emacs.pkgs.melpaBuild: package-build: 2018-10-05 -> 2021-04-13

I think this is due an update.  I've chosen to update to the latest
version that has been merged into Melpa.

Unfortunately we now need to hack around it trying to run VCS
commands.

My Emacs configuration with thirty-something leaf packages seems fine
after the rebuild.

2 files changed, 7 insertions, 4 deletions

diff --git a/pkgs/build-support/emacs/melpa.nix b/pkgs/build-support/emacs/melpa.nix
index 824611b20c8..c30d3e59906 100644
--- a/pkgs/build-support/emacs/melpa.nix
+++ b/pkgs/build-support/emacs/melpa.nix
@@ -38,8 +38,8 @@ import ./generic.nix { inherit lib stdenv emacs texinfo writeText; } ({
   packageBuild = fetchFromGitHub {
     owner = "melpa";
     repo = "package-build";
-    rev = "0a22c3fbbf661822ec1791739953b937a12fa623";
-    sha256 = "0dpy5p34il600sc8ic5jdgb3glya9si3lrvhxab0swks8fdydjgs";
+    rev = "047801d301a73d4932f33f768d94a8ed26b8d524";
+    sha256 = "0ygzkpg7xc3mjjbxg1kcyz6fwbkb0prvca499f0ffmhfaiv28h59";
   };
 
   elpa2nix = ./elpa2nix.el;
@@ -70,7 +70,7 @@ import ./generic.nix { inherit lib stdenv emacs texinfo writeText; } ({
         -L "$NIX_BUILD_TOP/package-build" \
         -l "$melpa2nix" \
         -f melpa2nix-build-package \
-        $ename $version
+        $ename $version $commit
 
     runHook postBuild
     '';
diff --git a/pkgs/build-support/emacs/melpa2nix.el b/pkgs/build-support/emacs/melpa2nix.el
index 99c755e2afc..bd2aadd5aeb 100644
--- a/pkgs/build-support/emacs/melpa2nix.el
+++ b/pkgs/build-support/emacs/melpa2nix.el
@@ -12,5 +12,8 @@
   (if (not noninteractive)
       (error "`melpa2nix-build-package' is to be used only with -batch"))
   (pcase command-line-args-left
-    (`(,package ,version)
+    (`(,package ,version ,commit)
+     ;; Monkey-patch package-build so it doesn't shell out to git/hg.
+     (defun package-build--get-commit (&rest _)
+       commit)
      (package-build--package (package-recipe-lookup package) version))))