From ac0f095cfb66f1085f8bbe2e9daa7f23e3128887 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?M=C3=A1rton=20Boros?= <martonboros@gmail.com>
Date: Fri, 31 Jul 2026 07:14:52 +0300
Subject: [PATCH] fix(nix): pin cgal to 6.0.2 in overlay to unbreak
 sfcgal/postgis

nixpkgs' cgal bump to 6.1 removed CGAL::Polygon_mesh_processing::surface_intersection,
which sfcgal 2.2.0 (still the packaged version) depends on, breaking postgis builds.
---
 nix/overlays/default.nix | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/nix/overlays/default.nix b/nix/overlays/default.nix
index c2a6e5976d..6a0daa1f70 100644
--- a/nix/overlays/default.nix
+++ b/nix/overlays/default.nix
@@ -1,6 +1,6 @@
 { self, ... }:
 {
-  flake.overlays.default = final: _prev: {
+  flake.overlays.default = final: prev: {
     # NOTE: add any needed overlays here. in theory we could
     # pull them from the overlays/ directory automatically, but we don't
     # want to have an arbitrary order, since it might matter. being
@@ -17,6 +17,15 @@
 
     xmrig = throw "The xmrig package has been explicitly disabled in this flake.";
 
+    # Hold cgal back to 6.0.2 until nixpkgs bumps sfcgal past 2.2.0 (incompatible with CGAL 6.1+).
+    cgal = prev.cgal.overrideAttrs (_: {
+      version = "6.0.2";
+      src = final.fetchurl {
+        url = "https://github.com/CGAL/cgal/releases/download/v6.0.2/CGAL-6.0.2.tar.xz";
+        sha256 = "sha256-8wxb58JaKj6iS8y6q1z2P6/aY8AnnzTX5/izISgh/tY=";
+      };
+    });
+
     cargo-pgrx = final.callPackage ../cargo-pgrx/default.nix {
       inherit (final) lib;
       inherit (final) fetchCrate;