init: preserve permissions of existing config file

This matches git-config(1) behavior, and implied user
intent when it comes to programatically editing files.

1 files changed, 8 insertions, 2 deletions

diff --git a/t/init.t b/t/init.t
index b78fbaf5..f87dc225 100644
--- a/t/init.t
+++ b/t/init.t
@@ -13,10 +13,16 @@ use constant pi_init => 'blib/script/public-inbox-init';
         my $cfgfile = "$ENV{PI_DIR}/config";
         my @cmd = (pi_init, 'blist', "$tmpdir/blist",
                    qw(http://example.com/blist blist@example.com));
-        is(system(@cmd), 0, 'public-inbox-init failed');
+        is(system(@cmd), 0, 'public-inbox-init OK');
 
         ok(-e $cfgfile, "config exists, now");
-        is(system(@cmd), 0, 'public-inbox-init failed (idempotent)');
+        is(system(@cmd), 0, 'public-inbox-init OK (idempotent)');
+
+        chmod 0666, $cfgfile or die "chmod failed: $!";
+        @cmd = (pi_init, 'clist', "$tmpdir/clist",
+                   qw(http://example.com/clist clist@example.com));
+        is(system(@cmd), 0, 'public-inbox-init clist OK');
+        is((stat($cfgfile))[2] & 07777, 0666, "permissions preserved");
 }
 
 done_testing();