fix: Drep retirement should clear accounts, not expiration

[gonzalezzfelipe]

Summary by CodeRabbit

• New Features

  • Governance views now use retirement-by-epoch, showing more accurate DRep active/retired status.
  • Added support for additional Conway certificate variants (StakeRegDeleg, StakeVoteRegDeleg) across delegation and account processing.

• Bug Fixes

  • Corrected DRep expiration and retirement handling to prevent premature or unconditional updates.
  • Account active epoch now falls back to deregistration when registration timing is unavailable, improving timeline accuracy.

• Refactor

  • Internal DRep lifecycle tracking moved from a boolean flag to epoch-based retirement for clearer state transitions.

[coderabbitai]

Caution

Review failed

The pull request is closed.

Walkthrough

Refactors DRep lifecycle to use retiring_epoch and deposit, removes deprecated fields, updates serialization indices, and adjusts apply/undo logic and sweep conditions. Extends certificate handling across minibf builders and routes, and updates governance active/retired checks to rely on retiring_epoch and current epoch.

Changes

Cohort / File(s)	Summary
Cardano model: DRepState crates/cardano/src/model.rs	Replaces retired flag and deprecated __drep_id with retiring_epoch: Option and deposit: u64; reorders CBOR indices; updates constructor accordingly.
Roll: DRep registration/unregistration flow crates/cardano/src/roll/dreps.rs	Introduces epoch-aware unregistration via retiring_epoch; modifies DRepRegistration/DRepUnRegistration apply/undo to track prev_retiring_epoch; DRepStateVisitor propagates epoch and computes retiring_epoch as epoch+1.
Sweep: retire/expire logic crates/cardano/src/sweep/retires.rs	Adds should_retire_drep; adjusts should_expire_drep to ignore retired; visit_drep now conditionally emits expiration and delegator-drop deltas based on new checks.
Minibf mapping: delegations and stake certs crates/minibf/src/mapping.rs	Handles ConwayCert StakeRegDeleg and StakeVoteRegDeleg as delegations; expands StakeCertModelBuilder to set registration flags for Reg/RegDeleg/VoteRegDeleg and UnReg.
Minibf routes: accounts crates/minibf/src/routes/accounts.rs	active_epoch derives from registered_at or deregistered_at; broadens registration handling to Reg, UnReg, StakeRegDeleg, StakeVoteRegDeleg.
Minibf routes: governance crates/minibf/src/routes/governance.rs	Adds is_drep_retired using retiring_epoch vs current_epoch; updates is_drep_active and Drep model retired field accordingly; preserves special-case handling.

Sequence Diagram(s)

sequenceDiagram
  autonumber
  actor Chain
  participant Visitor as DRepStateVisitor
  participant Roll as DRepRegistration/UnRegistration
  participant State as DRepState

  Note over Chain,Visitor: Process governance certs within a block/epoch
  Chain->>Visitor: visit_root(epoch)
  Note right of Visitor: Store current epoch

  alt Register DRep
    Chain->>Visitor: visit_cert(RegDRep)
    Visitor->>Roll: DRepRegistration::new(drep)
    Roll->>State: apply() sets retiring_epoch=None
  else Unregister DRep
    Chain->>Visitor: visit_cert(UnRegDRep)
    Visitor->>Roll: DRepUnRegistration::new(drep, epoch+1)
    Roll->>State: apply() sets retiring_epoch=Some(epoch+1)
  end

  Note over Roll,State: undo restores prev_retiring_epoch

Loading

sequenceDiagram
  autonumber
  participant Sweep as Sweep::retires
  participant Ctx as SweepCtx
  participant State as DRepState
  participant Delta as Deltas

  Sweep->>Ctx: current starting epoch
  Sweep->>State: read retiring_epoch, last_active_slot
  alt should_retire_drep
    Sweep->>Delta: push DRepDelegatorDrop for each delegator
  end
  alt should_expire_drep
    Sweep->>Delta: push DRepExpiration
  end

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Estimated code review effort

🎯 4 (Complex) | ⏱️ ~45–60 minutes

Possibly related PRs

• fix(cardano): clear delegators on retiring drep #707: Overlapping changes to DRep retirement handling and DRepState fields across model, roll, and sweep modules.
• chore: Handle drep and pool retirements #704: Introduces epoch-aware retirement; closely aligned with retiring_epoch flow added here.
• refactor(cardano): deprecate redundant drep id state value #709: Previous adjustments to DRepState drep_id handling; this PR removes __drep_id and reorders fields.

Suggested reviewers

• scarmuega

Poem

I hop through epochs, tick by tick,
Retiring Dreps with a gentle flick.
No more flags, just time’s soft nudge—
A slot, an epoch, ledgers judge.
Delegators drop, expiries chime—
Carrots count deposits, right on time. 🥕⏳

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch fix/drep-retirement

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📜 Recent review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 1c92b7d and 15f211f.

📒 Files selected for processing (6)

• crates/cardano/src/model.rs (1 hunks)
• crates/cardano/src/roll/dreps.rs (7 hunks)
• crates/cardano/src/sweep/retires.rs (2 hunks)
• crates/minibf/src/mapping.rs (2 hunks)
• crates/minibf/src/routes/accounts.rs (2 hunks)
• crates/minibf/src/routes/governance.rs (2 hunks)

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