From 155bac1a455eb884d0cf8496433fd79f4578007a Mon Sep 17 00:00:00 2001
From: Robert Stupp <snazy@snazy.de>
Date: Wed, 15 Oct 2025 19:16:29 +0200
Subject: [PATCH] Reproducible builds: use a fixed mtime for all entries in the
 source tarball

This change makes generated source-tarballs binary-comparable, so that locally built one (via `./gradlew sourceTarball`) should be exactly the same as a staged one.
---
 build-logic/src/main/kotlin/publishing/rootProject.kt | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/build-logic/src/main/kotlin/publishing/rootProject.kt b/build-logic/src/main/kotlin/publishing/rootProject.kt
index 663d3a26d8..001d9ccee7 100644
--- a/build-logic/src/main/kotlin/publishing/rootProject.kt
+++ b/build-logic/src/main/kotlin/publishing/rootProject.kt
@@ -55,6 +55,8 @@ internal fun configureOnRootProject(project: Project) =
         "archive",
         "--prefix=${e.baseName.get()}/",
         "--format=tar.gz",
+        // use a fixed mtime for reproducible tarballs, using the same timestamp as jars do
+        "--mtime=1980-02-01 00:00:00",
         "--output=${e.sourceTarball.get().asFile.relativeTo(projectDir)}",
         "HEAD",
       )