From 38e8778d0f118a7e9f5cff29abb589364e7ba0ef Mon Sep 17 00:00:00 2001
From: Brennan Kinney <5098581+polarathene@users.noreply.github.com>
Date: Thu, 1 Aug 2024 13:42:44 +1200
Subject: [PATCH] fix: Prevent `stderr` being written to `/etc/postfix/main.cf`

`stderr` is filtered by `grep` to discard unwanted (expected) log noise when appending the override `postfix-main.cf` content (_updated settings did not replace earlier defined instances_).

That `grep` filter introduced a regression into DMS v14 release, since any other `stderr` content not being excluded was now blended into `stdout` and redirected with the original `stdout` output for the `postconf -n` command.

The fix is to ensure the `grep` output is redirect to `stderr` to avoid that mishap.
---
 target/scripts/startup/setup.d/postfix.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target/scripts/startup/setup.d/postfix.sh b/target/scripts/startup/setup.d/postfix.sh
index 3ebdeb9d..e140fbaa 100644
--- a/target/scripts/startup/setup.d/postfix.sh
+++ b/target/scripts/startup/setup.d/postfix.sh
@@ -129,7 +129,7 @@ function __postfix__setup_override_configuration() {
     # Do not directly output to 'main.cf' as this causes a read-write-conflict.
     # `postconf` output is filtered to skip expected warnings regarding overrides:
     # https://github.com/docker-mailserver/docker-mailserver/pull/3880#discussion_r1510414576
-    postconf -n >/tmp/postfix-main-new.cf 2> >(grep -v 'overriding earlier entry')
+    postconf -n >/tmp/postfix-main-new.cf 2> >(grep -v 'overriding earlier entry' >&2)
 
     mv /tmp/postfix-main-new.cf /etc/postfix/main.cf
     _adjust_mtime_for_postfix_maincf