Third round of keep-alive aditions

17 files changed, 353 insertions, 122 deletions

diff --git a/merge.go b/merge.go
index b3fd818..bfbf9a3 100644
--- a/merge.go
+++ b/merge.go
@@ -18,10 +18,11 @@ import (
 
 type AnnotatedCommit struct {
 	ptr *C.git_annotated_commit
+	r   *Repository
 }
 
-func newAnnotatedCommitFromC(c *C.git_annotated_commit) *AnnotatedCommit {
-	mh := &AnnotatedCommit{ptr: c}
+func newAnnotatedCommitFromC(ptr *C.git_annotated_commit, r *Repository) *AnnotatedCommit {
+	mh := &AnnotatedCommit{ptr: ptr, r: r}
 	runtime.SetFinalizer(mh, (*AnnotatedCommit).Free)
 	return mh
 }
@@ -32,8 +33,6 @@ func (mh *AnnotatedCommit) Free() {
 }
 
 func (r *Repository) AnnotatedCommitFromFetchHead(branchName string, remoteURL string, oid *Oid) (*AnnotatedCommit, error) {
-	mh := &AnnotatedCommit{}
-
 	cbranchName := C.CString(branchName)
 	defer C.free(unsafe.Pointer(cbranchName))
 
@@ -43,40 +42,41 @@ func (r *Repository) AnnotatedCommitFromFetchHead(branchName string, remoteURL s
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	ret := C.git_annotated_commit_from_fetchhead(&mh.ptr, r.ptr, cbranchName, cremoteURL, oid.toC())
+	var ptr *C.git_annotated_commit
+	ret := C.git_annotated_commit_from_fetchhead(&ptr, r.ptr, cbranchName, cremoteURL, oid.toC())
+	runtime.KeepAlive(oid)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
-	runtime.SetFinalizer(mh, (*AnnotatedCommit).Free)
-	return mh, nil
+
+	return newAnnotatedCommitFromC(ptr, r), nil
 }
 
 func (r *Repository) LookupAnnotatedCommit(oid *Oid) (*AnnotatedCommit, error) {
-	mh := &AnnotatedCommit{}
-
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	ret := C.git_annotated_commit_lookup(&mh.ptr, r.ptr, oid.toC())
+	var ptr *C.git_annotated_commit
+	ret := C.git_annotated_commit_lookup(&ptr, r.ptr, oid.toC())
+	runtime.KeepAlive(oid)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
-	runtime.SetFinalizer(mh, (*AnnotatedCommit).Free)
-	return mh, nil
+	return newAnnotatedCommitFromC(ptr, r), nil
 }
 
 func (r *Repository) AnnotatedCommitFromRef(ref *Reference) (*AnnotatedCommit, error) {
-	mh := &AnnotatedCommit{}
-
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	ret := C.git_annotated_commit_from_ref(&mh.ptr, r.ptr, ref.ptr)
+	var ptr *C.git_annotated_commit
+	ret := C.git_annotated_commit_from_ref(&ptr, r.ptr, ref.ptr)
+	runtime.KeepAlive(r)
+	runtime.KeepAlive(ref)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
-	runtime.SetFinalizer(mh, (*AnnotatedCommit).Free)
-	return mh, nil
+	return newAnnotatedCommitFromC(ptr, r), nil
 }
 
