[Fix #7627] Fix a false negative for Migration/DepartmentName

Fixes #7627.

This PR fixes a false negative for `Migration/DepartmentName`
when there is space around `:`.

For example, `# rubocop : disable` is a valid syntax for
a disable comment.

CHANGELOG.md

@@ -18,6 +18,7 @@
 * [#7602](https://github.com/rubocop-hq/rubocop/pull/7602): Ensure proper handling of Ruby 2.7 syntax. ([@drenmi][])
 * [#7620](https://github.com/rubocop-hq/rubocop/issues/7620): Fix a false positive for `Migration/DepartmentName` when a disable comment contains a plain comment. ([@koic][])
 * [#7616](https://github.com/rubocop-hq/rubocop/issues/7616): Fix an incorrect autocorrect for `Style/MultilineWhenThen` for when statement with then is an array or a hash. ([@koic][])
+* [#7627](https://github.com/rubocop-hq/rubocop/issues/7627): Fix a false negative for `Migration/DepartmentName` when there is space around `:` (e.g. `# rubocop : disable`). ([@koic][])
 
 ### Changes
 

lib/rubocop/cop/migration/department_name.rb

@@ -10,14 +10,17 @@ class DepartmentName < Cop
 
         MSG = 'Department name is missing.'
 
+        DISABLE_COMMENT_FORMAT =
+          /\A(# *rubocop *: *((dis|en)able|todo) +)(.*)/.freeze
+
         # The token that makes up a disable comment.
         # The token used after `# rubocop: disable` are `A-z`, `/`, and `,`.
         # Also `A-z` includes `all`.
         DISABLING_COPS_CONTENT_TOKEN = %r{[A-z/,]+}.freeze
 
         def investigate(processed_source)
           processed_source.each_comment do |comment|
-            next if comment.text !~ /\A(# *rubocop:((dis|en)able|todo) +)(.*)/
+            next if comment.text !~ DISABLE_COMMENT_FORMAT
 
             offset = Regexp.last_match(1).length
             Regexp.last_match(4).scan(%r{[\w/]+|\W+}) do |name|

spec/rubocop/cop/migration/department_name_spec.rb

@@ -33,6 +33,26 @@
         # rubocop:enable Style/Alias, Layout/LineLength
       RUBY
     end
+
+    it 'registers offenses and corrects when there is space around `:`' do
+      expect do
+        expect_offense(<<~RUBY, 'file.rb')
+          # rubocop : todo Alias, LineLength
+                                  ^^^^^^^^^^ Department name is missing.
+                           ^^^^^ Department name is missing.
+          alias :ala :bala
+          # rubocop : enable Alias, LineLength
+                                    ^^^^^^^^^^ Department name is missing.
+                             ^^^^^ Department name is missing.
+        RUBY
+      end.to output(warning).to_stderr
+
+      expect_correction(<<~RUBY)
+        # rubocop : todo Style/Alias, Layout/LineLength
+        alias :ala :bala
+        # rubocop : enable Style/Alias, Layout/LineLength
+      RUBY
+    end
   end
 
   context 'when a disable comment has cop names with departments' do