Fix panic when get editor config file (#36241)

Fix #36239

modules/git/blob_gogit.go

@@ -9,24 +9,38 @@ package git
 import (
 	"io"
 
+	"code.gitea.io/gitea/modules/log"
+
 	"github.com/go-git/go-git/v5/plumbing"
 )
 
 // Blob represents a Git object.
 type Blob struct {
-	ID ObjectID
+	ID   ObjectID
+	repo *Repository
+	name string
+}
 
-	gogitEncodedObj plumbing.EncodedObject
-	name            string
+func (b *Blob) gogitEncodedObj() (plumbing.EncodedObject, error) {
+	return b.repo.gogitRepo.Storer.EncodedObject(plumbing.AnyObject, plumbing.Hash(b.ID.RawValue()))
 }
 
 // DataAsync gets a ReadCloser for the contents of a blob without reading it all.
 // Calling the Close function on the result will discard all unread output.
 func (b *Blob) DataAsync() (io.ReadCloser, error) {
-	return b.gogitEncodedObj.Reader()
+	obj, err := b.gogitEncodedObj()
+	if err != nil {
+		return nil, err
+	}
+	return obj.Reader()
 }
 
 // Size returns the uncompressed size of the blob
 func (b *Blob) Size() int64 {
-	return b.gogitEncodedObj.Size()
+	obj, err := b.gogitEncodedObj()
+	if err != nil {
+		log.Error("Error getting gogit encoded object for blob %s(%s): %v", b.name, b.ID.String(), err)
+		return 0
+	}
+	return obj.Size()
 }