[PATCH 1/1] Strip parent path from package descriptions for reproducibility

[Rob Browning <rlb@defaultvalue.org>]

Previously, the package description would include the full build tree
path which varies.  Instead, remove any duplicate slashes and any
components other than the immediate parent.

Bug-Debian: https://bugs.debian.org/972861
---

 I'm not sure this is suitable for Emacs proper, and it could likely
 use some improvement, but we've applied it in Debian for the time
 being in order to avoid introducing unreprodcible strings into
 generated packages.

 lisp/emacs-lisp/package.el | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lisp/emacs-lisp/package.el b/lisp/emacs-lisp/package.el
index 7d6be3cf4e2..60561fdb678 100644
--- a/lisp/emacs-lisp/package.el
+++ b/lisp/emacs-lisp/package.el
@@ -963,7 +963,11 @@ package-generate-description-file
       (write-region
        (concat
         ";;; Generated package description from "
-        (replace-regexp-in-string "-pkg\\.el\\'" ".el" pkg-file)
+        (replace-regexp-in-string ;; just the final y.el or x/y.el
+         "^.*?\\([^/]+/\\)?\\([^/]+\\)$" "\\1\\2"
+         (replace-regexp-in-string
+          "/+" "/"
+          (replace-regexp-in-string "-pkg\\.el\\'" ".el" pkg-file)))
         "  -*- no-byte-compile: t -*-\n"
         (prin1-to-string
          (nconc
-- 
2.29.2