feat: implement MaxSupply (#1319)

## Description

This implements one of the token safety parameters on the leverage checklist.

closes: #1227

---

### Author Checklist

- [x] included the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [x] added `!` to the type prefix if API or client breaking change
- [x] added appropriate labels to the PR
- [x] targeted the correct branch (see [PR Targeting](https://github.com/umee-network/umee/blob/main/CONTRIBUTING.md#pr-targeting))
- [x] provided a link to the relevant issue or specification
- [x] added a changelog entry to `CHANGELOG.md`
- [x] included comments for [documenting Go code](https://blog.golang.org/godoc)
- [ ] updated the relevant documentation or specification
- [x] reviewed "Files changed" and left comments if necessary
- [x] confirmed all CI checks have passed

CHANGELOG.md

@@ -90,6 +90,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 - [1323](https://github.com/umee-network/umee/pull/1323) Oracle cli - Add validator address override option.
 - [1329](https://github.com/umee-network/umee/pull/1329) Implement MaxCollateralShare.
 - [1330](https://github.com/umee-network/umee/pull/1330) Implemented MaxSupplyUtilization.
+- [1319](https://github.com/umee-network/umee/pull/1319) Implemented MaxSupply.
 - [1331](https://github.com/umee-network/umee/pull/1331) Implemented MinCollateralLiquidity.
 
 ### Improvements

x/leverage/fixtures/token.go

@@ -31,6 +31,6 @@ func Token(base, symbol string) types.Token {
 		MaxCollateralShare:     sdk.MustNewDecFromStr("1"),
 		MaxSupplyUtilization:   sdk.MustNewDecFromStr("0.9"),
 		MinCollateralLiquidity: sdk.MustNewDecFromStr("0"),
-		MaxSupply:              sdk.NewInt(100000000000),
+		MaxSupply:              sdk.NewInt(100_000_000000),
 	}
 }

x/leverage/keeper/keeper.go

@@ -83,6 +83,21 @@ func (k Keeper) Supply(ctx sdk.Context, supplierAddr sdk.AccAddress, coin sdk.Co
 		return sdk.Coin{}, err
 	}
 
+	token, err := k.GetTokenSettings(ctx, coin.Denom)
+	if err != nil {
+		return sdk.Coin{}, err
+	}
+
+	total, err := k.GetTotalSupply(ctx, coin.Denom)
+	if err != nil {
+		return sdk.Coin{}, err
+	}
+
+	if token.MaxSupply.IsPositive() && total.Add(coin).Amount.GTE(token.MaxSupply) {
+		return sdk.Coin{}, types.ErrMaxSupply.Wrapf("attempted: %s, current supply: %s, max supply: %s",
+			coin, total.Amount, token.MaxSupply)
+	}
+
 	// determine uToken amount to mint
 	uToken, err := k.ExchangeToken(ctx, coin)
 	if err != nil {

x/leverage/keeper/keeper_test.go

@@ -28,6 +28,9 @@ func (s *IntegrationTestSuite) TestSupply() {
 	s.borrow(borrower, coin(atomDenom, 10_000000))
 	s.tk.SetBorrow(ctx, borrower, coin(atomDenom, 60_000000))
 
+	// create a supplier that will exceed token's default MaxSupply
+	whale := s.newAccount(coin(umeeDenom, 1_000_000_000000))
+
 	tcs := []testCase{
 		{
 			"unregistered denom",
@@ -78,6 +81,13 @@ func (s *IntegrationTestSuite) TestSupply() {
 			coin("u/"+atomDenom, 40_000000),
 			nil,
 		},
+		{
+			"max supply",
+			whale,
+			coin(umeeDenom, 1_000_000_000000),
+			sdk.Coin{},
+			types.ErrMaxSupply,
+		},
 	}
 
 	for _, tc := range tcs {

x/leverage/types/errors.go

@@ -37,6 +37,7 @@ var (
 	ErrMaxSupplyUtilization    = sdkerrors.Register(ModuleName, 501, "market would exceed MaxSupplyUtilization")
 	ErrMinCollateralLiquidity  = sdkerrors.Register(ModuleName, 502, "market would fall below MinCollateralLiquidity")
 	ErrMaxCollateralShare      = sdkerrors.Register(ModuleName, 503, "market would exceed MaxCollateralShare")
+	ErrMaxSupply               = sdkerrors.Register(ModuleName, 504, "market would exceed MaxSupply")
 
 	// 6XX = Internal Failsafes
 	ErrInvalidUtilization      = sdkerrors.Register(ModuleName, 600, "invalid token utilization")