Solution for errors that occur when upgrading to Rails 5.2 series

Introduction

As a Rails beginner, I have summarized the points I stumbled upon as a memorandum.

Learning materials

Rails engineer training course taught by full stack engineers

Problem ①

The following error occurred when updating the Rails version to 5.2 series with Gemfile and starting the container.

Exiting
web_1  | /app/config/initializers/new_framework_defaults.rb:21:in `<top (required)>': undefined method `halt_callback_chains_on_return_false=' for ActiveSupport:Module (NoMethodError)

Solutions

You can tell by reading the error, It can be read that the cause is the ** halt_callback_chains_on_return_false ** method of /app/config/initializers/new_framework_defaults.rb. After investigating, it seems that halt_callback_chains_on_return_false has been removed from Rails 5.2, so commenting it out can solve the problem.

new_framework_defaults.rb

# Do not halt callback chains when a callback returns false. Previous versions had true.
#ActiveSupport.halt_callback_chains_on_return_false = false <=Comment out

Problem ②

Test with Rspec from command

docker-compose exec web bundle exec rspec ./spec/models/

Then, the following error is output (error excerpt)

rails aborted!
ActiveRecord::MismatchedForeignKey: Column `board_id` on table `board_tag_relations` has a type of `int(11)`.
This does not match column `id` on `boards`, which has type `bigint(20)`.
To resolve this issue, change the type of the `board_id` column on `board_tag_relations` to be :integer. (For example `t.integer board_id`).

Solutions

Before 5.1 series, when migration is created, the id column is created with int by default, but from 5.1 series this is changed to big int. Since FK constraints cannot be set between columns with different types, it is necessary to unify the types.

• board_tag_relations.board_id is ** bigint type **
• boards.id is ** int type **

As a solution, modify board_tag_relations.board_id to int type and db: migrate: reset to solve the problem.

problem

Error occurred in redirect_to: back

redirect_to :back, flash: {
        user: user,
        error_messages: user.errors.full_messages
      }

Solutions

From Rails 5.1 series It has been replaced with redirect_to: back =>redirect_back (fallback_location: root_path), so if you fix it, the problem will be solved.

redirect_back(fallback_location: "http://localhost", 
      flash: {
        user: user,
        error_messages: user.errors.full_messages
      })

reference

• Notes about problems when updating the rails 5.1.6 app to rails 5.2.0
• Solution for the problem that FK constraints cannot be placed on tables created before Rails 5.1
• Redirect_to: back is clear from Rails 5.1 series