 2025 02:58:49 +0200
Subject: [PATCH 2/3] Apply suggestion

---
 src/serialization.jl | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/serialization.jl b/src/serialization.jl
index c4d7145a..c3358018 100644
--- a/src/serialization.jl
+++ b/src/serialization.jl
@@ -37,8 +37,7 @@ end
 # This method may be removed if the upstream issue is fixed.
 function JSON.lower(x::BenchmarkGroup)
     d = Dict{String,Any}(
-        "data" => Dict(string(k) => v for (k, v) in x.data),
-        "tags" => x.tags,
+        "data" => Dict(string(k) => v for (k, v) in x.data), "tags" => x.tags
     )
     return ["BenchmarkGroup", d]
 end

From 71d0cf8cbf9fa3ac4f6d49d60d138b2f8a92e383 Mon Sep 17 00:00:00 2001
From: Valentin Churavy <v.churavy@gmail.com>
Date: Thu, 16 Oct 2025 21:01:09 -0400
Subject: [PATCH 3/3] bump version

---
 Project.toml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Project.toml b/Project.toml
index a28cb5a8..9ef95106 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,6 +1,6 @@
 name = "BenchmarkTools"
 uuid = "6e4b80f9-dd63-53aa-95a3-0cdb28fa8baf"
-version = "1.6.1"
+version = "1.6.2"
 
 [deps]
 Compat = "34da2185-b29b-5c13-b0c7-acf172513d20"