feat(math): Add mutative api for NewIntFromBigInt (#18030)

math/CHANGELOG.md

@@ -40,6 +40,7 @@ Ref: https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.j
 
 * [#18247](https://github.com/cosmos/cosmos-sdk/pull/18247) Add mutative api for Uint.BigInt()
 * [#17803](https://github.com/cosmos/cosmos-sdk/pull/17803) Add mutative api for Int.BigInt()
+* [#18030](https://github.com/cosmos/cosmos-sdk/pull/18030) Add mutative api for NewIntFromBigInt
 
 ### Bug Fixes
 

math/int.go

@@ -126,6 +126,21 @@ func NewIntFromBigInt(i *big.Int) Int {
 	return Int{new(big.Int).Set(i)}
 }
 
+// NewIntFromBigIntMut constructs Int from big.Int. If the provided big.Int is nil,
+// it returns an empty instance. This function panics if the bit length is > 256.
+// Note, this function mutate the argument.
+func NewIntFromBigIntMut(i *big.Int) Int {
+	if i == nil {
+		return Int{}
+	}
+
+	if i.BitLen() > MaxBitLen {
+		panic("NewIntFromBigInt() out of bound")
+	}
+
+	return Int{i}
+}
+
 // NewIntFromString constructs Int from string
 func NewIntFromString(s string) (res Int, ok bool) {
 	i, ok := newIntegerFromString(s)

math/int_test.go

@@ -56,6 +56,24 @@ func (s *intTestSuite) TestNewIntFromBigInt() {
 	s.Require().NotEqual(r, i.BigInt())
 }
 
+func (s *intTestSuite) TestNewIntFromBigIntMut() {
+	im := math.NewIntFromBigIntMut(nil)
+	s.Require().True(im.IsNil())
+
+	r := big.NewInt(42)
+	im = math.NewIntFromBigIntMut(r)
+	s.Require().Equal(r, im.BigInt())
+
+	// Compare value of NewIntFromBigInt and NewIntFromBigIntMut
+	i := math.NewIntFromBigInt(r)
+	s.Require().Equal(i, im)
+
+	// modify r and ensure i doesn't change & im changes
+	r = r.SetInt64(100)
+	s.Require().NotEqual(r, i.BigInt())
+	s.Require().Equal(r, im.BigInt())
+}
+
 func (s *intTestSuite) TestConvertToBigIntMutative() {
 	r := big.NewInt(42)
 	i := math.NewIntFromBigInt(r)