Fix issue #13817: Fixed ``AttributeError`` in ``Argument.__repr__`` when ``dest`` attribute is not set.

[thartline35]

Description

Fixes #13817

When an invalid option name is provided to pytest_addoption() (e.g., missing the -- prefix), pytest correctly detects the error but then fails while trying to display the error message. This results in an AttributeError that obscures the original, helpful validation error.

Root Cause

The Argument.__repr__() method unconditionally accesses self.dest, which hasn't been set yet when initialization is interrupted by a validation error in _set_opt_strings().

The Fix

Added a defensive hasattr() check for dest in __repr__, following the same pattern already used for the type and default attributes.

Before

AttributeError: 'Argument' object has no attribute 'dest'

After

ArgumentError: invalid long option string 'shuffle': must start with --, followed by non-dash

Changes

• Modified src/_pytest/config/argparsing.py: Added hasattr() check for dest attribute
• Added comprehensive test cases in testing/test_argparsing_repr_fix.py
• Added changelog entry
• Updated AUTHORS

All tests pass locally.