Using Inline to [re]define default fields causes "maximum recursion depth exceeded"

[RollingStar]

Problem

Another semi-silly one. Users can probably guess that this is a bad idea, but I tried it anyway.

This happens after telling import to [R]emove old:

[many more lines like the following]
  File "beets\beetsplug\inline.py", line 102, in _dict_for
    out = dict(obj)
  File "beets\beets\dbcore\db.py", line 237, in __getitem__
    return getters[key](self)
  File "beets\beetsplug\inline.py", line 120, in _func_func
    func.__globals__.update(_dict_for(obj))
  File "beets\beetsplug\inline.py", line 102, in _dict_for
    out = dict(obj)
  File "beets\beets\dbcore\db.py", line 237, in __getitem__
    return getters[key](self)
  File "beets\beetsplug\inline.py", line 120, in _func_func
    func.__globals__.update(_dict_for(obj))
  File "beets\beetsplug\inline.py", line 102, in _dict_for
    out = dict(obj)
  File "beets\beets\dbcore\db.py", line 281, in keys
    base_keys = list(self._fields) + list(self._values_flex.keys())
RecursionError: maximum recursion depth exceeded while calling a Python object

Led to this problem:

album_fields:
   album: |
        return 'asdf'

Setup

• OS: Win10 x64 Powershell
• Python version: 3.6.0
• beets version: 1.4.4+ (git intermediate before 1.4.5)
• Turning off plugins made problem go away (yes/no): probably

When I have beets like this, it lists two "album" fields in beet fields.

Potential fix

Maybe quit beets with an error message about using the same fields as beets defaults?

[sampsyo]

Thanks! That's a pretty clear problem: to compute the value of album, beets is trying to use the value of album. 🙄 We may even be able to support this by cutting the recursion cycle.

[zhelezov]

Just stumbled upon this issue after trying the following:

item_fields:
    original_year: original_year if original_year > 0 else year
album_fields:
    original_year: original_year if original_year > 0 else year

So, the only workaround to fix a missing value is adding a custom field?

[sampsyo]

Indeed; choosing a new name will work.

[jslpc]

Just a heads up, this also affects beet update. Had to disable the inline plugin entirely to get anything to work again.