Hey there! That's a quirky IDLE bug you've run into—let's break down what's happening and how to fix it.

What's Causing the Issue? #

IDLE's auto-indentation engine has a weird glitch when it encounters the special __file__ variable inside class methods. It misinterprets the line self.directory = os.path.abspath(os.path.dirname(__file__)) as an unfinished syntax structure, which is why it shoves the next line's indent way to the right. This isn't a Python syntax error—the code itself is totally valid—just an editor parsing bug that sticks around across both Python 2.x and 3.x versions of IDLE.

Quick Fixes to Bypass the Bug #

Here are a few simple workarounds to get IDLE's auto-indent behaving normally again:

• Split the line into two steps: Break the path calculation into separate assignments. This avoids triggering IDLE's broken parser logic:

  # Split path calculation to avoid IDLE's indent bug
  module_dir = os.path.dirname(__file__)
  self.directory = os.path.abspath(module_dir)
  

• Add extra parentheses around __file__: Sometimes extra grouping helps IDLE parse the line correctly:

  self.directory = os.path.abspath(os.path.dirname((__file__)))
  

• Temporarily disable auto-indent: If you just need to wrap up writing the code quickly, you can turn off auto-indent in IDLE via Options > Configure IDLE > Editor and uncheck "Auto-indent". Don't forget to toggle it back on later if you like using it!

Why Does Commenting Out the Line Fix It? #

When you comment out that line, IDLE no longer encounters __file__ in that specific context, so its parser goes back to normal indentation behavior. The root issue is 100% with IDLE's syntax parsing, not your code's validity.

内容的提问来源于stack exchange，提问作者Pr Mod