Allow non-integer exit codes (#5721)

* Allow non-integer exit codes justl like in Python proper

* doc: add news item

* Update fr-exit-str.rst

---------

Co-authored-by: Andy Kipp <anki-code@users.noreply.github.com>

news/fr-exit-str.rst

@@ -0,0 +1,23 @@
+**Added:**
+
+* <news item>
+
+**Changed:**
+
+* <news item>
+
+**Deprecated:**
+
+* <news item>
+
+**Removed:**
+
+* <news item>
+
+**Fixed:**
+
+* Fixed non-int sys.exit codes raising ValueError.
+
+**Security:**
+
+* <news item>

xonsh/main.py

@@ -606,7 +606,14 @@ def main_xonsh(args):
             err_type, err, _ = exc_info
             if err_type is SystemExit:
                 code = getattr(exc_info[1], "code", 0)
-                exit_code = int(code) if code is not None else 0
+                if code is None:
+                    exit_code = 0
+                else:
+                    exit_code = code
+                    try:
+                        exit_code = int(code)
+                    except ValueError:
+                        pass
                 XSH.exit = exit_code
             else:
                 exit_code = 1