Add new Rails/SquishedSQLHeredocs cop

[mobilutz]

This cops check <<-SQL SQL-heredocs if they use .squish or not.

Base is this styleguide: Squished Heredocs

---

Before submitting the PR make sure the following are checked:

• Wrote good commit messages.
• Commit message starts with [Fix #issue-number] (if the related issue exists).
• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• Added tests.
• Added an entry to the Changelog if the new code introduces user-observable changes. See changelog entry format.
• If this is a new cop, consider making a corresponding update to the Rails Style Guide.
• The PR relates to only one subject with a clear title
  and description in grammatically correct, complete sentences.
• Run bundle exec rake default. It executes all tests and RuboCop for itself, and generates the documentation.

[eugeneius]

Thanks for working on this!

[eugeneius]

Sorry @mobilutz, I just realised that my earlier suggestion about single-line heredocs was wrong. Even when a heredoc is only a single line, it still always has a trailing newline character:

$ ruby -e "puts <<~SQL.inspect
SELECT * FROM posts
SQL"
"SELECT * FROM posts\n"

Since the point of the style guide entry is to avoid logging newline characters, I think we should actually enforce squish in all cases, as you had originally. 😖

[mobilutz]

Since the point of the style guide entry is to avoid logging newline characters, I think we should actually enforce squish in all cases, as you had originally. 😖

Thanks for testing it out again, I totally did not do that.
I will revert the single line check so that squish will be used on all heredocs.

[mobilutz]

@eugeneius Any chance you could review this again?
Thanks

[eugeneius]

Here's a few changes that make the inline case work correctly:

diff --git a/spec/rubocop/cop/rails/squished_sql_heredocs_spec.rb b/spec/rubocop/cop/rails/squished_sql_heredocs_spec.rb
index 340d317a3..a3b132c00 100644
--- a/spec/rubocop/cop/rails/squished_sql_heredocs_spec.rb
+++ b/spec/rubocop/cop/rails/squished_sql_heredocs_spec.rb
@@ -58,8 +58,16 @@ RSpec.describe RuboCop::Cop::Rails::SquishedSQLHeredocs, :config do

   context 'with heredocs as method parameters' do
     it 'does not register an offense' do
-      expect_no_offenses(<<-RUBY)
+      expect_offense(<<~RUBY)
         execute(<<~SQL, "Post Load")
+                ^^^^^^ Use `<<~SQL.squish` instead of `<<~SQL`.
+          SELECT * FROM posts
+            WHERE post_id = 1
+        SQL
+      RUBY
+
+      expect_correction(<<~RUBY)
+        execute(<<~SQL.squish, "Post Load")
           SELECT * FROM posts
             WHERE post_id = 1
         SQL

[mobilutz]

@eugeneius Thank you very much for the great input! Now even method-parameter Heredocs are working!!!

I rebased origin/master and added hopefully all documentation etc.
Is there anything else I can do to make this PR mergeable?

[eugeneius]

This is looking good to me! I added a few more suggestions.

[koic]

@mobilutz Can you update this PR?

[mobilutz]

@mobilutz Can you update this PR?

Thanks for the reminder.

@eugeneius Thanks for your great reviews!

[eugeneius]

Looks great, thanks for sticking with this @mobilutz!

[koic]

Thank you!

[mobilutz]

@koic It seems, that the changelog entry is not in the correct place 😦
v2.7.1...master#diff-4ac32a78649ca5bdd8e0ba38b7006a1eR43

PS: I create a new PR to fix this: #333

[koic]

@mobilutz Good catch! I updated the changelog. Thank you!
ef26793