Add Kamino/Solend-style lending program example#44
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A finance/lending Anchor example implementing the core techniques of the most-used Solana lending protocols: - Per-asset reserves with a program-owned liquidity vault and a share-token mint; the share/liquidity exchange rate rises as interest accrues. - Utilization-based kinked interest-rate curve compounded through a cumulative borrow-rate index, with per-obligation scaled debt. - Per-borrower obligations: post share-token collateral, borrow against it up to a loan-to-value limit, repay, withdraw. - Oracle-priced health and close-factor-capped liquidation with a seize bonus. - Switchboard-On-Demand-shaped price feed with a set_price test writer. - Integer-only u128 math (no floats/fixed-point), rounding always in the protocol's favour; available_liquidity as source of truth defeats the empty-pool share-inflation attack. Rust + LiteSVM tests cover supply/redeem, borrow/repay, withdraw, interest accrual, liquidation, the inflation guard, stale reserve/price rejection, and rounding edges (18 tests). https://claude.ai/code/session_01RwE8f8ahP5S6SDNTsXmpj9
`anchor build`'s IDL generation compiles a generated test under the
idl-build feature, where the `#[constant]` macro mis-evaluates the 1e18
u128 literal as i32 ("literal out of range for i32"), failing CI. These
values don't need to be in the IDL, so they're plain `pub const`s now.
https://claude.ai/code/session_01RwE8f8ahP5S6SDNTsXmpj9
A Quasar (zero-copy, no_std) port of finance/lending, mirroring the shipped Quasar escrow/vault examples' fixed-size-account idiom: - Isolated single-collateral / single-borrow obligations (fixed-size accounts) rather than the Anchor version's Vec-based multi-asset obligation. Quasar does support Vec<T, N> and CtxWithRemaining, but the DeFi examples favour fixed-size positions, so this follows that idiom. - Interest accrues inline per instruction instead of via a separate refresh. - Keeps every core technique: share-token deposits, a kinked-curve cumulative interest index, oracle-priced health, and close-factor liquidation with a bonus. - Integer-only u128 math scaled by 1e18, rounding in the protocol's favour. quasar-svm tests cover supply/redeem, borrow up to the LTV limit (and rejection beyond), repay, interest accrual lifting share value, and liquidation of an unhealthy position with the healthy path rejected. https://claude.ai/code/session_01RwE8f8ahP5S6SDNTsXmpj9
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What
A new
finance/lending/anchorexample: a Kamino/Solend-style borrow/lend program built with the techniques the most-used Solana lending protocols share.How it works
deposit_reserve_liquidityto mint share tokens; the share/liquidity exchange rate rises as interest accrues, soredeem_reserve_collateralreturns more than was deposited.available_liquidity(not the vault's raw balance) is the source of truth, which defeats the empty-pool share-inflation attack.min/optimal/maxborrow rate aroundoptimal_utilization) compounded through a cumulative borrow-rate index advanced byrefresh_reserve. Each borrow stores scaled debt (principal ÷ index at borrow time), so every obligation's debt grows automatically.refresh_obligationrecomputesborrowed_value,allowed_borrow_value(Σ collateral × LTV) andunhealthy_borrow_value(Σ collateral × liquidation threshold) from oracle prices.borrow_obligation_liquidity/withdraw_obligation_collateralare gated by the LTV limit;liquidate_obligationrepays an unhealthy obligation's debt (capped by the close factor) and seizes collateral plus a bonus.PriceFeedmirrors a Switchboard On-Demand pull feed (mantissa + exponent + slot); aset_pricehandler writes it directly for deterministic LiteSVM tests, with the production Switchboard mapping documented in the README. Freshness is checked in slots.u128(no floats, no fixed-point crates), ratios scaled byFIXED_POINT_SCALE(10^18), every conversion rounding in the protocol's favour.A worked directional-short example (supply USDC, borrow + sell NVDAx, pay a variable rate, buy back, repay) is in the README.
Tests
Rust + LiteSVM, run with
cargo test(Anchor'sanchor test). 18 tests across 6 files cover supply/redeem, borrow/repay, withdraw, interest accrual, liquidation with bonus and close-factor cap, the inflation guard, stale reserve/price rejection, and rounding/health-boundary edges.anchor build(orcargo build-sbf) must run first so the tests can load the compiled.so.https://claude.ai/code/session_01RwE8f8ahP5S6SDNTsXmpj9
Generated by Claude Code