[PATCH pit] bin/public-inbox-tg: Fix fatal error when "To:" or CC list is empty

[Alviro Iskandar Setiawan <alviro.iskandar@gnuweeb.org>]

When "To:" or CC list is empty, we don't have the $toList or $ccList
variable, we must always check their existence before entering the
array_merge() call. Fix it by using null coalescing operator and
fallback to an empty array.

Link: https://t.me/GNUWeeb/544137
Reported-by: Arthur Lapz <rlapz@gnuweeb.org>
Fixes: b7a968b53f42f7392ac2fb3450524bb4a949baab ("bin/public-inbox-tg: Add Telegram CC notification support")
Signed-off-by: Alviro Iskandar Setiawan <alviro.iskandar@gnuweeb.org>
---
 bin/public-inbox-tg.php | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/bin/public-inbox-tg.php b/bin/public-inbox-tg.php
index 61d4968..f17fffe 100644
--- a/bin/public-inbox-tg.php
+++ b/bin/public-inbox-tg.php
@@ -157,7 +157,10 @@ function fx(string $input): int
 	if ($ccListStr)
 		$msg .= "{$ccListStr}\n";
 
-	$tgCCs = array_merge(...[listTelegramLookup($toList), listTelegramLookup($ccList)]);
+	$tgCCs = array_merge(...[
+		listTelegramLookup($toList ?? []),
+		listTelegramLookup($ccList ?? [])
+	]);
 	$tgCCs = array_unique($tgCCs);
 
 	if (count($tgCCs) > 0)

base-commit: 48fc9b434d878691d11c77beab3fa459a337ce48
-- 
2.32.0