ActiveRecord TypeError: can't dup Symbol

[DEfusion]

Running a query via select_all on a custom mysql2 connection is throwing a TypeError: can't dup Symbol in ActiveRecord::Result line 33.

The mysql2 connection is being made via the following:

ActiveRecord::Base.mysql2_connection(
    :host => Settings.import_db[:hostname],
    :username => Settings.import_db[:username],
    :password => Settings.import_db[:password],
    :database => Settings.import_db[:database],
    :port => Settings.import_db[:port],
    :reconnect => true
)

Issue present in 3.2.13

[schneems]

Are you specifying your host, username, password, database, or port as a symbol? Without exposing sensitive information can you run

$ bundle open activerecord

Then modify line 33 to be

columns = @columns.map { |c| 
  puts c.inspect
  c.dup.freeze 
}

Then try to initialize a DB connection and paste the output here? Don't forget to change that line back when done.

[senny]

@DEfusion is this still a problem? Did the advice from @schneems help?

[muffinista]

I work with @DEfusion, and this is still a problem for us. We're communicating with a remote, non-Rails database via a custom mysql connection with symbolize_keys set like so:

    Mysql2::Client.default_query_options.merge!(
        :symbolize_keys => true
    )

I put a line similar to the one @schneems suggested. All of the output from Rails is arrays of strings like this:

["id", "account_id", "test", "created_at", "updated_at", "state"]

While arrays from our remote db are of symbols like so:

[:id, :domain, :enabled]

I can fix this problem by changing the map to look like this:

      columns = @columns.map { |c| c.is_a?(Symbol) ? c : c.dup.freeze }

And I can submit a PR for that, but it's not clear to me that it's actually the best solution.

[rafaelfranca]

@muffinista could you provide the pull request so we can discuss the solution?

[rafaelfranca]

Closed as stale. If you think it is still an issue let us know