 type MergeTreeFlag int
@@ -162,6 +162,7 @@ func (r *Repository) Merge(theirHeads []*AnnotatedCommit, mergeOptions *MergeOpt
 	}
 	ptr := unsafe.Pointer(&gmerge_head_array[0])
 	err := C.git_merge(r.ptr, (**C.git_annotated_commit)(ptr), C.size_t(len(theirHeads)), cMergeOpts, cCheckoutOpts)
+	runtime.KeepAlive(theirHeads)
 	if err < 0 {
 		return MakeGitError(err)
 	}
@@ -201,6 +202,7 @@ func (r *Repository) MergeAnalysis(theirHeads []*AnnotatedCommit) (MergeAnalysis
 	var analysis C.git_merge_analysis_t
 	var preference C.git_merge_preference_t
 	err := C.git_merge_analysis(&analysis, &preference, r.ptr, (**C.git_annotated_commit)(ptr), C.size_t(len(theirHeads)))
+	runtime.KeepAlive(theirHeads)
 	if err < 0 {
 		return MergeAnalysisNone, MergePreferenceNone, MakeGitError(err)
 	}
@@ -214,14 +216,15 @@ func (r *Repository) MergeCommits(ours *Commit, theirs *Commit, options *MergeOp
 
 	copts := options.toC()
 
-	idx := &Index{}
-
-	ret := C.git_merge_commits(&idx.ptr, r.ptr, ours.cast_ptr, theirs.cast_ptr, copts)
+	var ptr *C.git_index
+	ret := C.git_merge_commits(&ptr, r.ptr, ours.cast_ptr, theirs.cast_ptr, copts)
+	runtime.KeepAlive(ours)
+	runtime.KeepAlive(theirs)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
-	runtime.SetFinalizer(idx, (*Index).Free)
-	return idx, nil
+
+	return newIndexFromC(ptr, r), nil
 }
 
 func (r *Repository) MergeTrees(ancestor *Tree, ours *Tree, theirs *Tree, options *MergeOptions) (*Index, error) {
@@ -230,17 +233,20 @@ func (r *Repository) MergeTrees(ancestor *Tree, ours *Tree, theirs *Tree, option
 
 	copts := options.toC()
 
-	idx := &Index{}
 	var ancestor_ptr *C.git_tree
 	if ancestor != nil {
 		ancestor_ptr = ancestor.cast_ptr
 	}
-	ret := C.git_merge_trees(&idx.ptr, r.ptr, ancestor_ptr, ours.cast_ptr, theirs.cast_ptr, copts)
+	var ptr *C.git_index
+	ret := C.git_merge_trees(&ptr, r.ptr, ancestor_ptr, ours.cast_ptr, theirs.cast_ptr, copts)
+	runtime.KeepAlive(ancestor)
+	runtime.KeepAlive(ours)
+	runtime.KeepAlive(theirs)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
-	runtime.SetFinalizer(idx, (*Index).Free)
-	return idx, nil
+
+	return newIndexFromC(ptr, r), nil
 }
 
 func (r *Repository) MergeBase(one *Oid, two *Oid) (*Oid, error) {
@@ -249,6 +255,9 @@ func (r *Repository) MergeBase(one *Oid, two *Oid) (*Oid, error) {
 
 	var oid C.git_oid
 	ret := C.git_merge_base(&oid, r.ptr, one.toC(), two.toC())
+	runtime.KeepAlive(one)
+	runtime.KeepAlive(two)
+	runtime.KeepAlive(r)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
@@ -265,6 +274,8 @@ func (r *Repository) MergeBases(one, two *Oid) ([]*Oid, error) {
 
 	var coids C.git_oidarray
 	ret := C.git_merge_bases(&coids, r.ptr, one.toC(), two.toC())
+	runtime.KeepAlive(one)
+	runtime.KeepAlive(two)
 	if ret < 0 {
 		return make([]*Oid, 0), MakeGitError(ret)
 	}
@@ -413,6 +424,9 @@ func MergeFile(ancestor MergeFileInput, ours MergeFileInput, theirs MergeFileInp
 		(*C.char)(unsafe.Pointer(oursContents)), C.size_t(len(ours.Contents)), oursPath, C.uint(ours.Mode),
 		(*C.char)(unsafe.Pointer(theirsContents)), C.size_t(len(theirs.Contents)), theirsPath, C.uint(theirs.Mode),
 		copts)
+	runtime.KeepAlive(ancestor)
+	runtime.KeepAlive(ours)
+	runtime.KeepAlive(theirs)
 	if ecode < 0 {
 		return nil, MakeGitError(ecode)
 	}
diff --git a/note.go b/note.go
index a1b15d8..21bed57 100644
--- a/note.go
+++ b/note.go
@@ -52,7 +52,8 @@ func (c *NoteCollection) Create(
 	ret := C.git_note_create(
 		oid.toC(), c.repo.ptr, cref, authorSig,
 		committerSig, id.toC(), cnote, cbool(force))
-
+	runtime.KeepAlive(c)
+	runtime.KeepAlive(id)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
@@ -69,17 +70,18 @@ func (c *NoteCollection) Read(ref string, id *Oid) (*Note, error) {
 		defer C.free(unsafe.Pointer(cref))
 	}
 
