Issuable

The shared abstraction over Issue, MergeRequest, and (via the new framework) WorkItem.

Source

• app/models/concerns/issuable.rb — core mixin.
• app/models/concerns/has_internal_id.rb — IID generation.
• app/services/issuable_base_service.rb — service-layer base class.
• app/finders/issuable_finder.rb — common finder logic.

Shared behavior

All issuables have:

• A title and description (Markdown, rendered by Banzai).
• Author, assignee(s), reviewers (MR-only).
• Labels, milestone (and iteration on EE).
• A discussion thread of Notes.
• An award emoji ("reactions") collection.
• Subscribers and notification settings.
• Internal IDs (iid) scoped to the parent project/group.
• A state (open, closed, merged for MRs).
• Confidentiality flag.
• Lock/unlock for discussion control.
• A "moved to" pointer for issue moves.

Internal IDs

Issuables have a global PK (id) and a per-parent IID (iid). The IID is what users see (#42). Generation uses the internal_ids table with row-level locking to ensure uniqueness without sequence collisions.

Quick actions

/assign @alice, /label ~bug, /close etc. are parsed by Banzai::QuickActionService and app/services/quick_actions/. They modify the issuable in the same transaction as the comment that contained them.

Search and filtering

IssuableFinder is the largest finder; it accepts ~30 filter parameters and produces an ActiveRecord::Relation. Used by:

• The web UI list pages.
• REST API list endpoints.
• GraphQL resolvers.
• Boards.

Workflows

Each issuable has its own state machine:

• Issue: open → closed.
• MR: open → closed; open → merged; reopened.

The state column drives lookups; transitions emit notifications and todos.

Related

• Issues and work items.
• Source code management — MRs.
• Banzai — descriptions and comments.