Merge branch 'master' into jc/commit-ammend

1 files changed, 32 insertions, 10 deletions

diff --git a/plumbing/format/packfile/parser.go b/plumbing/format/packfile/parser.go
index ee5c289..edbc0e7 100644
--- a/plumbing/format/packfile/parser.go
+++ b/plumbing/format/packfile/parser.go
@@ -4,12 +4,12 @@ import (
 	"bytes"
 	"errors"
 	"io"
-	stdioutil "io/ioutil"
 
 	"github.com/go-git/go-git/v5/plumbing"
 	"github.com/go-git/go-git/v5/plumbing/cache"
 	"github.com/go-git/go-git/v5/plumbing/storer"
 	"github.com/go-git/go-git/v5/utils/ioutil"
+	"github.com/go-git/go-git/v5/utils/sync"
 )
 
 var (
@@ -175,7 +175,8 @@ func (p *Parser) init() error {
 }
 
 func (p *Parser) indexObjects() error {
-	buf := new(bytes.Buffer)
+	buf := sync.GetBytesBuffer()
+	defer sync.PutBytesBuffer(buf)
 
 	for i := uint32(0); i < p.count; i++ {
 		buf.Reset()
@@ -219,6 +220,7 @@ func (p *Parser) indexObjects() error {
 			ota = newBaseObject(oh.Offset, oh.Length, t)
 		}
 
+		buf.Grow(int(oh.Length))
 		_, crc, err := p.scanner.NextObject(buf)
 		if err != nil {
 			return err
@@ -234,6 +236,15 @@ func (p *Parser) indexObjects() error {
 				return err
 			}
 
+			// Move children of placeholder parent into actual parent, in case this
+			// was a non-external delta reference.
+			if placeholder, ok := p.oiByHash[sha1]; ok {
+				ota.Children = placeholder.Children
+				for _, c := range ota.Children {
+					c.Parent = ota
+				}
+			}
+
 			ota.SHA1 = sha1
 			p.oiByHash[ota.SHA1] = ota
 		}
@@ -264,7 +275,9 @@ func (p *Parser) indexObjects() error {
 }
 
 func (p *Parser) resolveDeltas() error {
-	buf := &bytes.Buffer{}
+	buf := sync.GetBytesBuffer()
+	defer sync.PutBytesBuffer(buf)
+
 	for _, obj := range p.oi {
 		buf.Reset()
 		err := p.get(obj, buf)
@@ -283,9 +296,10 @@ func (p *Parser) resolveDeltas() error {
 
 		if !obj.IsDelta() && len(obj.Children) > 0 {
 			for _, child := range obj.Children {
-				if err := p.resolveObject(stdioutil.Discard, child, content); err != nil {
+				if err := p.resolveObject(io.Discard, child, content); err != nil {
 					return err
 				}
+				p.resolveExternalRef(child)
 			}
 
 			// Remove the delta from the cache.
@@ -298,6 +312,16 @@ func (p *Parser) resolveDeltas() error {
 	return nil
 }
 
+func (p *Parser) resolveExternalRef(o *objectInfo) {
+	if ref, ok := p.oiByHash[o.SHA1]; ok && ref.ExternalRef {
+		p.oiByHash[o.SHA1] = o
+		o.Children = ref.Children
+		for _, c := range o.Children {
+			c.Parent = o
+		}
+	}
+}
+
 func (p *Parser) get(o *objectInfo, buf *bytes.Buffer) (err error) {
 	if !o.ExternalRef { // skip cache check for placeholder parents
 		b, ok := p.cache.Get(o.Offset)
@@ -335,9 +359,8 @@ func (p *Parser) get(o *objectInfo, buf *bytes.Buffer) (err error) {
 	}
 
 	if o.DiskType.IsDelta() {
-		b := bufPool.Get().(*bytes.Buffer)
-		defer bufPool.Put(b)
-		b.Reset()
+		b := sync.GetBytesBuffer()
+		defer sync.PutBytesBuffer(b)
 		err := p.get(o.Parent, b)
 		if err != nil {
 			return err
@@ -371,9 +394,8 @@ func (p *Parser) resolveObject(
 	if !o.DiskType.IsDelta() {
 		return nil
 	}
-	buf := bufPool.Get().(*bytes.Buffer)
-	defer bufPool.Put(buf)
-	buf.Reset()
+	buf := sync.GetBytesBuffer()
+	defer sync.PutBytesBuffer(buf)
 	err := p.readData(buf, o)
 	if err != nil {
 		return err