Nucop

This gem contains custom cops and additional tooling for Nulogy's implementation of RuboCop.

This functionality is executed by the bin/nucop executable. If you installed the gem, it will be added to your path.

Purpose

When integrating RuboCop into large existing project, it is likely that it will have an overwhelming number of offenses. To aid adoption, RuboCop can generate a .rubocop_todo.yml file to exclude existing violations.

This presents two problems:

• It is harder for developers to fix existing problems, since TODO violations are ignored
• Cops with too many violations are disabled, so new violations can be introduced into the codebase

Editors can help with the former. However, nucop provides a couple tools to help speed adoption:

1. Enforced cops

This is a new list of cops and/or departments that MUST not have violations.

This is useful in CI if you do not want developers to add new Layout/ violations, etc.

Also, if nucop regen_backlog is used to regenerate the TODO file, any cops that had TODO violations, but no longer have violations are automatically added to enforced cops list.

2. nucop modified_lines

This command will print ALL RuboCop violations (i.e. including TODO violations) for all code lines changes since some git SHA.

This can be useful for local development, to increases visibility of existing violations during development cycles, but does not hold up code in CI.

Finally, several custom cops are included, which may be application/framework/gem specific.

CLI Commands

The nucop CLI provides the following commands:

Command	Description
diff_enforced	run RuboCop on the current diff using only the enforced cops
diff_enforced_github	run RuboCop on the current diff using only the enforced cops (uses GitHub to determine the current diff)
diff	run RuboCop on the current diff
diff_github	run RuboCop on the current diff (uses GitHub to determine the current diff)
rubocop	run RuboCop on files provided (without backlog by default)
regen_backlog	update the RuboCop backlog, updating enforced cops list
update_enforced	update the enforced cops list with file with cops that no longer have violations
modified_lines	display RuboCop violations for ONLY modified lines
ready_for_promotion	display the next n cops with the fewest violations

Requirements

Beyond a working Ruby installation and what is specified in the gemspec, we make some assumptions about your environment:

• git for SCM
• grep

Configuration

nucop can be configured by the YAML file .nucop.yml.

See the example config file .nucop.yml.example

Option	Description	Default
enforced_cops_file	List of Cops or Departments that will be enforced. Only violations of enforced cops will cause the diff_enforced command to fail.	.rubocop.enforced.yml
rubocop_todo_file	A generated file, containing the RuboCop TODO violations (i.e. RuboCop backlog)	.rubocop_todo.yml
rubocop_todo_config_file	RuboCop configuration that will generate the list of RuboCop TODO violations	.rubocop.backlog.yml
diffignore_file	A file of paths or files that removed. Must be passable to grep -f.	.nucop_diffignore

TODO

• Update README
  • Describe features
  • Document commands
• Undocumented option junit_report in rubocop command
• Introduce RubocopCommandBuilder
• Add tests!

License

The gem is available as open source under the terms of the MIT License.