4.24.0: enum-backed integer columns annotate raw default(0) instead of default("label")

[laiskajoonas]

Summary

Since 4.24.0, annotations for integer columns backing a Rails enum render the raw
integer default instead of the enum label. Regenerating annotations on an unchanged
schema produces a diff on every such column:

-#  signing_provider_service :integer          default("idnow"), not null
+#  signing_provider_service :integer          default(0), not null

-#  base_portfolio           :integer          default("classic"), not null
+#  base_portfolio           :integer          default(0), not null

-#  role                     :integer          default("user"), not null
+#  role                     :integer          default(0), not null

4.23.0 produced the label form. In our app this touched ~45 files (models, serializers
and factories) purely from the gem bump, which fails the CI job that runs
rails db:migrate:reset and asserts a clean working tree.

Environment

• annotaterb 4.24.0 (4.23.0 is fine)
• Rails 8.1, Ruby 4.0
• PostgreSQL 17

Cause

I believe this is unintended fallout from #358 ("Respect DB column defaults over
attribute :foo, default: X overrides"), which rewrote ModelWrapper#column_defaults:

@column_defaults ||= @klass.column_defaults.each_with_object({}) do |(name, value), result|
  column = @klass.columns_hash[name]
  schema_value = schema_default_for(column)
  result[name] = (value == schema_value) ? value : schema_value
end

Model#column_defaults casts the DB default through the attribute type, so for an
enum column it yields the label ("idnow"). schema_default_for casts through the
column type, yielding 0. They differ, so the branch treats it as an
attribute-level override and substitutes the raw schema value — but for enums the
difference is inherent to how ActiveRecord::Enum decorates the attribute type, not
an attribute ... default: override.

Declaring an enum is enough to trigger it:

class AccountRequest < ApplicationRecord
  enum :signing_provider_service, {idnow: 0, fidentity: 1}, prefix: true
end
# 4.23.0: default("idnow")
# 4.24.0: default(0)

Expected

Enum-backed columns keep rendering their symbolic default, since that is the
meaningful value for a reader — while attribute :foo, default: X overrides continue
to show the DB schema default as #358 intended.

A possible discriminator: skip the substitution when the attribute type is an
ActiveRecord::Enum::EnumType (or, more generally, when the attribute type is a
decorator around the column's cast type rather than an independent default), instead
of inferring an override from value inequality alone.

I'm happy to put up a PR if you agree with that direction.

[kamipo]

We were also affected by this change (26 files in our case), but I actually prefer showing the raw database values in the annotations rather than values derived from the model’s type casting. At least to me, that feels like the expected behavior.

Do people generally expect annotations to reflect the model’s type-casted values instead (including enum type casting)?

[fschwahn]

Personally, I prefer to see the enum values. Maybe it could be a configuration option?

[dmke]

@kamipo:

Do people generally expect annotations to reflect the model’s type-casted values instead (including enum type casting)?

This has been established behaviour for years (I think), so at least I am now being accustomed to this presentation. But I can see the reasoning as to why this is surprising.

@fschwahn:

Personally, I prefer to see the enum values. Maybe it could be a configuration option?

Seconded.

[jbaxendale-ut]

@kamipo:

Do people generally expect annotations to reflect the model’s type-casted values instead (including enum type casting)?

This has been established behaviour for years (I think), so at least I am now being accustomed to this presentation. But I can see the reasoning as to why this is surprising.

@fschwahn:

Personally, I prefer to see the enum values. Maybe it could be a configuration option?

Seconded.

Considering the point here is convenience to development, IMO it is far more valuable to see "human_description" as opposed to "0"

Perhaps it could be a configuration option if not, but I held off upgrading due to this at the moment.