From 4ded9beea2ea5d0dd739c78a5bf1e5f42a1e1c39 Mon Sep 17 00:00:00 2001
From: Chuck <chuck@intelligence.org>
Date: Mon, 16 Sep 2019 08:21:54 -0700
Subject: [PATCH] Add note: Keep error message in sync with nixos-option

---
 lib/modules.nix | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/modules.nix b/lib/modules.nix
index 71672c7d112b..44db77b5d1c6 100644
--- a/lib/modules.nix
+++ b/lib/modules.nix
@@ -326,6 +326,8 @@ rec {
 
       # The value with a check that it is defined
       valueDefined = if res.isDefined then res.mergedValue else
+        # (nixos-option detects this specific error message and gives it special
+        # handling.  If changed here, please change it there too.)
         throw "The option `${showOption loc}' is used but not defined.";
 
       # Apply the 'apply' function to the merged value. This allows options to