Use mutex group for --args|cmd and fix cmd to use a list type.

Author: fritzr

gdbgui/backend.py

@@ -761,6 +761,7 @@ def main():
     parser = argparse.ArgumentParser(description=__doc__)
 
     gdb_group = parser.add_argument_group(title="gdb commands")
+    args_group = parser.add_mutually_exclusive_group()
     network = parser.add_argument_group(title="gdbgui network settings")
     security = parser.add_argument_group(title="security settings")
     other = parser.add_argument_group(title="other settings")
@@ -853,22 +854,23 @@ def main():
         action="store_true",
     )
 
-    gdb_group.add_argument(
+    args_group.add_argument(
+        "cmd",
+        nargs='?',
+        type=lambda prog : [prog],
+        help='Name of the binary to run in gdb. To pass flags to the binary,'
+            ' use --args instead.'
+            ' Example: gdbgui ./mybinary [gdbgui-args...]',
+        default=[],
+    )
+    args_group.add_argument(
         "--args",
         nargs=argparse.REMAINDER,
         help='All remaining args are taken as the binary and arguments to run'
             ' in gdb (as with gdb --args).'
             ' Example: gdbgui [...] --args ./mybinary myarg -flag1 -flag2',
         default=[],
     )
-    gdb_group.add_argument(
-        "cmd",
-        nargs='?',
-        help='Name of the binary to run in gdb. To pass flags to the binary,'
-            ' use --args.'
-            ' Example: gdbgui ./mybinary [gdbgui-args...]',
-        default=[],
-    )
 
     args = parser.parse_args()
 
@@ -878,13 +880,7 @@ def main():
         print(__version__)
         return
 
-    if args.cmd and args.args:
-        print("Cannot specify command and args. Must specify one or the other.")
-        exit(1)
-    if args.cmd:
-        cmd = args.cmd
-    else:
-        cmd = args.args
+    cmd = args.cmd or args.args
 
     app.config["initial_binary_and_args"] = cmd
     app.config["rr"] = args.rr