-	note := new(Note)
-
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	if ret := C.git_note_read(&note.ptr, c.repo.ptr, cref, id.toC()); ret < 0 {
+	var ptr *C.git_note
+	ret := C.git_note_read(&ptr, c.repo.ptr, cref, id.toC())
+	runtime.KeepAlive(c)
+	runtime.KeepAlive(id)
+	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
 
-	runtime.SetFinalizer(note, (*Note).Free)
-	return note, nil
+	return newNoteFromC(ptr, c.repo), nil
 }
 
 // Remove removes the note for an object
@@ -108,6 +110,8 @@ func (c *NoteCollection) Remove(ref string, author, committer *Signature, id *Oi
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_note_remove(c.repo.ptr, cref, authorSig, committerSig, id.toC())
+	runtime.KeepAlive(c)
+	runtime.KeepAlive(id)
 	if ret < 0 {
 		return MakeGitError(ret)
 	}
@@ -121,8 +125,10 @@ func (c *NoteCollection) DefaultRef() (string, error) {
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	if ret := C.git_note_default_ref(&buf, c.repo.ptr); ret < 0 {
-		return "", MakeGitError(ret)
+	ecode := C.git_note_default_ref(&buf, c.repo.ptr)
+	runtime.KeepAlive(c)
+	if ecode < 0 {
+		return "", MakeGitError(ecode)
 	}
 
 	ret := C.GoString(buf.ptr)
@@ -134,6 +140,13 @@ func (c *NoteCollection) DefaultRef() (string, error) {
 // Note
 type Note struct {
 	ptr *C.git_note
+	r   *Repository
+}
+
+func newNoteFromC(ptr *C.git_note, r *Repository) *Note {
+	note := &Note{ptr: ptr, r: r}
+	runtime.SetFinalizer(note, (*Note).Free)
+	return note
 }
 
 // Free frees a git_note object
@@ -156,23 +169,28 @@ func (n *Note) Author() *Signature {
 // Id returns the note object's id
 func (n *Note) Id() *Oid {
 	ptr := C.git_note_id(n.ptr)
+	runtime.KeepAlive(n)
 	return newOidFromC(ptr)
 }
 
 // Committer returns the signature of the note committer
 func (n *Note) Committer() *Signature {
 	ptr := C.git_note_committer(n.ptr)
+	runtime.KeepAlive(n)
 	return newSignatureFromC(ptr)
 }
 
 // Message returns the note message
 func (n *Note) Message() string {
-	return C.GoString(C.git_note_message(n.ptr))
+	ret := C.GoString(C.git_note_message(n.ptr))
+	runtime.KeepAlive(n)
+	return ret
 }
 
 // NoteIterator
 type NoteIterator struct {
 	ptr *C.git_note_iterator
+	r   *Repository
 }
 
 // NewNoteIterator creates a new iterator for notes
@@ -190,11 +208,13 @@ func (repo *Repository) NewNoteIterator(ref string) (*NoteIterator, error) {
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	if ret := C.git_note_iterator_new(&ptr, repo.ptr, cref); ret < 0 {
+	ret := C.git_note_iterator_new(&ptr, repo.ptr, cref)
+	runtime.KeepAlive(repo)
+	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
 
