fix(xcat-core): do not add a second syncfiles when the node already defers it

A node may list syncfiles in both postscripts and postbootscripts -- once for the install and
once for the booted node. The deferral prepended its own copy regardless, so the booted node ran
syncfiles twice in a row inside a marker block that made it look like xCAT had generated the
duplicate.

Keep the entry the node already has and still remove the install-time one, which is the copy
that cannot work in the in-target chroot.

Signed-off-by: Daniel Hilst <392820+dhilst@users.noreply.github.com>

xCAT-server/lib/perl/xCAT/Postage.pm

@@ -214,6 +214,11 @@ sub defer_syncfiles_to_postboot {
       unless defined($postscripts) && $postscripts =~ s/^[ \t]*syncfiles[ \t]*\n//m;
 
     $postbootscripts = "" unless defined $postbootscripts;
+
+    # A node may already list syncfiles as a postbootscript of its own; do not add a second copy.
+    return ($postscripts, $postbootscripts)
+      if $postbootscripts =~ /^[ \t]*syncfiles[ \t]*$/m;
+
     $postbootscripts =
         "# ubuntu-deferred-postbootscripts-start-here\nsyncfiles\n# ubuntu-deferred-postbootscripts-end-here\n"
       . $postbootscripts;

xCAT-test/unit/postage_ubuntu_syncfiles_postboot.t

@@ -83,6 +83,16 @@ foreach my $case (@untouched) {
     is($postboot, $DEFERRED, 'an undefined postbootscripts list becomes the deferral block');
 }
 
+# A node that already lists syncfiles as its own postbootscript keeps that entry, and does not
+# gain a second one -- the install-time copy is still removed, since that is the one that cannot work.
+{
+    my ($post, $postboot) =
+      defer('ubuntu24.04', 'install', 'install', "syncfiles\nfoo\n", "syncfiles\nsetupntp\n");
+    is($post, "foo\n", 'the postscripts entry is still removed');
+    is($postboot, "syncfiles\nsetupntp\n",
+        "an admin's own syncfiles postbootscript is left as it was, not duplicated");
+}
+
 # Rendering the same node twice must not stack a second copy.
 {
     my ($post, $postboot) =