debuglock: make the command more useful in non-interactive mode

The existing prompt mode simply release the lock immediately in non-interactive
mode.  That is quite useless in the test so now the non-interactive mode simply
wait for a signal.

Differential Revision: https://phab.mercurial-scm.org/D12616

mercurial/debugcommands.py

@@ -2201,7 +2201,19 b' def debuglocks(ui, repo, **opts):'
             except error.LockHeld:
                 raise error.Abort(_(b'lock is already held'))
         if len(locks):
-            ui.promptchoice(_(b"ready to release the lock (y)? $$ &Yes"))
+            try:
+                if ui.interactive():
+                    prompt = _(b"ready to release the lock (y)? $$ &Yes")
+                    ui.promptchoice(prompt)
+                else:
+                    msg = b"%d locks held, waiting for signal\n"
+                    msg %= len(locks)
+                    ui.status(msg)
+                    while True:  # XXX wait for a signal
+                        time.sleep(0.1)
+            except KeyboardInterrupt:
+                msg = b"signal-received releasing locks\n"
+                ui.status(msg)
             return 0
     finally:
         release(*locks)