vendor: update buildkit to opentelemetry support

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/github.com/klauspost/compress/zstd/decoder.go

@@ -5,7 +5,6 @@
 package zstd
 
 import (
-	"bytes"
 	"errors"
 	"io"
 	"sync"
@@ -85,6 +84,10 @@ func NewReader(r io.Reader, opts ...DOption) (*Decoder, error) {
 	d.current.output = make(chan decodeOutput, d.o.concurrent)
 	d.current.flushed = true
 
+	if r == nil {
+		d.current.err = ErrDecoderNilInput
+	}
+
 	// Transfer option dicts.
 	d.dicts = make(map[uint32]dict, len(d.o.dicts))
 	for _, dc := range d.o.dicts {
@@ -111,7 +114,7 @@ func NewReader(r io.Reader, opts ...DOption) (*Decoder, error) {
 // When the stream is done, io.EOF will be returned.
 func (d *Decoder) Read(p []byte) (int, error) {
 	if d.stream == nil {
-		return 0, errors.New("no input has been initialized")
+		return 0, ErrDecoderNilInput
 	}
 	var n int
 	for {
@@ -152,12 +155,20 @@ func (d *Decoder) Read(p []byte) (int, error) {
 
 // Reset will reset the decoder the supplied stream after the current has finished processing.
 // Note that this functionality cannot be used after Close has been called.
+// Reset can be called with a nil reader to release references to the previous reader.
+// After being called with a nil reader, no other operations than Reset or DecodeAll or Close
+// should be used.
 func (d *Decoder) Reset(r io.Reader) error {
 	if d.current.err == ErrDecoderClosed {
 		return d.current.err
 	}
+
+	d.drainOutput()
+
 	if r == nil {
-		return errors.New("nil Reader sent as input")
+		d.current.err = ErrDecoderNilInput
+		d.current.flushed = true
+		return nil
 	}
 
 	if d.stream == nil {
@@ -166,14 +177,13 @@ func (d *Decoder) Reset(r io.Reader) error {
 		go d.startStreamDecoder(d.stream)
 	}
 
-	d.drainOutput()
-
 	// If bytes buffer and < 1MB, do sync decoding anyway.
-	if bb, ok := r.(*bytes.Buffer); ok && bb.Len() < 1<<20 {
+	if bb, ok := r.(byter); ok && bb.Len() < 1<<20 {
+		bb2 := bb
 		if debug {
 			println("*bytes.Buffer detected, doing sync decode, len:", bb.Len())
 		}
-		b := bb.Bytes()
+		b := bb2.Bytes()
 		var dst []byte
 		if cap(d.current.b) > 0 {
 			dst = d.current.b
@@ -226,20 +236,17 @@ func (d *Decoder) drainOutput() {
 		println("current already flushed")
 		return
 	}
-	for {
-		select {
-		case v := <-d.current.output:
-			if v.d != nil {
-				if debug {
-					printf("re-adding decoder %p", v.d)
-				}
-				d.decoders <- v.d
-			}
-			if v.err == errEndOfStream {
-				println("current flushed")
-				d.current.flushed = true
-				return
+	for v := range d.current.output {
+		if v.d != nil {
+			if debug {
+				printf("re-adding decoder %p", v.d)
 			}
+			d.decoders <- v.d
+		}
+		if v.err == errEndOfStream {
+			println("current flushed")
+			d.current.flushed = true
+			return
 		}
 	}
 }
@@ -249,7 +256,7 @@ func (d *Decoder) drainOutput() {
 // Any error encountered during the write is also returned.
 func (d *Decoder) WriteTo(w io.Writer) (int64, error) {
 	if d.stream == nil {
-		return 0, errors.New("no input has been initialized")
+		return 0, ErrDecoderNilInput
 	}
 	var n int64
 	for {