fetchgit: add 'deepClone' argument to disable shallow fetching

This patch resolves https://github.com/NixOS/nixpkgs/issues/6395. Deep
cloning is useful in combination with 'leaveDotGit' for builds that want
to run "git describe" to obtain a proper version string, etc., like the
'haskellngPackages.cabal2nix' package does.

1 files changed, 4 insertions, 4 deletions

diff --git a/pkgs/build-support/fetchgit/default.nix b/pkgs/build-support/fetchgit/default.nix
index 7dd179f4c8b..bb89a8f5532 100644
--- a/pkgs/build-support/fetchgit/default.nix
+++ b/pkgs/build-support/fetchgit/default.nix
@@ -11,8 +11,8 @@
       else "";
   in "${if matched == null then base else builtins.head matched}${appendShort}";
 in
-{ url, rev ? "HEAD", md5 ? "", sha256 ? "", leaveDotGit ? false
-, fetchSubmodules ? true
+{ url, rev ? "HEAD", md5 ? "", sha256 ? "", leaveDotGit ? deepClone
+, fetchSubmodules ? true, deepClone ? false
 , name ? urlToName url rev
 }:
 
@@ -39,6 +39,7 @@ in
 */
 
 assert md5 != "" || sha256 != "";
+assert deepClone -> leaveDotGit;
 
 stdenv.mkDerivation {
   inherit name;
@@ -50,7 +51,7 @@ stdenv.mkDerivation {
   outputHashMode = "recursive";
   outputHash = if sha256 == "" then md5 else sha256;
 
-  inherit url rev leaveDotGit fetchSubmodules;
+  inherit url rev leaveDotGit fetchSubmodules deepClone;
 
   GIT_SSL_CAINFO = "${cacert}/etc/ca-bundle.crt";
 
@@ -64,4 +65,3 @@ stdenv.mkDerivation {
 
   preferLocalBuild = true;
 }
-