[Fix #365] Mark Rails/SquishedSQLHeredocs unsafe for autocorrection

[tejasbubane]

Closes #365

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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.
• 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.
• If this is a new cop, consider making a corresponding update to the Rails Style Guide.

[koic]

I think this cop should be aware of false positives in SQL comment line. So I think it can be resolved safely to the issue.

[andyw8]

I'm not sure where would be appropriate, but I think would be helpful to mention the reason somewhere, since it's safe as long as comments aren't used.

[greenfork]

It is also not safe when using with postgres functions, in my example in returns error when squishing $$ which is used for function beginning or ending

[Drenmi]

@tejasbubane I added a suggestion documenting the rationale for this above. 🙂

[koic]

Is this really unsafe? I think this cop can make safety by noticing SQL comment and other suggestion. I think these false positives are essential issue in the current implementation.

[Drenmi]

Is this really unsafe? I think this cop can make safety by noticing SQL comment and other suggestion.

Hm. We'd need to embed knowledge about several possible SQL dialects into RuboCop and also keep that up to date? 😅

[koic]

Ah, I see. Let's separate the two issues.

First, I think that it is difficult to collect SQL dialects and embed them. So, I agree with @Drenmi's opinion :-)

Second, I think SQL comment (and other SQL dialects) reported in the issue can be treated (fixes the false positive). So, I think this cop can make aware of SQL comment and provide an allow list for unknown SQL dialects. This feature will be an extension different from this PR.

[tejasbubane]

@koic @Drenmi I have added the suggested comment.

[koic]

Thanks!