From b428932fc61d6d4b932fedf749bfcc0c5455f606 Mon Sep 17 00:00:00 2001
From: sternenseemann <sternenseemann@systemli.org>
Date: Wed, 18 Mar 2026 23:33:55 +0100
Subject: [PATCH] nixVersions.*: patch for compatibility with lowdown >= 3.0

---
 pkgs/tools/package-management/nix/default.nix | 47 ++++++++++++++-----
 .../lowdown-3.0-compat-2.28-2.30.patch        | 27 +++++++++++
 2 files changed, 61 insertions(+), 13 deletions(-)
 create mode 100644 pkgs/tools/package-management/nix/patches/lowdown-3.0-compat-2.28-2.30.patch

diff --git a/pkgs/tools/package-management/nix/default.nix b/pkgs/tools/package-management/nix/default.nix
index 8772d9df0b1e..1eb7c5699b06 100644
--- a/pkgs/tools/package-management/nix/default.nix
+++ b/pkgs/tools/package-management/nix/default.nix
@@ -134,6 +134,21 @@ let
   patches_common = lib.optional (
     stdenv.system == "aarch64-darwin"
   ) ./patches/skip-flaky-darwin-tests.patch;
+
+  # Lowdown 3.0 compatibility patch for nix 2.31–2.33; fetched from the
+  # upstream backport (same diff on every maintenance branch after
+  # fetchpatch strips metadata).  Nix 2.34.4+ and the git snapshot
+  # already include the fix in their tagged source.
+  lowdown30Patch = pkgs.fetchpatch {
+    name = "nix-lowdown-3.0-support.patch";
+    url = "https://github.com/NixOS/nix/commit/472c35c561bd9e8db1465e0677f1efe2cb88c568.patch";
+    hash = "sha256-ZCQgI/euBN8t9rgdCsGRgrcEWG3T5MUc+bQc4tIcHuI=";
+  };
+
+  # Lowdown 3.0 compatibility patch for nix 2.28 and 2.30, which have a
+  # different markdown.cc layout (no LOWDOWN_TERM_NORELLINK branch) and
+  # never received an upstream backport.
+  lowdown30PatchOld = ./patches/lowdown-3.0-compat-2.28-2.30.patch;
 in
 lib.makeExtensible (
   self:
@@ -149,6 +164,7 @@ lib.makeExtensible (
             url = "https://github.com/NixOS/nix/commit/5a64138e862fe364e751c5c286e8db8c466aaee7.patch?full_index=1";
             hash = "sha256-vFv/D08x9urtoIE9wiC7Lln4Eq3sgNBwU7TBE1iyrfI=";
           })
+          lowdown30PatchOld
         ];
       };
 
@@ -172,22 +188,27 @@ lib.makeExtensible (
                 url = "https://github.com/NixOS/nix/commit/5cbd7856de0a9c13351f98e32a1e26d0854d87fd.patch?full_index=1";
                 hash = "sha256-r2ZF1zBZDKMvyX6X4VsaTMrg0zdjn59Jf6Hqg56r29E=";
               })
+              lowdown30PatchOld
             ]
           );
 
       nix_2_30 = addTests "nix_2_30" self.nixComponents_2_30.nix-everything;
 
-      nixComponents_2_31 = nixDependencies.callPackage ./modular/packages.nix rec {
-        version = "2.31.3";
-        inherit (self.nix_2_30.meta) teams;
-        otherSplices = generateSplicesForNixComponents "nixComponents_2_31";
-        src = fetchFromGitHub {
-          owner = "NixOS";
-          repo = "nix";
-          tag = version;
-          hash = "sha256-oe0YWe8f+pwQH4aYD2XXLW5iEHyXNUddurqJ5CUVCIk=";
-        };
-      };
+      nixComponents_2_31 =
+        (nixDependencies.callPackage ./modular/packages.nix rec {
+          version = "2.31.3";
+          inherit (self.nix_2_30.meta) teams;
+          otherSplices = generateSplicesForNixComponents "nixComponents_2_31";
+          src = fetchFromGitHub {
+            owner = "NixOS";
+            repo = "nix";
+            tag = version;
+            hash = "sha256-oe0YWe8f+pwQH4aYD2XXLW5iEHyXNUddurqJ5CUVCIk=";
+          };
+        }).appendPatches
+          [
+            lowdown30Patch
+          ];
 
       nix_2_31 = addTests "nix_2_31" self.nixComponents_2_31.nix-everything;
 
@@ -203,7 +224,7 @@ lib.makeExtensible (
             hash = "sha256-5aH3xppfBs8j6P7A2wq8WQ05yJvlL7x0gQbWk4RN5eY=";
           };
         }).appendPatches
-          patches_common;
+          (patches_common ++ [ lowdown30Patch ]);
 
       nix_2_32 = addTests "nix_2_32" self.nixComponents_2_32.nix-everything;
 
@@ -219,7 +240,7 @@ lib.makeExtensible (
             hash = "sha256-2Mga4e9ZtOPLwYqF4+hcjdsTImcA7TKUvDDfaF7jqEo=";
           };
         }).appendPatches
-          patches_common;
+          (patches_common ++ [ lowdown30Patch ]);
 
       nix_2_33 = addTests "nix_2_33" self.nixComponents_2_33.nix-everything;
 
diff --git a/pkgs/tools/package-management/nix/patches/lowdown-3.0-compat-2.28-2.30.patch b/pkgs/tools/package-management/nix/patches/lowdown-3.0-compat-2.28-2.30.patch
new file mode 100644
index 000000000000..dd527f7f1cd6
--- /dev/null
+++ b/pkgs/tools/package-management/nix/patches/lowdown-3.0-compat-2.28-2.30.patch
@@ -0,0 +1,27 @@
+--- a/src/libcmd/markdown.cc
++++ b/src/libcmd/markdown.cc
+@@ -37,7 +37,13 @@
+         .vmargin = 0,
+ #  endif
+         .feat = LOWDOWN_COMMONMARK | LOWDOWN_FENCED | LOWDOWN_DEFLIST | LOWDOWN_TABLES,
+-        .oflags = LOWDOWN_TERM_NOLINK,
++        .oflags =
++#  if HAVE_LOWDOWN_3
++            LOWDOWN_NOLINK
++#  else
++            LOWDOWN_TERM_NOLINK
++#  endif
++        ,
+     };
+
+     auto doc = lowdown_doc_new(&opts);
+--- a/src/libcmd/meson.build
++++ b/src/libcmd/meson.build
+@@ -36,6 +36,7 @@
+ configdata.set('HAVE_LOWDOWN', lowdown.found().to_int())
+ # The API changed slightly around terminal initialization.
+ configdata.set('HAVE_LOWDOWN_1_4', lowdown.version().version_compare('>= 1.4.0').to_int())
++configdata.set('HAVE_LOWDOWN_3', lowdown.version().version_compare('>= 3.0.0').to_int())
+
+ readline_flavor = get_option('readline-flavor')
+ if readline_flavor == 'editline'