From 4312cfdbda1855088905a3d9959a4fac362fd051 Mon Sep 17 00:00:00 2001
From: Graham Christensen <graham@grahamc.com>
Date: Fri, 5 Oct 2018 10:48:42 -0400
Subject: version.nix: extract revision-fetching function

---
 lib/trivial.nix | 10 ++++++++++
 1 file changed, 10 insertions(+)

(limited to 'lib')

diff --git a/lib/trivial.nix b/lib/trivial.nix
index b1eea0bf1247..938df6ced476 100644
--- a/lib/trivial.nix
+++ b/lib/trivial.nix
@@ -105,6 +105,16 @@ rec {
     then lib.strings.fileContents suffixFile
     else "pre-git";
 
+  # Attempt to get the revision nixpkgs is from
+  revisionWithDefault = default:
+    let
+      revisionFile = "${toString ./..}/.git-revision";
+      gitRepo      = "${toString ./..}/.git";
+    in if lib.pathIsDirectory gitRepo
+       then lib.commitIdFromGitRepo gitRepo
+       else if lib.pathExists revisionFile then lib.fileContents revisionFile
+       else default;
+
   nixpkgsVersion = builtins.trace "`lib.nixpkgsVersion` is deprecated, use `lib.version` instead!" version;
 
   # Whether we're being called by nix-shell.
-- 
cgit 1.4.1