*: Add missing error checks

Some areas of the code base were missing error checks,
without them it may be harder to troubleshoot unexpected
behaviours.

Signed-off-by: Paulo Gomes <pjbgf@linux.com>

2 files changed, 24 insertions, 14 deletions

diff --git a/plumbing/format/idxfile/writer.go b/plumbing/format/idxfile/writer.go
index e556013..c4c21e1 100644
--- a/plumbing/format/idxfile/writer.go
+++ b/plumbing/format/idxfile/writer.go
@@ -136,15 +136,23 @@ func (w *Writer) createIndex() (*MemoryIndex, error) {
 
 		offset := o.Offset
 		if offset > math.MaxInt32 {
-			offset = w.addOffset64(offset)
+			var err error
+			offset, err = w.addOffset64(offset)
+			if err != nil {
+				return nil, err
+			}
 		}
 
 		buf.Truncate(0)
-		binary.WriteUint32(buf, uint32(offset))
+		if err := binary.WriteUint32(buf, uint32(offset)); err != nil {
+			return nil, err
+		}
 		idx.Offset32[bucket] = append(idx.Offset32[bucket], buf.Bytes()...)
 
 		buf.Truncate(0)
-		binary.WriteUint32(buf, o.CRC32)
+		if err := binary.WriteUint32(buf, o.CRC32); err != nil {
+			return nil, err
+		}
 		idx.CRC32[bucket] = append(idx.CRC32[bucket], buf.Bytes()...)
 	}
 
@@ -158,15 +166,17 @@ func (w *Writer) createIndex() (*MemoryIndex, error) {
 	return idx, nil
 }
 
-func (w *Writer) addOffset64(pos uint64) uint64 {
+func (w *Writer) addOffset64(pos uint64) (uint64, error) {
 	buf := new(bytes.Buffer)
-	binary.WriteUint64(buf, pos)
-	w.index.Offset64 = append(w.index.Offset64, buf.Bytes()...)
+	if err := binary.WriteUint64(buf, pos); err != nil {
+		return 0, err
+	}
 
+	w.index.Offset64 = append(w.index.Offset64, buf.Bytes()...)
 	index := uint64(w.offset64 | (1 << 31))
 	w.offset64++
 
-	return index
+	return index, nil
 }
 
 func (o objects) Len() int {
diff --git a/plumbing/protocol/packp/advrefs.go b/plumbing/protocol/packp/advrefs.go
index 1bd724c..f93ad30 100644
--- a/plumbing/protocol/packp/advrefs.go
+++ b/plumbing/protocol/packp/advrefs.go
@@ -57,7 +57,7 @@ func (a *AdvRefs) AddReference(r *plumbing.Reference) error {
 	switch r.Type() {
 	case plumbing.SymbolicReference:
 		v := fmt.Sprintf("%s:%s", r.Name().String(), r.Target().String())
-		a.Capabilities.Add(capability.SymRef, v)
+		return a.Capabilities.Add(capability.SymRef, v)
 	case plumbing.HashReference:
 		a.References[r.Name().String()] = r.Hash()
 	default:
@@ -96,12 +96,12 @@ func (a *AdvRefs) addRefs(s storer.ReferenceStorer) error {
 //
 // Git versions prior to 1.8.4.3 has an special procedure to get
 // the reference where is pointing to HEAD:
-// - Check if a reference called master exists. If exists and it
-//	 has the same hash as HEAD hash, we can say that HEAD is pointing to master
-// - If master does not exists or does not have the same hash as HEAD,
-//   order references and check in that order if that reference has the same
-//   hash than HEAD. If yes, set HEAD pointing to that branch hash
-// - If no reference is found, throw an error
+//   - Check if a reference called master exists. If exists and it
+//     has the same hash as HEAD hash, we can say that HEAD is pointing to master
+//   - If master does not exists or does not have the same hash as HEAD,
+//     order references and check in that order if that reference has the same
+//     hash than HEAD. If yes, set HEAD pointing to that branch hash
+//   - If no reference is found, throw an error
 func (a *AdvRefs) resolveHead(s storer.ReferenceStorer) error {
 	if a.Head == nil {
 		return nil