refactor: make marshal errors private

Author: ivokub

internal/generator/ecdsa/template/ecdsa.test.go.tmpl

@@ -82,7 +82,7 @@ func TestNonMalleability(t *testing.T) {
 		bsig := make([]byte, 2*sizeFr+1)
 		var sig Signature
 		_, err := sig.SetBytes(bsig)
-		if err != ErrWrongSize {
+		if err != errWrongSize {
 			t.Fatal("should raise wrong size error")
 		}
 	})
@@ -98,7 +98,7 @@ func TestNonMalleability(t *testing.T) {
 
 		var sig Signature
 		_, err := sig.SetBytes(bsig)
-		if err != ErrRBiggerThanRMod {
+		if err != errRBiggerThanRMod {
 			t.Fatal("should raise error r >= r_mod")
 		}
 	})
@@ -114,7 +114,7 @@ func TestNonMalleability(t *testing.T) {
 
 		var sig Signature
 		_, err := sig.SetBytes(bsig)
-		if err != ErrSBiggerThanRMod {
+		if err != errSBiggerThanRMod {
 			t.Fatal("should raise error s >= r_mod")
 		}
 	})
@@ -130,7 +130,7 @@ func TestNoZeros(t *testing.T) {
 		bts := sig.Bytes()
 		var newSig Signature
 		_, err := newSig.SetBytes(bts)
-		if err != ErrZero {
+		if err != errZero {
 			t.Fatal("expected error for zero R")
 		}
 	})
@@ -142,7 +142,7 @@ func TestNoZeros(t *testing.T) {
 		bts := sig.Bytes()
 		var newSig Signature
 		_, err := newSig.SetBytes(bts)
-		if err != ErrZero {
+		if err != errZero {
 			t.Fatal("expected error for zero S")
 		}
 	})

internal/generator/ecdsa/template/marshal.go.tmpl

@@ -10,10 +10,10 @@ import (
 	{{- end }}
 )
 
-var ErrWrongSize = errors.New("wrong size buffer")
-var ErrRBiggerThanRMod = errors.New("r >= r_mod")
-var ErrSBiggerThanRMod = errors.New("s >= r_mod")
-var ErrZero = errors.New("zero value")
+var errWrongSize = errors.New("wrong size buffer")
+var errRBiggerThanRMod = errors.New("r >= r_mod")
+var errSBiggerThanRMod = errors.New("s >= r_mod")
+var errZero = errors.New("zero value")
 
 // Bytes returns the binary representation of the public key
 // follows https://tools.ietf.org/html/rfc8032#section-3.1
@@ -130,7 +130,7 @@ func (sig *Signature) Bytes() []byte {
 func (sig *Signature) SetBytes(buf []byte) (int, error) {
 	n := 0
 	if len(buf) != sizeSignature {
-		return n, ErrWrongSize
+		return n, errWrongSize
 	}
 
 	// S, R < R_mod (to avoid malleability)
@@ -139,17 +139,17 @@ func (sig *Signature) SetBytes(buf []byte) (int, error) {
 	bufBigInt := new(big.Int)
 	bufBigInt.SetBytes(buf[:sizeFr])
 	if bufBigInt.Cmp(zero) == 0 {
-		return 0, ErrZero
+		return 0, errZero
 	}
 	if bufBigInt.Cmp(frMod) != -1 {
-		return 0, ErrRBiggerThanRMod
+		return 0, errRBiggerThanRMod
 	}
 	bufBigInt.SetBytes(buf[sizeFr : 2*sizeFr])
 	if bufBigInt.Cmp(zero) == 0 {
-		return 0, ErrZero
+		return 0, errZero
 	}
 	if bufBigInt.Cmp(frMod) != -1 {
-		return 0, ErrSBiggerThanRMod
+		return 0, errSBiggerThanRMod
 	}
 
 	subtle.ConstantTimeCopy(1, sig.R[:], buf[:sizeFr])

