nixos/hercules-ci-agent: Remove patchNix

nixos/modules/services/continuous-integration/hercules-ci-agent/common.nix

@@ -9,7 +9,15 @@ Platform-specific code is in the respective default.nix files.
 { config, lib, options, pkgs, ... }:
 
 let
-  inherit (lib) mkOption mkIf types filterAttrs literalExample mkRenamedOptionModule;
+  inherit (lib)
+    filterAttrs
+    literalExample
+    mkIf
+    mkOption
+    mkRemovedOptionModule
+    mkRenamedOptionModule
+    types
+    ;
 
   cfg =
     config.services.hercules-ci-agent;
@@ -77,10 +85,11 @@ let
     };
   };
 
+  # TODO (2022) remove
   checkNix =
     if !cfg.checkNix
     then ""
-    else if lib.versionAtLeast config.nix.package.version "2.4.0"
+    else if lib.versionAtLeast config.nix.package.version "2.3.10"
     then ""
     else pkgs.stdenv.mkDerivation {
       name = "hercules-ci-check-system-nix-src";
@@ -88,23 +97,12 @@ let
       configurePhase = ":";
       buildPhase = ''
         echo "Checking in-memory pathInfoCache expiry"
-        if ! grep 'struct PathInfoCacheValue' src/libstore/store-api.hh >/dev/null; then
+        if ! grep 'PathInfoCacheValue' src/libstore/store-api.hh >/dev/null; then
           cat 1>&2 <<EOF
 
           You are deploying Hercules CI Agent on a system with an incompatible
-          nix-daemon. Please
-           - either upgrade Nix to version 2.4.0 (when released),
-           - or set option services.hercules-ci-agent.patchNix = true;
-           - or set option nix.package to a build of Nix 2.3 with this patch applied:
-               https://github.com/NixOS/nix/pull/3405
-
-          The patch is required for Nix-daemon clients that expect a change in binary
-          cache contents while running, like the agent's evaluator. Without it, import
-          from derivation will fail if your cluster has more than one machine.
-          We are conservative with changes to the overall system, which is why we
-          keep changes to a minimum and why we ask for confirmation in the form of
-          services.hercules-ci-agent.patchNix = true before applying.
-
+          nix-daemon. Please make sure nix.package is set to a Nix version of at
+          least 2.3.10 or a master version more recent than Mar 12, 2020.
         EOF
           exit 1
         fi
@@ -112,26 +110,13 @@ let
       installPhase = "touch $out";
     };
 
-  patchedNix = lib.mkIf (!lib.versionAtLeast pkgs.nix.version "2.4.0") (
-    if lib.versionAtLeast pkgs.nix.version "2.4pre"
-    then lib.warn "Hercules CI Agent module will not patch 2.4 pre-release. Make sure it includes (equivalently) PR #3043, commit d048577909 or is no older than 2020-03-13." pkgs.nix
-    else pkgs.nix.overrideAttrs (
-      o: {
-        patches = (o.patches or []) ++ [ backportNix3398 ];
-      }
-    )
-  );
-
-  backportNix3398 = pkgs.fetchurl {
-    url = "https://raw.githubusercontent.com/hercules-ci/hercules-ci-agent/hercules-ci-agent-0.7.3/for-upstream/issue-3398-path-info-cache-ttls-backport-2.3.patch";
-    sha256 = "0jfckqjir9il2il7904yc1qyadw366y7xqzg81sp9sl3f1pw70ib";
-  };
 in
 {
   imports = [
     (mkRenamedOptionModule ["services" "hercules-ci-agent" "extraOptions"] ["services" "hercules-ci-agent" "settings"])
     (mkRenamedOptionModule ["services" "hercules-ci-agent" "baseDirectory"] ["services" "hercules-ci-agent" "settings" "baseDirectory"])
     (mkRenamedOptionModule ["services" "hercules-ci-agent" "concurrentTasks"] ["services" "hercules-ci-agent" "settings" "concurrentTasks"])
+    (mkRemovedOptionModule ["services" "hercules-ci-agent" "patchNix"] "Nix versions packaged in this version of Nixpkgs don't need a patched nix-daemon to work correctly in Hercules CI Agent clusters.")
   ];
 
   options.services.hercules-ci-agent = {
@@ -147,15 +132,6 @@ in
         Support is available at <link xlink:href="mailto:help@hercules-ci.com">help@hercules-ci.com</link>.
       '';
     };
-    patchNix = mkOption {
-      type = types.bool;
-      default = false;
-      description = ''
-        Fix Nix 2.3 cache path metadata caching behavior. Has the effect of <literal>nix.package = patch pkgs.nix;</literal>
-
-        This option will be removed when Hercules CI Agent moves to Nix 2.4 (upcoming Nix release).
-      '';
-    };
     checkNix = mkOption {
       type = types.bool;
       default = true;
@@ -206,7 +182,6 @@ in
       # even shortly after the previous lookup. This *also* applies to the daemon.
       narinfo-cache-negative-ttl = 0
     '';
-    nix.package = mkIf cfg.patchNix patchedNix;
     services.hercules-ci-agent.tomlFile =
       format.generate "hercules-ci-agent.toml" cfg.settings;
   };