Add ViewPrimaryKeyChecker to enforce explicit primary_key on view-backed models

[Copilot]

ActiveRecord cannot derive a primary_key from schema introspection when a model points to a view. This checker enforces that such models explicitly declare self.primary_key = and that the declared column(s) actually exist in the view.

Changes

• New checker ViewPrimaryKeyChecker (model_checkers/) — runs only when connection.view_exists?(model.table_name) (AR 5.0+); reports two distinct failure modes:
  • :view_missing_primary_key — primary_key is nil/blank
  • :view_primary_key_column_missing — primary_key set but column(s) absent from the view
• Composite primary key support (Rails 7.1+) — all columns in a composite primary key array are validated against the view's columns
• New writers ViewMissingPrimaryKey and ViewPrimaryKeyColumnMissing with human-readable messages
• Registered checker and writers in database_consistency.rb
• Specs covering all branches: non-view table, abstract class, missing pk, bad single pk, valid single pk, valid composite pk, composite pk with missing column
• README / CHANGELOG updated

Example output

ViewPrimaryKeyChecker fail ReportView self model pointing to a view should have primary_key set
ViewPrimaryKeyChecker fail ReportView self model pointing to a view has a non-existent primary_key column set

Fix by adding to the model:

class ReportView < ApplicationRecord
  self.primary_key = :id
  # or for composite primary keys (Rails 7.1+):
  self.primary_key = [:shop_id, :id]
end

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Enforce setting primary_key for models that are pointing to views</issue_title>
<issue_description>It seems that ActiveRecord cannot derive a proper primary_key column name from its schema if the model is pointing to a view instead of a table.

We should implement a checker that ensures that every model that is pointing to a view has self.primary_key = explicitly set and that column exists in the view.

precondition:

• model points to a view

Fail if we:

• no column
• primary_key is not set
  </issue_description>

<agent_instructions>Implement this checker, cover it with specs and integeration tests, also update changelog, readme</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes Enforce setting primary_key for models that are pointing to views #281

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[djezzzl]

@copilot fix CI

[Copilot]

@copilot fix CI

Fixed in ff1068f. The failure was in the tests (2.6, gemfiles/ar_4_2.gemfile) job — view_exists? was introduced in ActiveRecord 5.0 and isn't available in AR 4.2, causing a NoMethodError that was rescued and made all view-context tests return nil. Added ActiveRecord::VERSION::MAJOR >= 5 guard to both the checker's preconditions and the spec's before block (consistent with how ThreeStateBooleanChecker handles it).

[djezzzl]

@copilot add support for composite primary keys (Rails 7.1+) and cover it with specs.

[Copilot]

@copilot add support for composite primary keys (Rails 7.1+) and cover it with specs.

Done in dcda624. Changed primary_key_column_exists? to use Array(model.primary_key).all? { |key| model.column_names.include?(key.to_s) } — Array() wraps a String into a single-element array for the single-PK case, and passes an Array through as-is for the composite-PK case. Added two new spec contexts (composite pk all columns exist → ok; one column missing → fail) both guarded with the standard compound_primary_keys_supported? skip.