From 5c8bac0971dd2895c0989b3b8c3392e812b54e39 Mon Sep 17 00:00:00 2001
From: Andrew Marshall <andrew@johnandrewmarshall.com>
Date: Sat, 18 Jul 2026 20:43:59 -0400
Subject: [PATCH] expat: make version easily overridable
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Previously, doing e.g.

```
expat.overrideAttrs (old: {
  version = "2.8.1";
  src = old.src.overrideAttrs { hash = ""; };
})
```

would not work since `tag` was created outside `mkDerivation` using
`version`, not `finalAttrs.version`. Most sensible perhaps would be to
move it inside (e.g. `mkDerivation (finalAttrs: let tag = … in …`),
however then `nix fmt` wants to indent everything. So instead keep it
outside but make it a fn that takes the version, and always use
`finalAttrs.version`.
---
 pkgs/by-name/ex/expat/package.nix | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/pkgs/by-name/ex/expat/package.nix b/pkgs/by-name/ex/expat/package.nix
index 72459e1c2ac6..2e831ef025da 100644
--- a/pkgs/by-name/ex/expat/package.nix
+++ b/pkgs/by-name/ex/expat/package.nix
@@ -18,17 +18,17 @@
 # files.
 
 let
-  version = "2.8.2";
-  tag = "R_${lib.replaceStrings [ "." ] [ "_" ] version}";
+  tagFor = version: "R_${lib.replaceStrings [ "." ] [ "_" ] version}";
 in
+
 stdenv.mkDerivation (finalAttrs: {
   pname = "expat";
-  inherit version;
+  version = "2.8.2";
 
   src = fetchurl {
     url =
       with finalAttrs;
-      "https://github.com/libexpat/libexpat/releases/download/${tag}/${pname}-${version}.tar.xz";
+      "https://github.com/libexpat/libexpat/releases/download/${tagFor version}/${pname}-${version}.tar.xz";
     hash = "sha256-OtibhYjmZEvU5JmBSA1IshKJ7rvNTwoaSvscKfmbarQ=";
   };
 
@@ -73,7 +73,7 @@ stdenv.mkDerivation (finalAttrs: {
   };
 
   meta = {
-    changelog = "https://github.com/libexpat/libexpat/blob/${tag}/expat/Changes";
+    changelog = "https://github.com/libexpat/libexpat/blob/${tagFor finalAttrs.version}/expat/Changes";
     homepage = "https://libexpat.github.io/";
     description = "Stream-oriented XML parser library written in C";
     mainProgram = "xmlwf";