Fix clobbering inherit_from additions when not using Namespaces in the configs

[NickLaMuro]

Overview

The current implementation of load_file will load the hash from a config, then apply the base_configs to that hash, before converting it to a proper Config object, which means we are comparing a vanilla Hash with a Config, so one will have the converted namespace Cop names, and the other will not. This can clobber inherited configuration since merging will happen in resolve_inheritance, but will just keep the keys from both and then when add_missing_namespaces is called, one will be dropped.

Since Config inherits from Hash, there shouldn't be a problem with doing the resolve_* methods after the config = Config.new line since all the normal Hash methods are available (.delete specifically).

Example (before this change)

Given the following files:

.rubocop.yml

inherit_from: ["base.yml"]

LineLength:
  Exclude: ["Gemfile"]

base.yml

LineLength:
  Max: 120

• .rubocop.yml is loaded through the load_file method

• it, in turn, loads base.yml when called in base_configs from resovle_inheritance

• When add_missing_namespaces is called on base.yml, it converts {"LineLength" => {"Max" => 120}} to have "Metrics/LineLength", and deletes old "LineLength" key

• The unconverted hash of '.rubocop.ymlis then merged with the convertedbase.yml`, and so the following hash exists:

  {
    "LineLength"         => {"Exclude" => ["Gemfile"]},
    "Metrics/LineLength" => {"Max"     => 120}
  }

• When add_missing_namespaces is called on the now merged .rubocop.yml config, it will delete the changes from "Metrics/LineLength" => {"Max" => 120} when converting "LineLength" to have a namespace, and the default LineLength max value will be used instead.

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[bdunne]

👍

[NickLaMuro]

<3 that there was a test to catch me spelling my username wrong in the CHANGELOG.md :D

[bbatsov]

Nice catch! Thanks for fixing this!

[NickLaMuro]

No problem, thanks for merging!