Add claim contract for weight-based fund distribution

[p-offtermatt]

Summary

• New claim contract: admin creates distributions by sending funds with (address, weight) pairs
• Users call Claim to receive their proportional share across all active distributions (multi-denom)
• Expired distributions can be swept by anyone, returning unclaimed funds to a configured treasury
• Duplicate addresses in claims are accumulated (not overwritten), expired entries are lazily cleaned up, and storage errors are properly propagated

Test plan

• 14 unit tests covering all execute/query paths
• Run make compile to generate WASM artifact
• Run make schema to generate JSON schemas and TS types

[Copilot]

Pull request overview

Introduces a new CosmWasm claim contract that lets an admin create weight-based, multi-denom distributions with expiry, enabling users to claim their proportional share and allowing expired distributions to be swept to a treasury.

Changes:

• Adds the claim contract (instantiate/execute/query), including state, messages, errors, and schema generation.
• Implements create-distribution, multi-distribution claiming, expiry checks, and sweep-to-treasury behavior.
• Adds unit tests and wires the contract into the workspace + make schema flow.

Reviewed changes

Copilot reviewed 11 out of 13 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
contracts/claim/src/contract.rs	Core contract logic for creating distributions, claiming across active distributions, sweeping expired funds, and queries.
contracts/claim/src/state.rs	Defines on-chain storage layout for config, distributions, and per-user claims.
contracts/claim/src/msg.rs	Instantiate/execute message types (CreateDistribution, Claim, SweepExpired, UpdateConfig).
contracts/claim/src/query.rs	Query message types and response structs (config, distribution, pending claims).
contracts/claim/src/error.rs	ContractError definitions for execution failures.
contracts/claim/src/lib.rs	Crate module wiring and test module inclusion.
contracts/claim/src/testing.rs	Unit tests covering main execute/query paths and edge behaviors.
contracts/claim/src/bin/claim_schema.rs	Schema generation entrypoint for make schema.
contracts/claim/Cargo.toml	New contract crate manifest and dependencies.
Cargo.toml	Adds contracts/claim to the workspace members.
Makefile	Includes claim schema generation + TS codegen target for the new contract.
.changelog/unreleased/features/claim-contract.md	Changelog entry for the new claim contract feature.

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[claude]

PR Review: Add claim contract for weight-based fund distribution

Overall this is a well-structured new contract with good test coverage and clear separation of concerns. A few issues worth addressing before merge:

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BUGS / CORRECTNESS

1. Redundant addr_validate in execute_create_distribution (contract.rs:86-101)

Addresses are validated once when building weight_by_addr, then validated again needlessly when writing to CLAIMS. Since the keys of weight_by_addr are already canonical Addr::to_string() values, the second call to addr_validate is wasted work. Use Addr::unchecked(addr_str) or restructure weight_by_addr to store Addr directly.

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2. DistributionAlreadySwept fires even when all funds were legitimately claimed (contract.rs:202-206)

If all recipients claimed before expiry, remaining_funds will be empty and this error fires — even though no sweep ever occurred. The error message is misleading. Consider a dedicated already_swept: bool flag on Distribution, or rename the error to NoRemainingFunds.

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3. Missing migrate entry point

CLAUDE.md states that the migration entrypoint must be implemented in migrate.rs. This contract has no migrate function. Even a passthrough migration should be present for upgradeability.

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GAS / SCALABILITY

4. Unbounded iteration in execute_claim and query_pending_claims

Both functions iterate over all distributions for a user in a single tx/query. If a user accumulates claims across many distributions, this will eventually exceed gas limits. Adding an optional limit / start_after pagination parameter to both Claim {} and PendingClaims {} would make the contract production-safe.

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STATE MANAGEMENT

5. SweepExpired does not clean up stale CLAIMS entries

After SweepExpired is called, CLAIMS entries for that distribution remain in storage indefinitely. They are lazily removed only if the user later calls Claim, but users who never call Claim leave orphaned storage entries. Consider removing claims as part of the sweep (requires iterating the prefix), or at minimum document this trade-off.

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MISSING TEST COVERAGE

The following error paths have no tests:

Error	Trigger
ContractError::EmptyClaims	CreateDistribution { claims: vec![] }
ContractError::ZeroTotalWeight	All ClaimEntry weights are zero
ContractError::ExpiryInPast	expiry <= env.block.time
ContractError::DistributionNotFound	SweepExpired on non-existent id
ContractError::Unauthorized	UpdateConfig called by non-admin

Also worth adding: a test confirming the 'all claimed before expiry' path, which currently triggers the misleading DistributionAlreadySwept error (see point 2 above).

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MINOR

6. No way to enumerate distributions. There is no AllDistributions or paginated list query. Offchain tooling and sweep-callers have no way to discover which distribution IDs exist without tracking events. A ListDistributions { start_after, limit } query would be useful.

7. execute_sweep_expired attributes do not include amounts swept. Adding .add_attribute("amount", ...) to the sweep response would make it easier to audit sweep activity from event logs.

8. Distribution IDs start at 0. Starting at 1 is a common convention and avoids 0 being misread as a sentinel/default value in error messages and tooling.

[dusan-maksimovic]

Except from minor things, LGTM.