internal/generator/edwards/eddsa/template/eddsa.test.go.tmpl

@@ -48,7 +48,7 @@ func TestNonMalleability(t *testing.T) {
 		bsig := make([]byte, 2*sizeFr+1)
 		var sig Signature
 		_, err := sig.SetBytes(bsig)
-		if err != ErrWrongSize {
+		if err != errWrongSize {
 			t.Fatal("should raise wrong size error")
 		}
 	})
@@ -66,7 +66,7 @@ func TestNonMalleability(t *testing.T) {
 
 		var sig Signature
 		_, err := sig.SetBytes(bsig)
-		if err != ErrRBiggerThanPMod {
+		if err != errRBiggerThanPMod {
 			t.Fatal("should raise error r >= p_mod")
 		}
 	})
@@ -82,7 +82,7 @@ func TestNonMalleability(t *testing.T) {
 
 		var sig Signature
 		_, err := sig.SetBytes(bsig)
-		if err != ErrSBiggerThanRMod {
+		if err != errSBiggerThanRMod {
 			t.Fatal("should raise error s >= r_mod")
 		}
 	})
@@ -100,7 +100,7 @@ func TestNoZeros(t *testing.T) {
 		bts := sig.Bytes()
 		var newSig Signature
 		_, err := newSig.SetBytes(bts)
-		if err != ErrZero {
+		if err != errZero {
 			t.Fatal("expected error for zero R.Y")
 		}
 	})
@@ -114,7 +114,7 @@ func TestNoZeros(t *testing.T) {
 		bts := sig.Bytes()
 		var newSig Signature
 		_, err := newSig.SetBytes(bts)
-		if err != ErrZero {
+		if err != errZero {
 			t.Fatal("expected error for zero S")
 		}
 	})

internal/generator/edwards/eddsa/template/marshal.go.tmpl

@@ -10,10 +10,10 @@ import (
 // cf point.go (ugly copy)
 const mUnmask = 0x7f
 
-var ErrWrongSize = errors.New("wrong size buffer")
-var ErrSBiggerThanRMod = errors.New("s >= r_mod")
-var ErrRBiggerThanPMod = errors.New("r >= p_mod")
-var ErrZero = errors.New("zero value")
+var errWrongSize = errors.New("wrong size buffer")
+var errSBiggerThanRMod = errors.New("s >= r_mod")
+var errRBiggerThanPMod = errors.New("r >= p_mod")
+var errZero = errors.New("zero value")
 
 // Bytes returns the binary representation of the public key
 // follows https://tools.ietf.org/html/rfc8032#section-3.1
@@ -112,7 +112,7 @@ func (sig *Signature) Bytes() []byte {
 func (sig *Signature) SetBytes(buf []byte) (int, error) {
 	n := 0
 	if len(buf) != sizeSignature {
-		return n, ErrWrongSize
+		return n, errWrongSize
 	}
 
 	// R < P_mod (to avoid malleability)
@@ -127,21 +127,21 @@ func (sig *Signature) SetBytes(buf []byte) (int, error) {
 	bufCopy[0] &= mUnmask
 	bufBigInt.SetBytes(bufCopy)
 	if bufBigInt.Cmp(zero) == 0 {
-		return 0, ErrZero
+		return 0, errZero
 	}
 	if bufBigInt.Cmp(fpMod) != -1 {
-		return 0, ErrRBiggerThanPMod
+		return 0, errRBiggerThanPMod
 	}
 
 	// S < R_mod (to avoid malleability)
 	// R_mod is the relevant group size of the twisted Edwards NOT the fr snark field so it's supposedly smaller
 	bufBigInt.SetBytes(buf[sizeFr : 2*sizeFr])
 	if bufBigInt.Cmp(zero) == 0 {
-		return 0, ErrZero
+		return 0, errZero
 	}
 	cp := twistededwards.GetEdwardsCurve()
 	if bufBigInt.Cmp(&cp.Order) != -1 {
-		return 0, ErrSBiggerThanRMod
+		return 0, errSBiggerThanRMod
 	}
 
 	// deserialisation