common/hexutil: allow empty strings when decoding JSON (ethereum#3559)

fjl · web-flow · commit 01f6f2d741e7 · 2017-01-13T09:45:40.000+01:00
diff --git a/common/hexutil/json.go b/common/hexutil/json.go
@@ -237,7 +237,7 @@ func checkJSON(input []byte) (raw []byte, err error) {
 		return nil, errNonString
 	}
 	if len(input) == 2 {
-		return nil, ErrEmptyString
+		return nil, nil // empty strings are allowed
 	}
 	if !bytesHave0xPrefix(input[1:]) {
 		return nil, ErrMissingPrefix
@@ -255,7 +255,7 @@ func checkNumberJSON(input []byte) (raw []byte, err error) {
 	}
 	input = input[1 : len(input)-1]
 	if len(input) == 0 {
-		return nil, ErrEmptyString
+		return nil, nil // empty strings are allowed
 	}
 	if !bytesHave0xPrefix(input) {
 		return nil, ErrMissingPrefix
diff --git a/common/hexutil/json_test.go b/common/hexutil/json_test.go
@@ -60,13 +60,13 @@ var unmarshalBytesTests = []unmarshalTest{
 	{input: "", wantErr: errNonString},
 	{input: "null", wantErr: errNonString},
 	{input: "10", wantErr: errNonString},
-	{input: `""`, wantErr: ErrEmptyString},
 	{input: `"0"`, wantErr: ErrMissingPrefix},
 	{input: `"0x0"`, wantErr: ErrOddLength},
 	{input: `"0xxx"`, wantErr: ErrSyntax},
 	{input: `"0x01zz01"`, wantErr: ErrSyntax},
 
 	// valid encoding
+	{input: `""`, want: referenceBytes("")},
 	{input: `"0x"`, want: referenceBytes("")},
 	{input: `"0x02"`, want: referenceBytes("02")},
 	{input: `"0X02"`, want: referenceBytes("02")},
@@ -125,14 +125,14 @@ var unmarshalBigTests = []unmarshalTest{
 	{input: "", wantErr: errNonString},
 	{input: "null", wantErr: errNonString},
 	{input: "10", wantErr: errNonString},
-	{input: `""`, wantErr: ErrEmptyString},
 	{input: `"0"`, wantErr: ErrMissingPrefix},
 	{input: `"0x"`, wantErr: ErrEmptyNumber},
 	{input: `"0x01"`, wantErr: ErrLeadingZero},
 	{input: `"0xx"`, wantErr: ErrSyntax},
 	{input: `"0x1zz01"`, wantErr: ErrSyntax},
 
 	// valid encoding
+	{input: `""`, want: big.NewInt(0)},
 	{input: `"0x0"`, want: big.NewInt(0)},
 	{input: `"0x2"`, want: big.NewInt(0x2)},
 	{input: `"0x2F2"`, want: big.NewInt(0x2f2)},
@@ -198,7 +198,6 @@ var unmarshalUint64Tests = []unmarshalTest{
 	{input: "", wantErr: errNonString},
 	{input: "null", wantErr: errNonString},
 	{input: "10", wantErr: errNonString},
-	{input: `""`, wantErr: ErrEmptyString},
 	{input: `"0"`, wantErr: ErrMissingPrefix},
 	{input: `"0x"`, wantErr: ErrEmptyNumber},
 	{input: `"0x01"`, wantErr: ErrLeadingZero},
@@ -207,6 +206,7 @@ var unmarshalUint64Tests = []unmarshalTest{
 	{input: `"0x1zz01"`, wantErr: ErrSyntax},
 
 	// valid encoding
+	{input: `""`, want: uint64(0)},
 	{input: `"0x0"`, want: uint64(0)},
 	{input: `"0x2"`, want: uint64(0x2)},
 	{input: `"0x2F2"`, want: uint64(0x2f2)},

Original file line number	Diff line number	Diff line change
`@@ -237,7 +237,7 @@ func checkJSON(input []byte) (raw []byte, err error) {`
`237`	`237`	`return nil, errNonString`
`238`	`238`	`}`
`239`	`239`	`if len(input) == 2 {`
`240`		`- return nil, ErrEmptyString`
	`240`	`+ return nil, nil // empty strings are allowed`
`241`	`241`	`}`
`242`	`242`	`if !bytesHave0xPrefix(input[1:]) {`
`243`	`243`	`return nil, ErrMissingPrefix`
`@@ -255,7 +255,7 @@ func checkNumberJSON(input []byte) (raw []byte, err error) {`
`255`	`255`	`}`
`256`	`256`	`input = input[1 : len(input)-1]`
`257`	`257`	`if len(input) == 0 {`
`258`		`- return nil, ErrEmptyString`
	`258`	`+ return nil, nil // empty strings are allowed`
`259`	`259`	`}`
`260`	`260`	`if !bytesHave0xPrefix(input) {`
`261`	`261`	`return nil, ErrMissingPrefix`