"undefined method `null' for nil:NilClass" in column_presence_checker.rb:54

[asavageiv]

/Users/asavage/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/database_consistency-1.7.5/lib/database_consistency/checkers/validators_fraction_checkers/column_presence_checker.rb:54:in `analyse': undefined method `null' for nil:NilClass (NoMethodError)

        can_be_null = field.null
                           ^^^^^
        from /Users/asavage/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/database_consistency-1.7.5/lib/database_consistency/checkers/validators_fraction_checkers/column_presence_checker.rb:43:in `check'
        from /Users/asavage/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/database_consistency-1.7.5/lib/database_consistency/checkers/base_checker.rb:25:in `report'
        from /Users/asavage/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/database_consistency-1.7.5/lib/database_consistency/checkers/base_checker.rb:34:in `report_if_enabled?'
        from /Users/asavage/.rbenv/versions/3.1.3/lib/ruby/gems/3.1.0/gems/database_consistency-1.7.5/lib/database_consistency/processors/validators_fractions_processor.rb:23:in `block (3 levels) in check'

database_consistency_2023_04_09_08_42_23.txt

[asavageiv]

My first guess is it's a failure because the user_id column is missing on the payments table.

#<DatabaseConsistency::Checkers::ColumnPresenceChecker:0x000000010d9a0e58
 @association=
  #<ActiveRecord::Reflection::BelongsToReflection:0x000000010d551910
   @active_record=Payment(id: uuid, fulfillable_type: string, fulfillable_id: uuid, checkout_payment_id: string, checkout_payment_data: jsonb, metadata: jsonb, created_at: datetime, updated_at: datetime),
   @class_name="User",
   @constructable=true,
   @foreign_key="user_id",
   @klass=
    User(id: uuid),
   @name=:user,
   @options={},
   @plural_name="users",
   @scope=nil>,
 @attribute=:user,
 @checker_name="ColumnPresenceChecker",
 @column_or_attribute_name="user",
 @model=Payment(id: uuid, fulfillable_type: string, fulfillable_id: uuid, checkout_payment_id: string, checkout_payment_data: jsonb, metadata: jsonb, created_at: datetime, updated_at: datetime),
 @regular_column=nil,
 @table_or_model_name="Payment",
 @validators=[#<ActiveRecord::Validations::PresenceValidator:0x000000010d548860 @attributes=[:user], @options={:message=>:required}>]>

  create_table "payments", id: :uuid, default: -> { "public.gen_random_uuid()" }, force: :cascade do |t|
    t.string "fulfillable_type"
    t.uuid "fulfillable_id"
    t.string "checkout_payment_id"
    t.jsonb "checkout_payment_data", default: {}, null: false
    t.jsonb "metadata", default: {}, null: false
    t.datetime "created_at", precision: 6, null: false
    t.datetime "updated_at", precision: 6, null: false
    t.index ["fulfillable_type", "fulfillable_id"], name: "index_payments_on_fulfillable"
  end

create_table "users", id: :uuid, default: -> { "public.gen_random_uuid()" }, force: :cascade do |t|
...
end

[asavageiv]

Reproducible with this in column_presence_checker_spec:

  context 'when the column for the `belongs_to` foreign key is missing' do
    let(:attribute) { :user }
    let(:klass) { define_class { |klass| klass.belongs_to :user, foreign_key: 'user_id', **required } }

    before do
      define_database do
        create_table :entities
      end
    end

    specify do
      expect(checker.report(catch_errors: false)).to be_nil
    end
  end

[djezzzl]

Hi @asavageiv,

First, thank you for using the gem and reporting the issue! One more thank you for the contribution with the fixing PR!

As I can see, the root cause of the issue is an invalid association, is it?

Do you think we should just ignore it or report that the association is invalid? Or do you think it should be a separate check instead?

[asavageiv]

Whoops, I thought I responded to this a while back, but I guess I forgot to hit "send"!

I guess it depends on how it would impact configuration. Would we want to include/exclude that check separately? I would guess "yes". Checking for a presence validation is not the same thing as checking for an association column existing at all.

[djezzzl]

I agree with you. We could introduce checkers for finding "dead"/invalid code.

Could you please address issues on your PR so I can merge it? And, by the way, do you want to contribute with a separate checker for the issue we talked about?

[asavageiv]

Actually it already seems to be present in ForeignKeyTypeChecker. I got the following error: ForeignKeyTypeChecker fail Payment user association (user) of class (Payment) relies on field (user_id) of table (payments) but it is missing

[djezzzl]

Oh, you're right. I think it would be good to extract it to a separate checker. Would you agree?