run app appargs fix for -- double-dash

src/pipx/main.py

@@ -573,12 +573,26 @@ def setup(args):
         )
 
 
+def parse_args(parser):
+    parsed_args = parser.parse_args()
+    if parsed_args.command == "run":
+        app_i = -(len(parsed_args.appargs) + 1)
+        # sys.argv[app_i] is:
+        #   app if no deleted "--" post-app in sys.argv
+        #   first item of appargs if "--" deleted post-app in sys.argv
+
+        # insert another "--" if first "--" is after app and no previous one
+        if "--" in sys.argv[app_i:] and "--" not in sys.argv[:app_i]:
+            sys.argv.insert(sys.argv.index("--", app_i), "--")
+    return parser.parse_args()
+
+
 def cli() -> int:
     """Entry point from command line"""
     try:
         parser = get_command_parser()
         argcomplete.autocomplete(parser)
-        parsed_pipx_args = parser.parse_args()
+        parsed_pipx_args = parse_args(parser)
         setup(parsed_pipx_args)
         if not parsed_pipx_args.command:
             parser.print_help()

tests/test_run.py

@@ -42,3 +42,24 @@ def test_run_script_from_internet(pipx_temp_env, capsys):
             "6bdfbb6e9c1132b1c38fdd2f195d4a24c540c324/pipx-demo.py",
         ]
     )
+
+
+def test_appargs_doubledash(capsys):
+    run_pipx_cli(["run", "pycowsay", "--", "hello"])
+    captured = capsys.readouterr()
+    assert "< -- hello >" not in captured.out
+    run_pipx_cli(["run", "pycowsay", "hello", "--"])
+    captured = capsys.readouterr()
+    assert "< hello -- >" not in captured.out
+    run_pipx_cli(["run", "pycowsay", "--"])
+    captured = capsys.readouterr()
+    assert "< -- >" not in captured.out
+    run_pipx_cli(["run", "--", "pycowsay", "--", "hello"])
+    captured = capsys.readouterr()
+    assert "< -- hello >" not in captured.out
+    run_pipx_cli(["run", "--", "pycowsay", "hello", "--"])
+    captured = capsys.readouterr()
+    assert "< hello -- >" not in captured.out
+    run_pipx_cli(["run", "--", "pycowsay", "--"])
+    captured = capsys.readouterr()
+    assert "< -- >" not in captured.out