-	iter := &NoteIterator{ptr: ptr}
+	iter := &NoteIterator{ptr: ptr, r: repo}
 	runtime.SetFinalizer(iter, (*NoteIterator).Free)
 	return iter, nil
 }
@@ -213,7 +233,11 @@ func (it *NoteIterator) Next() (noteId, annotatedId *Oid, err error) {
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	if ret := C.git_note_next(noteId.toC(), annotatedId.toC(), it.ptr); ret < 0 {
+	ret := C.git_note_next(noteId.toC(), annotatedId.toC(), it.ptr)
+	runtime.KeepAlive(noteId)
+	runtime.KeepAlive(annotatedId)
+	runtime.KeepAlive(it)
+	if ret < 0 {
 		err = MakeGitError(ret)
 	}
 	return
diff --git a/object.go b/object.go
index b365a3f..f4f1b3e 100644
--- a/object.go
+++ b/object.go
@@ -46,7 +46,9 @@ func (t ObjectType) String() string {
 }
 
 func (o *Object) Id() *Oid {
-	return newOidFromC(C.git_object_id(o.ptr))
+	ret := newOidFromC(C.git_object_id(o.ptr))
+	runtime.KeepAlive(o)
+	return ret
 }
 
 func (o *Object) ShortId() (string, error) {
@@ -56,6 +58,7 @@ func (o *Object) ShortId() (string, error) {
 	defer runtime.UnlockOSThread()
 
 	ecode := C.git_object_short_id(&resultBuf, o.ptr)
+	runtime.KeepAlive(o)
 	if ecode < 0 {
 		return "", MakeGitError(ecode)
 	}
@@ -64,15 +67,19 @@ func (o *Object) ShortId() (string, error) {
 }
 
 func (o *Object) Type() ObjectType {
-	return ObjectType(C.git_object_type(o.ptr))
+	ret := ObjectType(C.git_object_type(o.ptr))
+	runtime.KeepAlive(o)
+	return ret
 }
 
 // Owner returns a weak reference to the repository which owns this
 // object. This won't keep the underlying repository alive.
 func (o *Object) Owner() *Repository {
-	return &Repository{
+	ret := &Repository{
 		ptr: C.git_object_owner(o.ptr),
 	}
+	runtime.KeepAlive(o)
+	return ret
 }
 
 func dupObject(obj *Object, kind ObjectType) (*C.git_object, error) {
@@ -85,7 +92,9 @@ func dupObject(obj *Object, kind ObjectType) (*C.git_object, error) {
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	if err := C.git_object_dup(&cobj, obj.ptr); err < 0 {
+	err := C.git_object_dup(&cobj, obj.ptr)
+	runtime.KeepAlive(obj)
+	if err < 0 {
 		return nil, MakeGitError(err)
 	}
 
@@ -203,7 +212,9 @@ func (o *Object) Peel(t ObjectType) (*Object, error) {
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	if err := C.git_object_peel(&cobj, o.ptr, C.git_otype(t)); err < 0 {
+	err := C.git_object_peel(&cobj, o.ptr, C.git_otype(t))
+	runtime.KeepAlive(o)
+	if err < 0 {
 		return nil, MakeGitError(err)
 	}
 
diff --git a/odb.go b/odb.go
index a728cd3..64c5415 100644
--- a/odb.go
+++ b/odb.go
@@ -47,6 +47,7 @@ func (v *Odb) AddBackend(backend *OdbBackend, priority int) (err error) {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_odb_add_backend(v.ptr, backend.ptr, C.int(priority))
+	runtime.KeepAlive(v)
 	if ret < 0 {
 		backend.Free()
 		return MakeGitError(ret)
@@ -57,20 +58,23 @@ func (v *Odb) AddBackend(backend *OdbBackend, priority int) (err error) {
 func (v *Odb) ReadHeader(oid *Oid) (uint64, ObjectType, error) {
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
-	
+
 	var sz C.size_t
-	var cotype C.git_otype 
+	var cotype C.git_otype
 
