Migrate to go-git/go-git v5.0.0 (#10735)

vendor/golang.org/x/crypto/openpgp/packet/packet.go

@@ -14,6 +14,7 @@ import (
 	"crypto/rsa"
 	"io"
 	"math/big"
+	"math/bits"
 
 	"golang.org/x/crypto/cast5"
 	"golang.org/x/crypto/openpgp/errors"
@@ -100,33 +101,65 @@ func (r *partialLengthReader) Read(p []byte) (n int, err error) {
 type partialLengthWriter struct {
 	w          io.WriteCloser
 	lengthByte [1]byte
+	sentFirst  bool
+	buf        []byte
 }
 
+// RFC 4880 4.2.2.4: the first partial length MUST be at least 512 octets long.
+const minFirstPartialWrite = 512
+
 func (w *partialLengthWriter) Write(p []byte) (n int, err error) {
-	for len(p) > 0 {
-		for power := uint(14); power < 32; power-- {
-			l := 1 << power
-			if len(p) >= l {
-				w.lengthByte[0] = 224 + uint8(power)
-				_, err = w.w.Write(w.lengthByte[:])
-				if err != nil {
-					return
-				}
-				var m int
-				m, err = w.w.Write(p[:l])
-				n += m
-				if err != nil {
-					return
-				}
-				p = p[l:]
-				break
+	off := 0
+	if !w.sentFirst {
+		if len(w.buf) > 0 || len(p) < minFirstPartialWrite {
+			off = len(w.buf)
+			w.buf = append(w.buf, p...)
+			if len(w.buf) < minFirstPartialWrite {
+				return len(p), nil
 			}
+			p = w.buf
+			w.buf = nil
 		}
+		w.sentFirst = true
 	}
-	return
+
+	power := uint8(30)
+	for len(p) > 0 {
+		l := 1 << power
+		if len(p) < l {
+			power = uint8(bits.Len32(uint32(len(p)))) - 1
+			l = 1 << power
+		}
+		w.lengthByte[0] = 224 + power
+		_, err = w.w.Write(w.lengthByte[:])
+		if err == nil {
+			var m int
+			m, err = w.w.Write(p[:l])
+			n += m
+		}
+		if err != nil {
+			if n < off {
+				return 0, err
+			}
+			return n - off, err
+		}
+		p = p[l:]
+	}
+	return n - off, nil
 }
 
 func (w *partialLengthWriter) Close() error {
+	if len(w.buf) > 0 {
+		// In this case we can't send a 512 byte packet.
+		// Just send what we have.
+		p := w.buf
+		w.sentFirst = true
+		w.buf = nil
+		if _, err := w.Write(p); err != nil {
+			return err
+		}
+	}
+
 	w.lengthByte[0] = 0
 	_, err := w.w.Write(w.lengthByte[:])
 	if err != nil {