ceph.in: reject -w/--watch flags when used with subcommands

parse_known_args() silently consumes -w and all --watch-* flags
before subcommand arguments reach the command validator. When a
user ran "ceph orch ps -w", the watch handler entered cluster log
streaming mode while discarding the subcommand entirely, with no
error or indication that the orch ps command was ignored.

Add a guard at the entry of the watch handler: if any watch flag
is active and childargs is non-empty, print "Invalid command:
unused arguments: [...]" and return EINVAL. This matches the
behaviour already seen when -s/--status is combined with a
subcommand.

Assisted-by: Claude:claude-4.6-sonnet
Fixes: https://tracker.ceph.com/issues/77121
Signed-off-by: Yonatan Zaken <yzaken@redhat.com>

diff --git a/src/ceph.in b/src/ceph.in
index 4694da29db5fea32f5f6e7986920b60037d710d1..3379de7488e9099620f714828d737ac5fc840473 100755 (executable)
--- a/src/ceph.in
+++ b/src/ceph.in
@@ -1131,6 +1131,9 @@ def main():
             elif k != "watch_channel":
                 level = k.replace('watch_', '')
     if level:
+        if childargs:
+            print('Invalid command: unused arguments: {0}'.format(childargs), file=sys.stderr)
+            return errno.EINVAL
         # an awfully simple callback
         def watch_cb(arg, line, channel, name, who, stamp_sec, stamp_nsec, seq, level, msg):
             # Filter on channel