From 4d4563b9d8c685407b56e1d472c7104a5d8a9b6a Mon Sep 17 00:00:00 2001
From: matthiasdotsh <git@matthias.sh>
Date: Fri, 2 Jan 2026 13:19:47 +0100
Subject: [PATCH] kaldi: add openfst patch for building with gcc15

---
 .../ka/kaldi/fix-gcc15-copy-constructor.patch | 42 +++++++++++++++++++
 pkgs/by-name/ka/kaldi/package.nix             | 11 +++--
 2 files changed, 50 insertions(+), 3 deletions(-)
 create mode 100644 pkgs/by-name/ka/kaldi/fix-gcc15-copy-constructor.patch

diff --git a/pkgs/by-name/ka/kaldi/fix-gcc15-copy-constructor.patch b/pkgs/by-name/ka/kaldi/fix-gcc15-copy-constructor.patch
new file mode 100644
index 000000000000..339a38ca0901
--- /dev/null
+++ b/pkgs/by-name/ka/kaldi/fix-gcc15-copy-constructor.patch
@@ -0,0 +1,42 @@
+From fece8a6f239c7323c61238dfdd1e0dd47885fc88 Mon Sep 17 00:00:00 2001
+From: matthiasdotsh <git@matthias.sh>
+Date: Fri, 2 Jan 2026 11:08:17 +0100
+Subject: [PATCH] Fix copy constructor member access in VectorHashBiTable
+
+The copy constructor of VectorHashBiTable was incorrectly accessing
+`table.s_` instead of `table.selector_`, causing a compilation error
+with stricter C++ compilers.
+
+This issue manifests with GCC 15, which enforces more rigorous checks
+on template member access. The compiler error was:
+
+  error: 'const class fst::VectorHashBiTable<...>' has no member
+  named 's_'; did you mean 'h_'?
+
+The member variable is actually named `selector_`, not `s_`. This fix
+aligns the copy constructor with the correct member variable name used
+throughout the class definition.
+
+Fixes build failures on systems with GCC 15.
+
+Related: https://github.com/gpustack/gpustack/issues/1798#issuecomment-2980869111
+---
+ src/include/fst/bi-table.h | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/src/include/fst/bi-table.h b/src/include/fst/bi-table.h
+index 9651cfe..fb747fe 100644
+--- a/src/include/fst/bi-table.h
++++ b/src/include/fst/bi-table.h
+@@ -317,7 +317,7 @@ class VectorHashBiTable {
+   }
+ 
+   VectorHashBiTable(const VectorHashBiTable<I, T, S, FP, H, HS> &table)
+-      : selector_(new S(table.s_)), fp_(new FP(*table.fp_)),
++      : selector_(new S(table.selector_)), fp_(new FP(*table.fp_)),
+         h_(new H(*table.h_)), id2entry_(table.id2entry_),
+         fp2id_(table.fp2id_), hash_func_(*this), hash_equal_(*this),
+         keys_(table.keys_.size(), hash_func_, hash_equal_) {
+-- 
+2.52.0
+
diff --git a/pkgs/by-name/ka/kaldi/package.nix b/pkgs/by-name/ka/kaldi/package.nix
index 5703c366f9ff..f9684beb108f 100644
--- a/pkgs/by-name/ka/kaldi/package.nix
+++ b/pkgs/by-name/ka/kaldi/package.nix
@@ -73,9 +73,14 @@ stdenv.mkDerivation (finalAttrs: {
         owner = "kkm000";
         repo = "openfst";
         rev = "338225416178ac36b8002d70387f5556e44c8d05";
-        hash = "sha256-y1E6bQgBfYt1Co02UutOyEM2FnETuUl144tHwypiX+M=";
-        # https://github.com/kkm000/openfst/issues/59
-        postFetch = ''(cd "$out"; patch -p1 < '${./gcc14.patch}')'';
+        hash = "sha256-9xsL78mkR40zkoRYWsH+iaPa5MYc4BzwslzxGKv4j4I=";
+        postFetch = ''
+          cd "$out"
+          # https://github.com/kkm000/openfst/issues/59
+          patch -p1 < ${./gcc14.patch}
+          # Patch for compiling openfst with gcc >= 15
+          patch -p1 < ${./fix-gcc15-copy-constructor.patch}
+        '';
       };
     };