From 6ef1eb9ce1e649727f3c113354e7ac204b5c56ba Mon Sep 17 00:00:00 2001
From: emilylange <git@emilylange.de>
Date: Sat, 21 Jun 2025 20:15:46 +0200
Subject: [PATCH] assertions: fix eval error when `mailserver.stateVersion` is
 unset (null)
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Eval does not stop on the first assertion failure it encouters.
Instead, it tries to evaluate all assertions and returns with a list of
those that failed.

This means our very top `config.mailserver.stateVersion != null`
assertion does not gate against any other assertions trying to compare
null against an integer.

The error prior to this commit can be reproduced by removing
`mailserver.stateVersion = 999;` in tests/lib/config.nix and then trying
to evaluate any of the tests:

~~~bash
# nix eval --raw .#checks.x86_64-linux.internal-unstable
error:
       … while evaluating the attribute 'outPath'
         at /nix/store/syvnmj3hhckkbncm94kfkbl76qsdqqj3-source/lib/customisation.nix:421:7:
          420|         drv.drvPath;
          421|       outPath =
             |       ^
          422|         assert condition;

       … while calling the 'getAttr' builtin
         at «internal»:1:500:
       (stack trace truncated; use '--show-trace' to show the full trace)

       error: cannot compare null with an integer
~~~
---
 docs/howto-develop.rst     | 2 +-
 mail-server/assertions.nix | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/docs/howto-develop.rst b/docs/howto-develop.rst
index dbf3024..700f9d0 100644
--- a/docs/howto-develop.rst
+++ b/docs/howto-develop.rst
@@ -85,7 +85,7 @@ section on the migration page in the documentation.
   {
     assertions = [
       {
-        assertion = config.mailserver.stateVersion >= 1;
+        assertion = config.mailserver.stateVersion != null -> config.mailserver.stateVersion >= 1;
         message = ''
           Problem: The home directory for the foobar service is snafu.
           Remediation:
diff --git a/mail-server/assertions.nix b/mail-server/assertions.nix
index 929f592..c606bda 100644
--- a/mail-server/assertions.nix
+++ b/mail-server/assertions.nix
@@ -26,7 +26,7 @@
       lib.optionals (config.mailserver.ldap.enable && config.mailserver.mailDirectory != "/var/vmail")
         [
           {
-            assertion = config.mailserver.stateVersion >= 2;
+            assertion = config.mailserver.stateVersion != null -> config.mailserver.stateVersion >= 2;
             message = ''
               Issue: The dovecot homedir for LDAP users was previously not respecting `mailserver.mailDirectory`.
               Remediation:
@@ -40,7 +40,7 @@
         ]
     ++ [
       {
-        assertion = config.mailserver.stateVersion >= 3;
+        assertion = config.mailserver.stateVersion != null -> config.mailserver.stateVersion >= 3;
         message = ''
           Issue: The dovecot mail location for all users has changed and need to be migrated.