Inline ini comments are parsed along value

[Medhy DOHOU]

During my usage of cloudbase-init (https://github.com/cloudbase/cloudbase-init), I encountered a bug, where oslo.config would parse the value of the setting, alongside with the inline comment.

2022-11-25 15:25:18.360 1820 ERROR cloudbaseinit.init [-] plugin 'SetUserPasswordPlugin' failed with error 'Value for option inject_user_password from LocationInfo(location=<Locations.user: (4, True)>, detail='C:\\Program Files\\Cloudbase Solutions\\Cloudbase-Init\\conf\\cloudbase-init.conf') is not valid: Unexpected boolean value 'True # Use password from the metadata (not random).'': oslo_config.cfg.ConfigFileValueError: Value for option inject_user_password from LocationInfo(location=<Locations.user: (4, True)>, detail='C:\\Program Files\\Cloudbase Solutions\\Cloudbase-Init\\conf\\cloudbase-init.conf') is not valid: Unexpected boolean value 'True # Use password from the metadata (not random).'
2022-11-25 15:25:18.439 1820 ERROR cloudbaseinit.init [-] Value for option inject_user_password from LocationInfo(location=<Locations.user: (4, True)>, detail='C:\\Program Files\\Cloudbase Solutions\\Cloudbase-Init\\conf\\cloudbase-init.conf') is not valid: Unexpected boolean value 'True # Use password from the metadata (not random).': oslo_config.cfg.ConfigFileValueError: Value for option inject_user_password from LocationInfo(location=<Locations.user: (4, True)>, detail='C:\\Program Files\\Cloudbase Solutions\\Cloudbase-Init\\conf\\cloudbase-init.conf') is not valid: Unexpected boolean value 'True # Use password from the metadata (not random).'
2022-11-25 15:25:18.439 1820 ERROR cloudbaseinit.init Traceback (most recent call last):
2022-11-25 15:25:18.439 1820 ERROR cloudbaseinit.init File "C:\Program Files\Cloudbase Solutions\Cloudbase-Init\Python\lib\site-packages\oslo_config\cfg.py", line 2694, in _do_get
2022-11-25 15:25:18.439 1820 ERROR cloudbaseinit.init return (convert(val), alt_loc)
2022-11-25 15:25:18.439 1820 ERROR cloudbaseinit.init File "C:\Program Files\Cloudbase Solutions\Cloudbase-Init\Python\lib\site-packages\oslo_config\cfg.py", line 2664, in convert
2022-11-25 15:25:18.439 1820 ERROR cloudbaseinit.init self._substitute(value, group, namespace), opt)
2022-11-25 15:25:18.439 1820 ERROR cloudbaseinit.init File "C:\Program Files\Cloudbase Solutions\Cloudbase-Init\Python\lib\site-packages\oslo_config\cfg.py", line 2791, in _convert_value
2022-11-25 15:25:18.439 1820 ERROR cloudbaseinit.init return opt.type(value)
2022-11-25 15:25:18.439 1820 ERROR cloudbaseinit.init File "C:\Program Files\Cloudbase Solutions\Cloudbase-Init\Python\lib\site-packages\oslo_config\types.py", line 250, in __call__
2022-11-25 15:25:18.439 1820 ERROR cloudbaseinit.init raise ValueError('Unexpected boolean value %r' % value)

Although INI files don't have a defined specification or RFC, I think inline comments are valuable, and the library could benefit from them.

I am willing to create a fix for that, if necessary.

[Takashi Kajinami (kajinamit)]

I don't think inline comment support is such common. For example configparser in python does not support it either.

$ cat test.ini
[foo]
key1=val1
key2=val2 # comment
$ python
Python 3.11.7 (main, Dec 18 2023, 00:00:00) [GCC 13.2.1 20231011 (Red Hat 13.2.1-4)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import configparser
>>> parser = configparser.ConfigParser()
>>> parser.read('test.ini')
['test.ini']
>>> parser.sections()
['foo']
>>> parser['foo']
<Section: foo>
>>> parser['foo']['key1']
'val1'
>>> parser['foo']['key2']
'val2 # comment'
>>>

Users can put comments in separate lines.

[Takashi Kajinami (kajinamit)]

crudini, which is another common tool to parse ini file, does not support inline comments.

$ crudini --get test.ini foo key1
val1
$ crudini --get test.ini foo key2
val2 # comment

[Takashi Kajinami (kajinamit)]

Based on the fact this is not supported in common tools/libraries I'm closing this RFE.
I don't think adding that uncommon support does not bring much benefit (because users can use the legit alternative approach) while it can bring different problems (for example when a value actually need to contain #).