[Fix rubocop#3242] Ignore cache files disappearing during cleanup eve…

…n more (rubocop#3975)

We already ignore `Errno::ENOENT` during the removal, but `File.mtime`
might raise too.

CHANGELOG.md

@@ -22,6 +22,7 @@
 * [#2643](https://github.com/bbatsov/rubocop/issues/2643): Allow uppercase and dashes in `MagicComment`. ([@mikegee][])
 * [#3959](https://github.com/bbatsov/rubocop/issues/3959): Don't wrap "percent arrays" with extra brackets when autocorrecting `Style/MutableConstant`. ([@mikegee][])
 * [#3978](https://github.com/bbatsov/rubocop/pull/3978): Fix false positive in `Performance/RegexpMatch` with `English` module. ([@pocke][])
+* [#3242](https://github.com/bbatsov/rubocop/issues/3242): Ignore `Errno::ENOENT` during cache cleanup from `File.mtime` too. ([@mikegee][])
 
 ## 0.47.1 (2017-01-18)
 

lib/rubocop/result_cache.rb

@@ -44,20 +44,20 @@ def remove_oldest_files(files, dirs, cache_root, verbose)
  puts "Removing the #{remove_count} oldest files from #{cache_root}"
  end
  sorted = files.sort_by { |path| File.mtime(path) }
- remove_files(sorted, dirs, remove_count, verbose)
+ remove_files(sorted, dirs, remove_count)
+ rescue Errno::ENOENT
+ # This can happen if parallel RuboCop invocations try to remove the
+ # same files. No problem.
+ puts $ERROR_INFO if verbose
  end
 
- def remove_files(files, dirs, remove_count, verbose)
+ def remove_files(files, dirs, remove_count)
  # Batch file deletions, deleting over 130,000+ files will crash
  # File.delete.
  files[0, remove_count].each_slice(10_000).each do |files_slice|
  File.delete(*files_slice)
  end
  dirs.each { |dir| Dir.rmdir(dir) if Dir["#{dir}/*"].empty? }
- rescue Errno::ENOENT
- # This can happen if parallel RuboCop invocations try to remove the
- # same files. No problem.
- puts $ERROR_INFO if verbose
  end
  end