accounts/abi: Negative numbers not properly converted in ABI encoding

When converting a negative number e.g., -2, the resulting ABI encoding
should look as follows:
fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffe.
However, since the check of the type is for an uint instead of an
int, it results in the following ABI encoding:
0101010101010101010101010101010101010101010101010101010101010102. The
Ethereum ABI
(https://github.com/ethereum/wiki/wiki/Ethereum-Contract-ABI) says,
that signed integers are stored in two's complement which should be
of the form ffffff.... and not 01010101..... for e.g. -1. Thus, I
removed the type check in numbers.go as well as the function S256
as I don't think they are correct. Or maybe I'm missing something?

1 files changed, 3 insertions, 23 deletions

diff --git a/accounts/abi/numbers_test.go b/accounts/abi/numbers_test.go
index d66a43258..f409aa60f 100644
--- a/accounts/abi/numbers_test.go
+++ b/accounts/abi/numbers_test.go
@@ -26,48 +26,28 @@ import (
 func TestNumberTypes(t *testing.T) {
 	ubytes := make([]byte, 32)
 	ubytes[31] = 1
-	sbytesmin := []byte{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}
 
 	unsigned := U256(big.NewInt(1))
 	if !bytes.Equal(unsigned, ubytes) {
 		t.Errorf("expected %x got %x", ubytes, unsigned)
 	}
-
-	signed := S256(big.NewInt(1))
-	if !bytes.Equal(signed, ubytes) {
-		t.Errorf("expected %x got %x", ubytes, unsigned)
-	}
-
-	signed = S256(big.NewInt(-1))
-	if !bytes.Equal(signed, sbytesmin) {
-		t.Errorf("expected %x got %x", ubytes, unsigned)
-	}
 }
 
 func TestPackNumber(t *testing.T) {
 	ubytes := make([]byte, 32)
 	ubytes[31] = 1
-	sbytesmin := []byte{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}
 	maxunsigned := []byte{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255}
 
-	packed := packNum(reflect.ValueOf(1), IntTy)
-	if !bytes.Equal(packed, ubytes) {
-		t.Errorf("expected %x got %x", ubytes, packed)
-	}
-	packed = packNum(reflect.ValueOf(-1), IntTy)
-	if !bytes.Equal(packed, sbytesmin) {
-		t.Errorf("expected %x got %x", ubytes, packed)
-	}
-	packed = packNum(reflect.ValueOf(1), UintTy)
+	packed := packNum(reflect.ValueOf(1))
 	if !bytes.Equal(packed, ubytes) {
 		t.Errorf("expected %x got %x", ubytes, packed)
 	}
-	packed = packNum(reflect.ValueOf(-1), UintTy)
+	packed = packNum(reflect.ValueOf(-1))
 	if !bytes.Equal(packed, maxunsigned) {
 		t.Errorf("expected %x got %x", maxunsigned, packed)
 	}
 
-	packed = packNum(reflect.ValueOf("string"), UintTy)
+	packed = packNum(reflect.ValueOf("string"))
 	if packed != nil {
 		t.Errorf("expected 'string' to pack to nil. got %x instead", packed)
 	}