Problem with yamllint configuration file

Processing a repository which does not have specified rules in .yamllint configuration file will result in:

Called from /root/.rbenv/versions/2.3.6/lib/ruby/gems/2.3.0/gems/activesupport-4.2.10/lib/active_support/dependencies.rb:240:in `load_dependency'
2018-04-21T12:59:14.996Z 3748 TID-grgzknuxk CommitMonitorHandlers::CommitRange::RubocopChecker JID-5e5788c93fcadd6dc8e7ba96 INFO: fail: 3.448 sec
2018-04-21T12:59:14.997Z 3748 TID-grgzknuxk WARN: {"class":"CommitMonitorHandlers::CommitRange::RubocopChecker","args":[2,["265235e76fa59718486c042a0650443d18400e6e"]],"retry":true,"queue":"miq_bot_glacial","jid":"5e5788c93fcadd6dc8e7ba96","created_at":1524315367.5318902,"enqueued_at":1524315551.5467553,"error_message":"undefined method `captures' for nil:NilClass\nDid you mean?  capture","error_class":"NoMethodError","failed_at":1524315372.3904035,"retry_count":1,"retried_at":1524315554.9960437}
2018-04-21T12:59:14.997Z 3748 TID-grgzknuxk WARN: NoMethodError: undefined method `captures' for nil:NilClass
Did you mean?  capture
2018-04-21T12:59:14.997Z 3748 TID-grgzknuxk WARN: /root/miq_bot/lib/linter/yaml.rb:44:in `line_to_hash'
/root/miq_bot/lib/linter/yaml.rb:7:in `block in parse_output'
/root/miq_bot/lib/linter/yaml.rb:7:in `collect'
/root/miq_bot/lib/linter/yaml.rb:7:in `parse_output'
/root/miq_bot/lib/linter/base.rb:31:in `run'
/root/miq_bot/app/workers/concerns/code_analysis_mixin.rb:26:in `run_all_linters'
/root/miq_bot/app/workers/concerns/code_analysis_mixin.rb:12:in `merged_linter_results'
/root/miq_bot/app/workers/commit_monitor_handlers/commit_range/rubocop_checker.rb:25:in `process_branch'
/root/miq_bot/app/workers/commit_monitor_handlers/commit_range/rubocop_checker.rb:19:in `perform'
/root/.rbenv/versions/2.3.6/lib/ruby/gems/2.3.0/gems/sidekiq-4.1.4/lib/sidekiq/processor.rb:152:in `execute_job'
/root/.rbenv/versions/2.3.6/lib/ruby/gems/2.3.0/gems/sidekiq-4.1.4/lib/sidekiq/processor.rb:134:in `block (2 levels) in process'
/root/.rbenv/versions/2.3.6/lib/ruby/gems/2.3.0/gems/sidekiq-4.1.4/lib/sidekiq/middleware/chain.rb:128:in `block in invoke'
/root/.rbenv/versions/2.3.6/lib/ruby/gems/2.3.0/gems/sidetiq-0.7.2/lib/sidetiq/middleware/history.rb:8:in `call'
/root/.rbenv/versions/2.3.6/lib/ruby/gems/2.3.0/gems/sidekiq-4.1.4/lib/sidekiq/middleware/chain.rb:130:in `block in invoke'
/root/.rbenv/versions/2.3.6/lib/ruby/gems/2.3.0/gems/sidekiq-4.1.4/lib/sidekiq/middleware/server/active_record.rb:6:in `call'
/root/.rbenv/versions/2.3.6/lib/ruby/gems/2.3.0/gems/sidekiq-4.1.4/lib/sidekiq/middleware/chain.rb:130:in `block in invoke'
/root/.rbenv/versions/2.3.6/lib/ruby/gems/2.3.0/gems/sidekiq-4.1.4/lib/sidekiq/middleware/server/retry_jobs.rb:74:in `call'
/root/.rbenv/versions/2.3.6/lib/ruby/gems/2.3.0/gems/sidekiq-4.1.4/lib/sidekiq/middleware/chain.rb:130:in `block in invoke'
/root/.rbenv/versions/2.3.6/lib/ruby/gems/2.3.0/gems/sidekiq-4.1.4/lib/sidekiq/middleware/server/logging.rb:11:in `block in call'
/root/.rbenv/versions/2.3.6/lib/ruby/gems/2.3.0/gems/sidekiq-4.1.4/lib/sidekiq/logging.rb:32:in `with_context'
/root/.rbenv/versions/2.3.6/lib/ruby/gems/2.3.0/gems/sidekiq-4.1.4/lib/sidekiq/middleware/server/logging.rb:7:in `call'
/root/.rbenv/versions/2.3.6/lib/ruby/gems/2.3.0/gems/sidekiq-4.1.4/lib/sidekiq/middleware/chain.rb:130:in `block in invoke'
/root/.rbenv/versions/2.3.6/lib/ruby/gems/2.3.0/gems/sidekiq-4.1.4/lib/sidekiq/middleware/chain.rb:133:in `invoke'
/root/.rbenv/versions/2.3.6/lib/ruby/gems/2.3.0/gems/sidekiq-4.1.4/lib/sidekiq/processor.rb:129:in `block in process'
/root/.rbenv/versions/2.3.6/lib/ruby/gems/2.3.0/gems/sidekiq-4.1.4/lib/sidekiq/processor.rb:168:in `stats'
/root/.rbenv/versions/2.3.6/lib/ruby/gems/2.3.0/gems/sidekiq-4.1.4/lib/sidekiq/processor.rb:128:in `process'
/root/.rbenv/versions/2.3.6/lib/ruby/gems/2.3.0/gems/sidekiq-4.1.4/lib/sidekiq/processor.rb:80:in `process_one'
/root/.rbenv/versions/2.3.6/lib/ruby/gems/2.3.0/gems/sidekiq-4.1.4/lib/sidekiq/processor.rb:68:in `run'
/root/.rbenv/versions/2.3.6/lib/ruby/gems/2.3.0/gems/sidekiq-4.1.4/lib/sidekiq/util.rb:17:in `watchdog'
/root/.rbenv/versions/2.3.6/lib/ruby/gems/2.3.0/gems/sidekiq-4.1.4/lib/sidekiq/util.rb:25:in `block in safe_thread'

NOTE: yamllint has its default rules see here.

The problem starts at line number 7 in lib/linter/yaml.rb:

parsed = lines.collect { |line| line_to_hash(line) }

[1] pry(#<Linter::Yaml>)> lines
=> ["{\"files\":[{\"path\":\"\\\\*\\\\*\",\"offenses\":[{\"severity\":\"fatal\",\"message\":\"Linter::Yaml STDERR:\\n```\\ninvalid config: not a dict\\n\\n```\",\"cop_name\":\"Linter/Yaml\"}]}],\"summary\":{\"offense_count\":1,\"target_file_count\":3,\"inspected_file_count\":3}}"]

in line_to_hash(line) at:

severity, message = severity_message.match(/\[(.*)\] (.*)/).captures

where .captures is called on nil:NilClass:

[3] pry(#<Linter::Yaml>)> severity_message
=> "[{\"severity\":\"fatal\",\"message\":\"Linter::Yaml STDERR:\\n```\\ninvalid config: not a dict\\n\\n```\",\"cop_name\":\"Linter/Yaml\"}]}],\"summary\":{\"offense_count\":1,\"target_file_count\":3,\"inspected_file_count\":3}}"

[4] pry(#<Linter::Yaml>)> severity_message.match(/\[(.*)\] (.*)/)
=> nil

Related issue: https://github.com/ManageIQ/miq_bot/issues/392