 	ret := C.git_odb_read_header(&sz, &cotype, v.ptr, oid.toC())
+	runtime.KeepAlive(v)
 	if ret < 0 {
 		return 0, C.GIT_OBJ_BAD, MakeGitError(ret)
 	}
 
 	return uint64(sz), ObjectType(cotype), nil
 }
-	
+
 func (v *Odb) Exists(oid *Oid) bool {
 	ret := C.git_odb_exists(v.ptr, oid.toC())
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(oid)
 	return ret != 0
 }
 
@@ -85,7 +89,7 @@ func (v *Odb) Write(data []byte, otype ObjectType) (oid *Oid, err error) {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_odb_write(oid.toC(), v.ptr, cptr, C.size_t(len(data)), C.git_otype(otype))
-
+	runtime.KeepAlive(v)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
@@ -100,6 +104,8 @@ func (v *Odb) Read(oid *Oid) (obj *OdbObject, err error) {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_odb_read(&obj.ptr, v.ptr, oid.toC())
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(oid)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
@@ -145,6 +151,7 @@ func (v *Odb) ForEach(callback OdbForEachCallback) error {
 	defer pointerHandles.Untrack(handle)
 
 	ret := C._go_git_odb_foreach(v.ptr, handle)
+	runtime.KeepAlive(v)
 	if ret == C.GIT_EUSER {
 		return data.err
 	} else if ret < 0 {
@@ -164,6 +171,7 @@ func (v *Odb) Hash(data []byte, otype ObjectType) (oid *Oid, err error) {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_odb_hash(oid.toC(), ptr, C.size_t(header.Len), C.git_otype(otype))
+	runtime.KeepAlive(data)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
@@ -179,6 +187,8 @@ func (v *Odb) NewReadStream(id *Oid) (*OdbReadStream, error) {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_odb_open_rstream(&stream.ptr, v.ptr, id.toC())
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(id)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
@@ -197,6 +207,7 @@ func (v *Odb) NewWriteStream(size int64, otype ObjectType) (*OdbWriteStream, err
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_odb_open_wstream(&stream.ptr, v.ptr, C.git_off_t(size), C.git_otype(otype))
+	runtime.KeepAlive(v)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
@@ -219,17 +230,25 @@ func (v *OdbObject) Free() {
 }
 
 func (object *OdbObject) Id() (oid *Oid) {
-	return newOidFromC(C.git_odb_object_id(object.ptr))
+	ret := newOidFromC(C.git_odb_object_id(object.ptr))
+	runtime.KeepAlive(object)
+	return ret
 }
 
 func (object *OdbObject) Len() (len uint64) {
-	return uint64(C.git_odb_object_size(object.ptr))
+	ret := uint64(C.git_odb_object_size(object.ptr))
+	runtime.KeepAlive(object)
+	return ret
 }
 
 func (object *OdbObject) Type() ObjectType {
-	return ObjectType(C.git_odb_object_type(object.ptr))
+	ret := ObjectType(C.git_odb_object_type(object.ptr))
+	runtime.KeepAlive(object)
+	return ret
 }
 
