From 6af2f8a95b385e4e468452f9d5c4ca9129dde711 Mon Sep 17 00:00:00 2001
From: Kirill Radzikhovskyy <kirillrdy@gmail.com>
Date: Wed, 15 Oct 2025 19:26:36 +1100
Subject: [PATCH] avro-cpp: fix build with fmt 11

Add patches to make fmt formatters const, as required by fmt 11.
---
 .../av/avro-cpp/0002-fix-fmt-name-formatter.patch     | 11 +++++++++++
 .../av/avro-cpp/0003-fix-fmt-type-formatter.patch     | 11 +++++++++++
 pkgs/by-name/av/avro-cpp/package.nix                  |  4 ++++
 3 files changed, 26 insertions(+)
 create mode 100644 pkgs/by-name/av/avro-cpp/0002-fix-fmt-name-formatter.patch
 create mode 100644 pkgs/by-name/av/avro-cpp/0003-fix-fmt-type-formatter.patch

diff --git a/pkgs/by-name/av/avro-cpp/0002-fix-fmt-name-formatter.patch b/pkgs/by-name/av/avro-cpp/0002-fix-fmt-name-formatter.patch
new file mode 100644
index 000000000000..9fc82840b61b
--- /dev/null
+++ b/pkgs/by-name/av/avro-cpp/0002-fix-fmt-name-formatter.patch
@@ -0,0 +1,11 @@
+diff --git a/include/avro/Node.hh b/include/avro/Node.hh
+--- a/include/avro/Node.hh
++++ b/include/avro/Node.hh
+@@ -219,7 +219,7 @@ template<>
+ struct fmt::formatter<avro::Name> : fmt::formatter<std::string> {
+     template<typename FormatContext>
+-    auto format(const avro::Name &n, FormatContext &ctx) {
++    auto format(const avro::Name &n, FormatContext &ctx) const {
+         return fmt::formatter<std::string>::format(n.fullname(), ctx);
+     }
+ };
\ No newline at end of file
diff --git a/pkgs/by-name/av/avro-cpp/0003-fix-fmt-type-formatter.patch b/pkgs/by-name/av/avro-cpp/0003-fix-fmt-type-formatter.patch
new file mode 100644
index 000000000000..cb13eb4cb915
--- /dev/null
+++ b/pkgs/by-name/av/avro-cpp/0003-fix-fmt-type-formatter.patch
@@ -0,0 +1,11 @@
+diff --git a/include/avro/Types.hh b/include/avro/Types.hh
+--- a/include/avro/Types.hh
++++ b/include/avro/Types.hh
+@@ -113,7 +113,7 @@ template<>
+ struct fmt::formatter<avro::Type> : fmt::formatter<std::string> {
+     template<typename FormatContext>
+-    auto format(avro::Type t, FormatContext &ctx) {
++    auto format(avro::Type t, FormatContext &ctx) const {
+         return fmt::formatter<std::string>::format(avro::toString(t), ctx);
+     }
+ };
\ No newline at end of file
diff --git a/pkgs/by-name/av/avro-cpp/package.nix b/pkgs/by-name/av/avro-cpp/package.nix
index 09f24f5d9621..df6a4b80d39c 100644
--- a/pkgs/by-name/av/avro-cpp/package.nix
+++ b/pkgs/by-name/av/avro-cpp/package.nix
@@ -18,8 +18,12 @@ stdenv.mkDerivation rec {
     hash = "sha256-8u33cSanWw7BrRZncr4Fg1HOo9dESL5+LO8gBQwPmKs=";
   };
 
+  # TODO: remove fmt formatter patches when updating to next version
+  # Patches exist upstream but don't apply cleanly.
   patches = [
     ./0001-get-rid-of-fmt-fetchcontent.patch
+    ./0002-fix-fmt-name-formatter.patch
+    ./0003-fix-fmt-type-formatter.patch
   ];
 
   nativeBuildInputs = [