From f4a0bb8334dbfef6e092078a78d78572ad3d6730 Mon Sep 17 00:00:00 2001
From: Alyssa Ross <hi@alyssa.is>
Date: Sat, 2 Apr 2022 11:17:46 +0000
Subject: nixos/mailman: improve empty webHosts error

Now this configuration mistake will generate the assertion message,
instead of "error: list index 0 is out of bounds".
---
 nixos/modules/services/mail/mailman.nix | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/nixos/modules/services/mail/mailman.nix b/nixos/modules/services/mail/mailman.nix
index 0c9b38b44b24d..2183f22cbde8c 100644
--- a/nixos/modules/services/mail/mailman.nix
+++ b/nixos/modules/services/mail/mailman.nix
@@ -225,7 +225,14 @@ in {
               See <https://mailman.readthedocs.io/en/latest/src/mailman/docs/mta.html>.
             '';
           };
-    in (lib.optionals cfg.enablePostfix [
+    in [
+      { assertion = cfg.webHosts != [];
+        message = ''
+          services.mailman.serve.enable requires there to be at least one entry
+          in services.mailman.webHosts.
+        '';
+      }
+    ] ++ (lib.optionals cfg.enablePostfix [
       { assertion = postfix.enable;
         message = ''
           Mailman's default NixOS configuration requires Postfix to be enabled.
@@ -275,7 +282,7 @@ in {
           globals().update(json.load(f))
     '';
 
-    services.nginx = mkIf cfg.serve.enable {
+    services.nginx = mkIf (cfg.serve.enable && cfg.webHosts != []) {
       enable = mkDefault true;
       virtualHosts."${lib.head cfg.webHosts}" = {
         serverAliases = cfg.webHosts;
-- 
cgit 1.4.1