[Python-projects] Using plugins, options and .pylintrc crashes PyLint

[Dore Laurent]

Hi,

I am trying to create a plugin that declares its own options for use
with the .pylintrc file.
This only works when the plugin is auto-loaded from the pylint.checkers
package.
When the plugin is outside pylint.checkers (given by .pylintrc's
load-plugins), I get the traceback:

Traceback (most recent call last):
  File "D:\Apps\Python26\lib\runpy.py", line 121, in _run_module_as_main
    "__main__", fname, loader, pkg_name)
  File "D:\Apps\Python26\lib\runpy.py", line 34, in _run_code
    exec code in run_globals
  File
"D:\Apps\Python26\lib\site-packages\pylint-0.18.0-py2.6.egg\pylint\lint.
py", line 932, in <module>
    Run(sys.argv[1:])
  File
"D:\Apps\Python26\lib\site-packages\pylint-0.18.0-py2.6.egg\pylint\lint.
py", line 854, in __init__
    linter.load_plugin_modules(plugins)
  File
"D:\Apps\Python26\lib\site-packages\pylint-0.18.0-py2.6.egg\pylint\lint.
py", line 300, in load_plugin_modules
    module.register(self)
  File "custom.py", line 15, in register
    linter.register_checker(CustomChecker(linter))
  File
"D:\Apps\Python26\lib\site-packages\pylint-0.18.0-py2.6.egg\pylint\lint.
py", line 346, in register_checker
    self.register_options_provider(checker)
  File
"d:\apps\python26\lib\site-packages\logilab_common-0.39.0-py2.6.egg\logi
lab\common\configuration.py", line 385, in register_options_provider
    non_group_spec_options, provider)
  File
"d:\apps\python26\lib\site-packages\logilab_common-0.39.0-py2.6.egg\logi
lab\common\configuration.py", line 403, in add_option_group
    self._config_parser.add_section(group_name)
  File "D:\Apps\Python26\lib\ConfigParser.py", line 245, in add_section
    raise DuplicateSectionError(section)
ConfigParser.DuplicateSectionError: Section 'CUSTOMCHECK' already exists
 
 
To recreate this configuration:
1. Create the module custom.py, in a package other than pylint.checkers
 
2. In this module, declare a checker with custom options:
from pylint.checkers import BaseChecker
from pylint.interfaces import IASTNGChecker
class CustomChecker(BaseChecker):
    __implements__ = IASTNGChecker
    name = 'customcheck'
    priority = -1
    options = ( ('custom', 
                 {'default': ('value', ), 
                  'type': 'csv', 
                  'metavar': '<attributes>', 
                  'help': 'Custom option' }), )
 
def register(linter):
    print 'Registering custom checker'
    linter.register_checker(CustomChecker(linter)) 

3. Create a custom.pylintrc file, that uses, loads and declares the
checker's section:
[MASTER]
load-plugins=custom
[MESSAGE CONTROL]
enable-checker=customcheck
[CUSTOMCHECK]
custom=v1,v2
 
4. Launch PyLint:
python -m pylint.lint --rcfile=custom.pylintrc custom.py
... Crash
 
Analysis:
This happens because, in lint.py, class Run, method __init__:
a. Internal plugins are loaded (using
linter.load_plugin_modules(self._plugins)
b. The .pylintrc file is loaded (using linter.read_config_file(), this
overrides already declared contents)
c. External plugins are loaded (using
linter.load_plugin_modules(plugins)).
   This last step fails, as logilab-common is trying to (re-)add a
section that already exists in the config file, loaded in b.

Regards,

Laurent DORE