From 01a68479cc08d4f937a93c27f8f36e701e4bd435 Mon Sep 17 00:00:00 2001
From: Antoine Eiche <lewo@abesis.fr>
Date: Thu, 30 Jan 2020 10:43:15 +0100
Subject: dockerTools.buildLayeredImage: assert maxLayers > 1

Since a layer is reserved for "customization", the image can not
contains less than 2 layers.

The user gets the following message at evaluation:

    nix-instantiate nixos/tests/docker-tools.nix
    trace: the maxLayers argument of dockerTools.buildLayeredImage function must be greather than 1 (current value: 1)
---
 pkgs/build-support/docker/default.nix | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'pkgs')

diff --git a/pkgs/build-support/docker/default.nix b/pkgs/build-support/docker/default.nix
index 9f831d48bfa..509b7e2a7e1 100644
--- a/pkgs/build-support/docker/default.nix
+++ b/pkgs/build-support/docker/default.nix
@@ -545,6 +545,9 @@ rec {
     # believe the actual maximum is 128.
     maxLayers ? 100
   }:
+    assert
+      (lib.assertMsg (maxLayers > 1)
+      "the maxLayers argument of dockerTools.buildLayeredImage function must be greather than 1 (current value: ${toString maxLayers})");
     let
       baseName = baseNameOf name;
       contentsEnv = symlinkJoin {
-- 
cgit 1.4.1