From 169c6b4b1478a3a0c823c99ea39d4082f76a2708 Mon Sep 17 00:00:00 2001
From: Robert Hensing <robert@roberthensing.nl>
Date: Mon, 22 Mar 2021 21:37:54 +0100
Subject: [PATCH] nixosTest: Make system.nixos.revision constant

Make the revision metadata constant, in order to avoid needless retesting.

The human version (e.g. 21.05-pre) is left as is, because it is useful
for external modules that test with e.g. nixosTest and rely on that
version number.
---
 nixos/lib/build-vms.nix | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/nixos/lib/build-vms.nix b/nixos/lib/build-vms.nix
index ebbb0296bef..064e44f643b 100644
--- a/nixos/lib/build-vms.nix
+++ b/nixos/lib/build-vms.nix
@@ -36,6 +36,13 @@ rec {
         [ ../modules/virtualisation/qemu-vm.nix
           ../modules/testing/test-instrumentation.nix # !!! should only get added for automated test runs
           { key = "no-manual"; documentation.nixos.enable = false; }
+          { key = "no-revision";
+            # Make the revision metadata constant, in order to avoid needless retesting.
+            # The human version (e.g. 21.05-pre) is left as is, because it is useful
+            # for external modules that test with e.g. nixosTest and rely on that
+            # version number.
+            config.system.nixos.revision = "constant-nixos-revision";
+          }
           { key = "nodes"; _module.args.nodes = nodes; }
         ] ++ optional minimal ../modules/testing/minimal-kernel.nix;
     };