+// Data returns a slice pointing to the unmanaged object memory. You must make
+// sure the object is referenced for at least as long as the slice is used.
 func (object *OdbObject) Data() (data []byte) {
 	var c_blob unsafe.Pointer = C.git_odb_object_data(object.ptr)
 	var blob []byte
@@ -258,6 +277,7 @@ func (stream *OdbReadStream) Read(data []byte) (int, error) {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_odb_stream_read(stream.ptr, ptr, size)
+	runtime.KeepAlive(stream)
 	if ret < 0 {
 		return 0, MakeGitError(ret)
 	}
@@ -293,6 +313,7 @@ func (stream *OdbWriteStream) Write(data []byte) (int, error) {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_odb_stream_write(stream.ptr, ptr, size)
+	runtime.KeepAlive(stream)
 	if ret < 0 {
 		return 0, MakeGitError(ret)
 	}
@@ -307,6 +328,7 @@ func (stream *OdbWriteStream) Close() error {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_odb_stream_finalize_write(stream.Id.toC(), stream.ptr)
+	runtime.KeepAlive(stream)
 	if ret < 0 {
 		return MakeGitError(ret)
 	}
diff --git a/packbuilder.go b/packbuilder.go
index 4dc352c..0e04bbf 100644
--- a/packbuilder.go
+++ b/packbuilder.go
@@ -17,20 +17,25 @@ import (
 
 type Packbuilder struct {
 	ptr *C.git_packbuilder
+	r   *Repository
 }
 
 func (repo *Repository) NewPackbuilder() (*Packbuilder, error) {
-	builder := &Packbuilder{}
-
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	ret := C.git_packbuilder_new(&builder.ptr, repo.ptr)
+	var ptr *C.git_packbuilder
+	ret := C.git_packbuilder_new(&ptr, repo.ptr)
 	if ret != 0 {
 		return nil, MakeGitError(ret)
 	}
-	runtime.SetFinalizer(builder, (*Packbuilder).Free)
-	return builder, nil
+	return newPackbuilderFromC(ptr, repo), nil
+}
+
+func newPackbuilderFromC(ptr *C.git_packbuilder, r *Repository) *Packbuilder {
+	pb := &Packbuilder{ptr: ptr, r: r}
+	runtime.SetFinalizer(pb, (*Packbuilder).Free)
+	return pb
 }
 
 func (pb *Packbuilder) Free() {
@@ -46,6 +51,8 @@ func (pb *Packbuilder) Insert(id *Oid, name string) error {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_packbuilder_insert(pb.ptr, id.toC(), cname)
+	runtime.KeepAlive(pb)
+	runtime.KeepAlive(id)
 	if ret != 0 {
 		return MakeGitError(ret)
 	}
@@ -57,6 +64,8 @@ func (pb *Packbuilder) InsertCommit(id *Oid) error {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_packbuilder_insert_commit(pb.ptr, id.toC())
+	runtime.KeepAlive(pb)
+	runtime.KeepAlive(id)
 	if ret != 0 {
 		return MakeGitError(ret)
 	}
@@ -68,6 +77,8 @@ func (pb *Packbuilder) InsertTree(id *Oid) error {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_packbuilder_insert_tree(pb.ptr, id.toC())
+	runtime.KeepAlive(pb)
+	runtime.KeepAlive(id)
 	if ret != 0 {
 		return MakeGitError(ret)
 	}
@@ -75,7 +86,9 @@ func (pb *Packbuilder) InsertTree(id *Oid) error {
 }
 
 func (pb *Packbuilder) ObjectCount() uint32 {
-	return uint32(C.git_packbuilder_object_count(pb.ptr))
+	ret := uint32(C.git_packbuilder_object_count(pb.ptr))
+	runtime.KeepAlive(pb)
+	return ret
 }
 
 func (pb *Packbuilder) WriteToFile(name string, mode os.FileMode) error {
@@ -86,6 +99,7 @@ func (pb *Packbuilder) WriteToFile(name string, mode os.FileMode) error {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_packbuilder_write(pb.ptr, cname, C.uint(mode.Perm()), nil, nil)
+	runtime.KeepAlive(pb)
 	if ret != 0 {
 		return MakeGitError(ret)
 	}
@@ -100,7 +114,9 @@ func (pb *Packbuilder) Write(w io.Writer) error {
 }
 
