From b4e4982e6ce36281159e2256a936f302bda1eb5c Mon Sep 17 00:00:00 2001
From: Tad Fisher <tadfisher@gmail.com>
Date: Mon, 23 May 2022 12:52:17 -0700
Subject: [PATCH] emacsPackages.melpaBuild: Update package-build, avoid
 monkey-patch

---
 pkgs/build-support/emacs/melpa.nix    |  4 ++--
 pkgs/build-support/emacs/melpa2nix.el | 18 ++++++++++++++----
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/pkgs/build-support/emacs/melpa.nix b/pkgs/build-support/emacs/melpa.nix
index 408448f26a0e..924e6d95f14a 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 gcc; } ({
   packageBuild = fetchFromGitHub {
     owner = "melpa";
     repo = "package-build";
-    rev = "047801d301a73d4932f33f768d94a8ed26b8d524";
-    sha256 = "0ygzkpg7xc3mjjbxg1kcyz6fwbkb0prvca499f0ffmhfaiv28h59";
+    rev = "35017a2d87376c70c3239f48bdbac7efca85aa10";
+    sha256 = "07hdmam85452v4r2vaabj1qfyami1hgbh0jgj9dcwbkpr0y1gvqj";
   };
 
   elpa2nix = ./elpa2nix.el;
diff --git a/pkgs/build-support/emacs/melpa2nix.el b/pkgs/build-support/emacs/melpa2nix.el
index 383423af0818..72667dea652c 100644
--- a/pkgs/build-support/emacs/melpa2nix.el
+++ b/pkgs/build-support/emacs/melpa2nix.el
@@ -11,12 +11,22 @@
 ;; Allow installing package tarfiles larger than 10MB
 (setq large-file-warning-threshold nil)
 
+(defun melpa2nix-build-package-1 (rcp version commit)
+  (let ((source-dir (package-recipe--working-tree rcp)))
+    (unwind-protect
+        (let ((files (package-build-expand-files-spec rcp t)))
+          (cond
+           ((= (length files) 1)
+            (package-build--build-single-file-package
+             rcp version commit files source-dir))
+           ((> (length files) 1)
+            (package-build--build-multi-file-package
+             rcp version commit files source-dir))
+           (t (error "Unable to find files matching recipe patterns")))))))
+
 (defun melpa2nix-build-package ()
   (if (not noninteractive)
       (error "`melpa2nix-build-package' is to be used only with -batch"))
   (pcase command-line-args-left
     (`(,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))))
+     (melpa2nix-build-package-1 (package-recipe-lookup package) version commit))))