CI Error AttributeError: 'ExcelFile' object has no attribute 'engine'

[WillAyd]

Showing up in

https://dev.azure.com/pandas-dev/pandas/_build/results?buildId=22986&view=logs

Traceback (most recent call last):
  File "D:\a\1\s\pandas\io\excel\_base.py", line 907, in __del__
    self.close()
  File "D:\a\1\s\pandas\io\excel\_base.py", line 890, in close
    if self.engine == "openpyxl":
AttributeError: 'ExcelFile' object has no attribute 'engine'

Looks to be caused by changes in #30096 - I think need to make it self.reader.engine. But definitely shows this code getting hit

@jbrockmendel

[jbrockmendel]

yah, ive been seeing that locally ocassionally. last time i looked at it i concluded that self.engine is correct, and best guess is that since this is happening inside __del__, something weird is going on with __dict__ getting cleared out. Hopefully I'm wrong on this and changing self.engine -> self.reader.engine fixes it.

[WillAyd]

Hmm actually that's a good point. I misread that engine was never an attribute of the ExcelFile but that's not true

[jorisvandenbossche]

I think the code in the __del__ function can be wrapped in a try / except to hide those errors. When python is cleaning up, you are not exactly sure about the order, so certain variables that are accessed in the __del__ method can already be deleted before the parent object is (see warning box at https://docs.python.org/3/reference/datamodel.html#object.__del__)