 func (pb *Packbuilder) Written() uint32 {
-	return uint32(C.git_packbuilder_written(pb.ptr))
+	ret := uint32(C.git_packbuilder_written(pb.ptr))
+	runtime.KeepAlive(pb)
+	return ret
 }
 
 type PackbuilderForeachCallback func([]byte) error
@@ -142,6 +158,7 @@ func (pb *Packbuilder) ForEach(callback PackbuilderForeachCallback) error {
 	defer runtime.UnlockOSThread()
 
 	err := C._go_git_packbuilder_foreach(pb.ptr, handle)
+	runtime.KeepAlive(pb)
 	if err == C.GIT_EUSER {
 		return data.err
 	}
diff --git a/patch.go b/patch.go
index 0d0df7f..75e843c 100644
--- a/patch.go
+++ b/patch.go
@@ -47,6 +47,7 @@ func (patch *Patch) String() (string, error) {
 	var buf C.git_buf
 
 	ecode := C.git_patch_to_buf(&buf, patch.ptr)
+	runtime.KeepAlive(patch)
 	if ecode < 0 {
 		return "", MakeGitError(ecode)
 	}
@@ -83,6 +84,8 @@ func (v *Repository) PatchFromBuffers(oldPath, newPath string, oldBuf, newBuf []
 	defer runtime.UnlockOSThread()
 
 	ecode := C.git_patch_from_buffers(&patchPtr, oldPtr, C.size_t(len(oldBuf)), cOldPath, newPtr, C.size_t(len(newBuf)), cNewPath, copts)
+	runtime.KeepAlive(oldBuf)
+	runtime.KeepAlive(newBuf)
 	if ecode < 0 {
 		return nil, MakeGitError(ecode)
 	}
diff --git a/rebase.go b/rebase.go
index 8553e25..390b924 100644
--- a/rebase.go
+++ b/rebase.go
@@ -100,6 +100,7 @@ func mapEmptyStringToNull(ref string) *C.char {
 // Rebase is the struct representing a Rebase object.
 type Rebase struct {
 	ptr *C.git_rebase
+	r   *Repository
 }
 
 // InitRebase initializes a rebase operation to rebase the changes in branch relative to upstream onto another branch.
@@ -121,6 +122,9 @@ func (r *Repository) InitRebase(branch *AnnotatedCommit, upstream *AnnotatedComm
 
 	var ptr *C.git_rebase
 	err := C.git_rebase_init(&ptr, r.ptr, branch.ptr, upstream.ptr, onto.ptr, opts.toC())
+	runtime.KeepAlive(branch)
+	runtime.KeepAlive(upstream)
+	runtime.KeepAlive(onto)
 	if err < 0 {
 		return nil, MakeGitError(err)
 	}
@@ -135,6 +139,7 @@ func (r *Repository) OpenRebase(opts *RebaseOptions) (*Rebase, error) {
 
 	var ptr *C.git_rebase
 	err := C.git_rebase_open(&ptr, r.ptr, opts.toC())
+	runtime.KeepAlive(r)
 	if err < 0 {
 		return nil, MakeGitError(err)
 	}
@@ -145,7 +150,7 @@ func (r *Repository) OpenRebase(opts *RebaseOptions) (*Rebase, error) {
 // OperationAt gets the rebase operation specified by the given index.
 func (rebase *Rebase) OperationAt(index uint) *RebaseOperation {
 	operation := C.git_rebase_operation_byindex(rebase.ptr, C.size_t(index))
-	
+
 	return newRebaseOperationFromC(operation)
 }
 
@@ -165,7 +170,9 @@ func (rebase *Rebase) CurrentOperationIndex() (uint, error) {
 
 // OperationCount gets the count of rebase operations that are to be applied.
 func (rebase *Rebase) OperationCount() uint {
-	return uint(C.git_rebase_operation_entrycount(rebase.ptr))
+	ret := uint(C.git_rebase_operation_entrycount(rebase.ptr))
+	runtime.KeepAlive(rebase)
+	return ret
 }
 
