From 12024d0faddfd49d0da7644ea231772bcb128869 Mon Sep 17 00:00:00 2001
From: Dan Rostovtsev <dan@rostovtsev.org>
Date: Sun, 5 Apr 2026 17:17:07 -0400
Subject: Zeroing in on rocq diff:

* reproduce.bash: using guix build / gc to get two isolated build results
* build-and-diff.scm: removed.

Change-Id: I4de1ee1bdd769bf2030b173ff454be0179ca82d7
---
 build-and-diff.scm | 31 -------------------------------
 reproduce.bash     | 45 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+), 31 deletions(-)
 delete mode 100644 build-and-diff.scm
 create mode 100644 reproduce.bash

diff --git a/build-and-diff.scm b/build-and-diff.scm
deleted file mode 100644
index 39e164e9e3a..00000000000
--- a/build-and-diff.scm
+++ /dev/null
@@ -1,31 +0,0 @@
-;; build-and-diff a derivation run twice.
-(use-modules (guix packages)
-             (guix store)
-             (guix derivations)
-             (gnu packages))
-
-(define (get-package-name) (read))
-
-(define (run-derivation-and-save pkgname outdir tag)
-  (let* ((pkg (specification->package pkgname))
-         (store (open-connection))
-         (drv ((package->derivation pkg) store))
-         (output (derivation->output-path drv))
-         (dest (string-append outdir "/" tag)))
-    (if (not (file-exists? outdir)) (mkdir outdir))
-    (build-derivations store (list drv))
-    (system* "chmod" "-R" "u+w" outdir)
-    (system* "rm" "-rf" dest)
-    (system* "cp" "-r" "-L" output dest)
-    dest))
-
-(let* ((pkgname (get-package-name))
-       (outdir (string-append "diff-build-" pkgname))
-       (tags '("a" "b")))
-  (write
-   (map
-    (lambda (tag)
-      (cons tag
-            (run-derivation-and-save pkgname outdir tag)))
-    tags))
-  (newline))
diff --git a/reproduce.bash b/reproduce.bash
new file mode 100644
index 00000000000..cb2f6993c9b
--- /dev/null
+++ b/reproduce.bash
@@ -0,0 +1,45 @@
+# a tool to reproduce a build for checking diffs
+
+while getopts :p: OPT; do
+    case $OPT in
+	p|+p)
+	    PACKAGE=$OPTARG
+	    ;;
+	*)
+	    echo "usage: ${0##*/} [+-p ARG} [--] ARGS..."
+	    exit 2
+    esac
+done
+shift $(( OPTIND - 1 ))
+OPTIND=1
+
+if [ ! $PACKAGE ]
+then
+    echo "Please set package with -p"
+    exit 1
+fi
+
+function reproduce-and-tag
+{
+    TAG=$1
+    OUT=$(guix build --no-substitutes $PACKAGE)
+    REPRODIR=repro/$PACKAGE/$TAG
+    mkdir -p $REPRODIR
+    cp -r $OUT/* $REPRODIR
+    chmod -R u+w $REPRODIR # default not writeable in store
+    guix gc -D $OUT
+    if [ -f $OUT ]
+    then
+	echo [ERROR] $OUT was not deleted
+	exit 1
+    fi
+    echo "=== REPRODUCTION SUMMARY ==="
+    echo "Tag: $TAG"
+    echo "Store Output: $OUT"
+    echo "Copied to: $REPRODIR"
+    echo "----------------------------"
+    echo
+}
+
+reproduce-and-tag "A"
+reproduce-and-tag "B"
-- 
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