From 6a25a35e704689d2bfa6c39032844674e6fdb3fd Mon Sep 17 00:00:00 2001
From: Samuel Dionne-Riel <samuel@dionne-riel.com>
Date: Sun, 5 Aug 2018 19:15:14 -0400
Subject: [PATCH] nixos/activation: Identifies the snippet that failed

This allows a developer to better identify in which snippet the
failure happened. Furthermore, users seeking help will have more
information available about the failure.
---
 nixos/modules/system/activation/activation-script.nix | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/nixos/modules/system/activation/activation-script.nix b/nixos/modules/system/activation/activation-script.nix
index c563614caaaf..93a1b13a81dd 100644
--- a/nixos/modules/system/activation/activation-script.nix
+++ b/nixos/modules/system/activation/activation-script.nix
@@ -8,7 +8,12 @@ let
   addAttributeName = mapAttrs (a: v: v // {
     text = ''
       #### Activation script snippet ${a}:
+      _localstatus=0
       ${v.text}
+
+      if (( _localstatus > 0 )); then
+        printf "Activation script snippet '%s' failed (%s)\n" "${a}" "$_localstatus"
+      fi
     '';
   });
 
@@ -71,7 +76,7 @@ in
             done
 
             _status=0
-            trap "_status=1" ERR
+            trap "_status=1 _localstatus=\$?" ERR
 
             # Ensure a consistent umask.
             umask 0022