Fix undefined method 'join' for an instance of String on hover

[cpgo]

Working on a project that has lots of indexes created via raw sql, for example

execute "CREATE UNIQUE INDEX users_unique_complex ON users (COALESCE(country_id, 0), ltrim(first_name));"

I saw this exception on the lsp logs

/home/user/.asdf/installs/ruby/3.4.2/lib/ruby/gems/3.4.0/gems/ruby-lsp-rails-0.4.8/lib/ruby_lsp/ruby_lsp_rails/hover.rb:100:in 'block in RubyLsp::Rails::Hover#generate_column_content': undefined method 'join' for an instance of String (NoMethodError)

              "- **#{index[:name]}** (#{index[:columns].join(",")})#{uniqueness}"
                                                       ^^^^^

This pr attempts to handle that exception but I'm not familiar with the whole project structure so maybe the issue should be fixed somewhere upstream?

[vinistock]

Thank you for the PR! Just left a comment trying to understand all of the scenarios involved here

[vinistock]

Just trying to understand the different scenarios here. Array is the case when we have multiple columns associated to the index.

When is it a string? And when would it not be either (when do we reach the else block)?

In the case of the else block, we're essentially showing the index's name twice on the hover, which may not be super useful. Is there any other information for that scenario that we could show?

[cpgo]

I guess the else case is not really necessary, I just added because I'm not super familiar with the possible values here.

When is it a string?

I noticed on one of my applications when indexes contained "complex" sql processing like

execute "CREATE UNIQUE INDEX users_unique_complex ON users (COALESCE(country_id, 0), ltrim(first_name));"

In those cases .join was called on the whole index expression CREATE UNIQUE INDEX... instead of the array of columns