From 993322f6d7cd68b8843f23fa0b3425fb86794c57 Mon Sep 17 00:00:00 2001
From: Luke Bakken <lrbakken@amazon.com>
Date: Wed, 27 Aug 2025 12:49:20 -0700
Subject: [PATCH] Ensure that file modified time is set correctly

Commit e435bc6886dfd9311d1c26e0ab615f8a62931215 introduced behavior in
creating the source-dist archive that sets the file modification time to
the same time as the most recent `git` commit. This facilitates
reproducible builds, but it also has an issue. The code sets `TZ=`,
which means that on systems running in time zones which aren't UTC, the
modification time may be in the future (or past). It depends on the
system's behavior.

Up until recently, this only resulted in GNU make printing warnings
about modification times being in the future. However, with recent
changes in how escripts are built, this results in an "infinite make
loop" that is described in https://github.com/rabbitmq/rabbitmq-server/discussions/14440
and https://github.com/rabbitmq/rabbitmq-server/discussions/14443

This solution is to set the `TZ=UTC` when calculating the time of the
most recent `git` commit, as well as when using `touch -t` to set the
file modification times.

Fixes #14440, #14443
---
 Makefile | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/Makefile b/Makefile
index 842c51b282..d8636dd4b5 100644
--- a/Makefile
+++ b/Makefile
@@ -189,7 +189,7 @@ $(1): $(ERLANG_MK_RECURSIVE_DEPS_LIST)
 	$${gen_verbose} $${RSYNC} $(2) ./ $$@/
 	$${verbose} echo "$(PROJECT_DESCRIPTION) $(PROJECT_VERSION)" > $$@/git-revisions.txt
 	$${verbose} echo "$(PROJECT) $$$$(git rev-parse HEAD) $$$$(git describe --tags --exact-match 2>/dev/null || git symbolic-ref -q --short HEAD)" >> $$@/git-revisions.txt
-	$${verbose} echo "$$$$(TZ= git --no-pager log -n 1 --format='%cd' --date='format-local:%Y%m%d%H%M.%S')" > $$@.git-times.txt
+	$${verbose} echo "$$$$(TZ=UTC git --no-pager log -n 1 --format='%cd' --date='format-local:%Y%m%d%H%M.%S')" > $$@.git-times.txt
 	$${verbose} cat packaging/common/LICENSE.head > $$@/LICENSE
 	$${verbose} mkdir -p $$@/deps/licensing
 	$${verbose} set -e; for dep in $$$$(cat $(ERLANG_MK_RECURSIVE_DEPS_LIST) | LC_COLLATE=C sort); do \
@@ -216,8 +216,7 @@ $(1): $(ERLANG_MK_RECURSIVE_DEPS_LIST)
 		 echo "$$$$(basename "$$$$dep") $$$$(git rev-parse HEAD) $$$$(git describe --tags --exact-match 2>/dev/null || git symbolic-ref -q --short HEAD)") \
 		 >> "$$@/git-revisions.txt"; \
 		! test -d $$$$dep/.git || (cd $$$$dep; \
-		 echo "$$$$(env TZ= git --no-pager log -n 1 --format='%cd' --date='format-local:%Y%m%d%H%M.%S')") \
-		 >> "$$@.git-times.txt"; \
+		 echo "$$$$(TZ=UTC git --no-pager log -n 1 --format='%cd' --date='format-local:%Y%m%d%H%M.%S')") >> "$$@.git-times.txt"; \
 	done
 	$${verbose} cat packaging/common/LICENSE.tail >> $$@/LICENSE
 	$${verbose} find $$@/deps/licensing -name 'LICENSE-*' -exec cp '{}' $$@ \;
@@ -231,7 +230,7 @@ $(1): $(ERLANG_MK_RECURSIVE_DEPS_LIST)
 	done
 	$${verbose} echo "PLUGINS := $(PLUGINS)" > $$@/plugins.mk
 	$${verbose} sort -r < "$$@.git-times.txt" | head -n 1 > "$$@.git-time.txt"
-	$${verbose} find $$@ -print0 | xargs -0 touch -t "$$$$(cat $$@.git-time.txt)"
+	$${verbose} find $$@ -print0 | (TZ=UTC xargs -0 touch -t "$$$$(cat $$@.git-time.txt)")
 	$${verbose} rm "$$@.git-times.txt" "$$@.git-time.txt"
 
 $(1).manifest: $(1)