From e43e288d5eca104a1dbc6ce4066a505dfb331930 Mon Sep 17 00:00:00 2001
From: Kaidong Hu <hukaidonghkd@gmail.com>
Date: Wed, 28 Jan 2026 21:50:55 -0500
Subject: [PATCH 1/2] test: add docSupport test and add docSupport version
 check

There is a do-install-doc issue related to ruby version < 3.4.
This commit checks doc support for ruby version >= 3.4 and add guard
perventing docSupport be used in parallel build with early versions.

See: https://github.com/ruby/rubygems/issues/7580
---
 flake.nix               | 25 ++++++++++++++++++++++++-
 ruby/package-fn.nix     | 13 ++++++++++---
 rubygems/package-fn.nix |  1 +
 3 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/flake.nix b/flake.nix
index 7d6718a..c1dd1e6 100644
--- a/flake.nix
+++ b/flake.nix
@@ -34,7 +34,7 @@
             { version, versionSource }:
             let
               pkg = pkgs.callPackage packageFn {
-                inherit version versionSource;
+                inherit version versionSource versionComparison;
               };
             in
             applyOverrides {
@@ -219,6 +219,29 @@
                 '';
               };
             })
+            // (lib.optionalAttrs (with versionComparison rubyVersion; greaterOrEqualTo "3.4") {
+              docSupport = {
+                nativeBuildInputs = [
+                  (ruby.override { docSupport = true; })
+                ];
+                command = ''
+                  ri Array > $out
+                '';
+              };
+            })
+            // (lib.optionalAttrs (with versionComparison rubyVersion; lessThan "3.4") {
+              docSupport-noParallel = {
+                nativeBuildInputs = [
+                  (ruby.override {
+                    docSupport = true;
+                    parallelBuild = false;
+                  })
+                ];
+                command = ''
+                  ri Array > $out
+                '';
+              };
+            })
             // (lib.optionalAttrs (with versionComparison rubyVersion; greaterOrEqualTo "2.2") {
               bundlerEnv =
                 let
diff --git a/ruby/package-fn.nix b/ruby/package-fn.nix
index 9ad96dd..0107e38 100644
--- a/ruby/package-fn.nix
+++ b/ruby/package-fn.nix
@@ -1,6 +1,8 @@
 {
   version,
-  versionSource,
+  versionSource
+, versionComparison
+,
   libDir ? "${(import ./parse-version.nix version).majMin}.0",
   rubygems ? null,
   stdenv,
@@ -25,7 +27,9 @@
   buildEnv,
   bundler,
   bundix,
-  removeReferencesTo,
+  removeReferencesTo
+, parallelBuild ? true
+,
   useRailsExpress ? true,
   zlibSupport ? true,
   opensslSupport ? true,
@@ -89,7 +93,7 @@ let
       ]);
     propagatedBuildInputs = (op jemallocSupport jemalloc);
 
-    enableParallelBuilding = true;
+    enableParallelBuilding = parallelBuild;
 
     postPatch = ''
       ${opString (rubygems != null) ''
@@ -200,4 +204,7 @@ let
     };
   };
 in
+# There's a known race condition when building with docs enabled before Ruby 3.4.0
+# Building documents requires parallelBuild to be false in those versions
+assert docSupport -> (with versionComparison version; greaterOrEqualTo "3.4.0" || !parallelBuild);
 self
diff --git a/rubygems/package-fn.nix b/rubygems/package-fn.nix
index b89761c..d43957c 100644
--- a/rubygems/package-fn.nix
+++ b/rubygems/package-fn.nix
@@ -4,6 +4,7 @@
   stdenv,
   fetchurl,
   fetchpatch,
+  ...
 }:
 stdenv.mkDerivation {
   pname = "rubygems";

From 7a8f6574b724774a5342311e2abd93002205d506 Mon Sep 17 00:00:00 2001
From: Kaidong Hu <hukaidonghkd@gmail.com>
Date: Sat, 11 Apr 2026 14:37:19 -0400
Subject: [PATCH 2/2] Fix docSupport build failure in Nix sandbox

rdoc tries to create XDG_DATA_DIR (defaulting to $HOME/.local/share) during the build, but $HOME is read-only in the Nix sandbox.

This adds a writable $HOME during the preConfigure phase, and applies the
same fix to the docSupport tests in flake.nix.

See: https://github.com/bobvanderlinden/nixpkgs-ruby/pull/221

Co-Authored-By: Sander <hey@sandydoo.me>
---
 flake.nix           | 4 ++--
 ruby/package-fn.nix | 5 +++++
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/flake.nix b/flake.nix
index c1dd1e6..6dcdbff 100644
--- a/flake.nix
+++ b/flake.nix
@@ -225,7 +225,7 @@
                   (ruby.override { docSupport = true; })
                 ];
                 command = ''
-                  ri Array > $out
+                  HOME=$TMPDIR ri Array > $out
                 '';
               };
             })
@@ -238,7 +238,7 @@
                   })
                 ];
                 command = ''
-                  ri Array > $out
+                  HOME=$TMPDIR ri Array > $out
                 '';
               };
             })
diff --git a/ruby/package-fn.nix b/ruby/package-fn.nix
index 0107e38..9f07b8c 100644
--- a/ruby/package-fn.nix
+++ b/ruby/package-fn.nix
@@ -113,6 +113,11 @@ let
 
     preConfigure = ''
       sed -i configure -e 's/;; #(/\n;;/g'
+      ${opString docSupport ''
+        # rdoc creates XDG_DATA_DIR (defaulting to $HOME/.local/share) even if
+        # it's not going to be used.
+        export HOME=$TMPDIR
+      ''}
     '';
 
     configureFlags =