From 6c5210a94f8b0ac89a1e97080a4e5d207468da8a Mon Sep 17 00:00:00 2001
From: Johannes Schauer Marin Rodrigues <josch@mister-muffin.de>
Date: Thu, 22 Dec 2022 10:17:40 +0100
Subject: [PATCH] error out early if setup fails and thus the ext2 block reader
 returns EOF

---
 mmdebstrap | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/mmdebstrap b/mmdebstrap
index 0f88582..f7f393b 100755
--- a/mmdebstrap
+++ b/mmdebstrap
@@ -5920,7 +5920,13 @@ sub main() {
     my $numblocks = 0;
     close $nblkwriter;
     if (!$options->{dryrun} && $format eq 'ext2') {
-        chomp($numblocks = <$nblkreader>);
+        $numblocks = <$nblkreader>;
+        if (!defined $numblocks) {
+            # This can happen if the setup process died early and thus closes
+            # the pipe from the other and. The EOF is turned into undef.
+            error "failed to read required number of blocks";
+        }
+        chomp $numblocks;
     }
     close $nblkreader;