lei_mirror: don't clobber inbox.config.example if it exists

Users may save notes or edits in there, and it's only an
example, so there's no need to mindlessly clobber it.

1 files changed, 9 insertions, 6 deletions

diff --git a/lib/PublicInbox/LeiMirror.pm b/lib/PublicInbox/LeiMirror.pm
index e284f55d..04e54955 100644
--- a/lib/PublicInbox/LeiMirror.pm
+++ b/lib/PublicInbox/LeiMirror.pm
@@ -181,13 +181,16 @@ sub _write_inbox_config {
         my $buf = delete($self->{'txt._/text/config/raw'}) // return;
         my $dst = $self->{cur_dst} // $self->{dst};
         my $f = "$dst/inbox.config.example";
-        open my $fh, '>', $f or die "open($f): $!";
-        print $fh $buf or die "print: $!";
-        chmod(0444 & ~umask, $fh) or die "chmod($f): $!";
         my $mtime = delete $self->{'mtime._/text/config/raw'};
-        $fh->flush or die "flush($f): $!";
-        if (defined $mtime) {
-                utime($mtime, $mtime, $fh) or die "utime($f): $!";
+        if (sysopen(my $fh, $f, O_CREAT|O_EXCL|O_WRONLY)) {
+                print $fh $buf or die "print: $!";
+                chmod(0444 & ~umask, $fh) or die "chmod($f): $!";
+                $fh->flush or die "flush($f): $!";
+                if (defined $mtime) {
+                        utime($mtime, $mtime, $fh) or die "utime($f): $!";
+                }
+        } elsif (!$!{EEXIST}) {
+                die "open($f): $!";
         }
         my $cfg = PublicInbox::Config->git_config_dump($f, $self->{lei}->{2});
         my $ibx = $self->{ibx} = {};