CIP-82 (DAML): Add support for DevelopmentFundCoupon

[jose-velasco-ieu]

Summary

This PR introduces the DAML-side support for the Development Fund mechanism defined in CIP-82.
The core design and ledger model were originally developed in the draft PR #3086, and this PR builds on top of that work with additional fixes and updates required to make the implementation fully consistent with the current codebase.

1. New template: UnclaimedDevelopmentFundCoupon

A new ledger contract, UnclaimedDevelopmentFundCoupon, represents the portion of newly minted Amulet allocated to the Development Fund.

• Each coupon is created and owned by the DSO.
• It records the total amount of Amulet allocated to the Development Fund for a given issuance round.
• Coupons do not expire:
  • ACS size control is achieved through explicit merging rather than expiry.
  • These contracts are purely accounting instruments and do not require availability incentives.

---

2. New template: DevelopmentFundCoupon

A new ledger contract, DevelopmentFundCoupon, represents an allocation of Development Fund minting rights to a specific beneficiary.

• Created when the Development Fund Manager allocates part of the unclaimed fund entitlement.
• Records the total amount of Amulet the beneficiary is entitled to mint directly to themselves.
• Lifecycle operations:
  • Withdrawal by the Development Fund Manager, restoring the amount back into an UnclaimedDevelopmentFundCoupon.
  • Expiry by the DSO, similarly consuming the allocated coupon and restoring the amount into an unclaimed coupon.

---

3. Configuration extensions (AmuletConfig and IssuanceConfig)

The Amulet configuration is extended to support the Development Fund:

• IssuanceConfig

  • Adds optDevelopmentFundPercentage, defining the fraction of each mint emission allocated to the Development Fund.
  • Validation ensures 0.0 ≤ percentage ≤ 1.0, preventing invalid or over-allocating configurations.

• AmuletConfig

  • Adds optDevelopmentFundManager, identifying the Development Fund Manager, i.e. the party authorized to allocate Development Fund entitlements to final recipients.

---

4. AmuletRules enhancements

The AmuletRules contract is extended to support Development Fund issuance and management:

AmuletRules_MiningRound_StartIssuing

• Deducts the Development Fund’s share before distributing rewards to Validators, Super Validators, and Apps.
• The deduction is proportional to optDevelopmentFundPercentage and reflected consistently in all issuance parameters.
• When the allocation is non-zero, a new UnclaimedDevelopmentFundCoupon is created for the round.

AmuletRules_MergeUnclaimedDevelopmentFundCoupons

• Introduces a batch merge operation, exercisable by the DSO.
• Requires at least two active unclaimed coupons.
• Aggregates their amounts into a single new UnclaimedDevelopmentFundCoupon.

AmuletRules_AllocateDevelopmentFundCoupon

• Allows the Development Fund Manager to allocate Development Fund entitlement to a beneficiary.
• Key properties:
  • Controller: Development Fund Manager (optDevelopmentFundManager).
  • Consumes one or more UnclaimedDevelopmentFundCoupon contracts.
  • Deducts the specified allocation amount.
  • Creates a new DevelopmentFundCoupon with beneficiary, amount, and expiry.
  • Any remaining unclaimed balance is returned as a new UnclaimedDevelopmentFundCoupon, ensuring that no entitlement is lost.

AmuletRules_Transfer

• Transfer logic is extended to accept DevelopmentFundCoupon as a valid input.
• Consumption is permitted only if the sender matches the coupon beneficiary.
• TransferResult is extended with:
  • totalDevelopmentFundAmount, tracking the total Development Fund amount consumed in the transaction for auditability and reporting.

---

5. Governance integration (DsoRules)

• Adds DsoRules_MergeUnclaimedDevelopmentFundCoupons, allowing the DSO to invoke the merge operation at the governance layer.
• This choice delegates to the same underlying logic as AmuletRules_MergeUnclaimedDevelopmentFundCoupons.

---

6. Additional changes since the original draft

Compared to the original draft PR (#3086), this PR also includes:

• Bumping DAML package versions to reflect the new templates and rules.
• Fixes to Scala and TypeScript compilation, required to align the application code with the updated DAML configuration and contract model.
• Making IssuingRoundParameters compliant with SCU, aligning issuance parameters with the updated supply and issuance model.

Pull Request Checklist

Cluster Testing

• If a cluster test is required, comment /cluster_test on this PR to request it, and ping someone with access to the DA-internal system to approve it.
• If a hard-migration test is required (from the latest release), comment /hdm_test on this PR to request it, and ping someone with access to the DA-internal system to approve it.

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Merge Guidelines

• Make the git commit message look sensible when squash-merging on GitHub (most likely: just copy your PR description).

[mergify]

⚠️ The sha of the head commit of this PR conflicts with #3086. Mergify cannot evaluate rules on this PR. ⚠️

[meiersi-da]

Very nice work! Thank you @jose-velasco-ieu 🙇

Approving with suggestions: https://neilmitchell.blogspot.com/2019/04/code-review-approve-with-suggestions.html

[meiersi-da]

Something is fishy about this file. It's is larger than splice-wallet, which sits farther down in the dependency tree. The size here is also exactly the same 1.18 MB as splice-dso-governance. Can you unzip and compare the contents?

[jose-velasco-ieu]

They are different.
inspect-dar-splice-dso-governance-0.1.21.json
inspect-dar-splice-amulet-0.1.15.json

Notice that in main we have the same situation:
https://github.com/hyperledger-labs/splice/tree/main/daml/dars

[meiersi-da]

check amount of left-over funds

[jose-velasco-ieu]

done

[meiersi-da]

Suggested change

	let amuletsToIssueToDevelopmentFund = fromOptional 0.0 params.optAmuletsToIssueToDevelopmentFund
	unclaimedDevelopmentFundCouponCid <-
	if amuletsToIssueToDevelopmentFund > 0.0
	then
	Some <$> create UnclaimedDevelopmentFundCoupon with
	dso
	amount = amuletsToIssueToDevelopmentFund
	else pure None
	unclaimedDevelopmentFundCouponCid <- forA params.optAmuletsToIssueToDevelopmentFund $ \amount ->
	create UnclaimedDevelopmentFundCoupon with
	dso
	amount
	```

[jose-velasco-ieu]

How about if the amount is zero? We would be creating a 0 amount coupon.

[meiersi-da]

o.O, I see. I've overlooked that.

I'd still recommend an explicit case distinction then for clarity:

  case params.optAmuletsToIssueToDevelopmentFund of
   Some amount | amount > 0.0 -> 
     create UnclaimedDevelopmentFundCoupon with dso; amount 
   _ -> pure None

[jose-velasco-ieu]

done

[meiersi-da]

Suggested change

	-- Batch merge of unclaimed development fund coupons
	nonconsuming choice AmuletRules_MergeUnclaimedDevelopmentFundCoupons : AmuletRules_MergeUnclaimedDevelopmentFundCouponsResult
	nonconsuming choice AmuletRules_MergeUnclaimedDevelopmentFundCoupons : AmuletRules_MergeUnclaimedDevelopmentFundCouponsResult
	-- ^ Batch merge of unclaimed development fund coupons

this way they show as docs here: https://docs.dev.sync.global/app_dev/api/splice-amulet/Splice-AmuletRules.html#type-splice-amuletrules-amuletrulescreateexternalpartysetupproposal-53882

[meiersi-da]

also apply to other choices you've added

[jose-velasco-ieu]

done