From: Dirk Eddelbuettel <edd@debian.org>
Date: Oct, 27 2026 18:39:30 -0500
Subject: [PATCH] <short summary of the patch>

The 'tools' package calls tools:::.installed_package_description in the 
two-argument form where as possible third argument 'timestamp' is not
passed down. So when 'SOURCE_DATE_EPOCH' is in fact set, use it.

--- r-base-4.6.1.orig/src/library/tools/Makefile.in
+++ r-base-4.6.1/src/library/tools/Makefile.in
@@ -45,8 +45,13 @@ all: Makefile DESCRIPTION
 	  fi \
 	fi
 	@$(MAKE) sysdata
-	@$(ECHO) "tools:::.install_package_description('.', '"$(top_builddir)/library/${pkg}"')" | \
-	  R_DEFAULT_PACKAGES=NULL $(R_EXE) > /dev/null
+	@if test "$(SOURCE_DATE_EPOCH)" != ""; then \
+	  $(ECHO) "tools:::.install_package_description('.', '"$(top_builddir)/library/${pkg}"', '"$(SOURCE_DATE_EPOCH)"')" | \
+	    R_DEFAULT_PACKAGES=NULL $(R_EXE) > /dev/null ; \
+	else \
+	  $(ECHO) "tools:::.install_package_description('.', '"$(top_builddir)/library/${pkg}"')" | \
+	    R_DEFAULT_PACKAGES=NULL $(R_EXE) > /dev/null ; \
+	fi
 
 mkR: mkR1
 