 // Next performs the next rebase operation and returns the information about it.
@@ -178,6 +185,7 @@ func (rebase *Rebase) Next() (*RebaseOperation, error) {
 
 	var ptr *C.git_rebase_operation
 	err := C.git_rebase_next(&ptr, rebase.ptr)
+	runtime.KeepAlive(rebase)
 	if err < 0 {
 		return nil, MakeGitError(err)
 	}
@@ -207,6 +215,8 @@ func (rebase *Rebase) Commit(ID *Oid, author, committer *Signature, message stri
 	defer C.free(unsafe.Pointer(cmsg))
 
 	cerr := C.git_rebase_commit(ID.toC(), rebase.ptr, authorSig, committerSig, nil, cmsg)
+	runtime.KeepAlive(ID)
+	runtime.KeepAlive(rebase)
 	if cerr < 0 {
 		return MakeGitError(cerr)
 	}
@@ -220,6 +230,7 @@ func (rebase *Rebase) Finish() error {
 	defer runtime.UnlockOSThread()
 
 	err := C.git_rebase_finish(rebase.ptr, nil)
+	runtime.KeepAlive(rebase)
 	if err < 0 {
 		return MakeGitError(err)
 	}
@@ -233,6 +244,7 @@ func (rebase *Rebase) Abort() error {
 	defer runtime.UnlockOSThread()
 
 	err := C.git_rebase_abort(rebase.ptr)
+	runtime.KeepAlive(rebase)
 	if err < 0 {
 		return MakeGitError(err)
 	}
diff --git a/refdb.go b/refdb.go
index 4e3ebf9..578f43c 100644
--- a/refdb.go
+++ b/refdb.go
@@ -14,6 +14,7 @@ import (
 
 type Refdb struct {
 	ptr *C.git_refdb
+	r   *Repository
 }
 
 type RefdbBackend struct {
@@ -21,16 +22,17 @@ type RefdbBackend struct {
 }
 
 func (v *Repository) NewRefdb() (refdb *Refdb, err error) {
-	refdb = new(Refdb)
+	var ptr *C.git_refdb
 
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	ret := C.git_refdb_new(&refdb.ptr, v.ptr)
+	ret := C.git_refdb_new(&ptr, v.ptr)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
 
+	refdb = &Refdb{ptr: ptr, r: v}
 	runtime.SetFinalizer(refdb, (*Refdb).Free)
 	return refdb, nil
 }
@@ -45,6 +47,8 @@ func (v *Refdb) SetBackend(backend *RefdbBackend) (err error) {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_refdb_set_backend(v.ptr, backend.ptr)
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(backend)
 	if ret < 0 {
 		backend.Free()
 		return MakeGitError(ret)
@@ -53,5 +57,6 @@ func (v *Refdb) SetBackend(backend *RefdbBackend) (err error) {
 }
 
 func (v *RefdbBackend) Free() {
+	runtime.SetFinalizer(v, nil)
 	C._go_git_refdb_backend_free(v.ptr)
 }
diff --git a/reference.go b/reference.go
index 463f2fc..e10c9b2 100644
--- a/reference.go
+++ b/reference.go
@@ -34,6 +34,7 @@ func (c *ReferenceCollection) Lookup(name string) (*Reference, error) {
 	defer runtime.UnlockOSThread()
 
 	ecode := C.git_reference_lookup(&ptr, c.repo.ptr, cname)
+	runtime.KeepAlive(c)
 	if ecode < 0 {
 		return nil, MakeGitError(ecode)
 	}
@@ -59,6 +60,8 @@ func (c *ReferenceCollection) Create(name string, id *Oid, force bool, msg strin
 	defer runtime.UnlockOSThread()
 
 	ecode := C.git_reference_create(&ptr, c.repo.ptr, cname, id.toC(), cbool(force), cmsg)
+	runtime.KeepAlive(c)
+	runtime.KeepAlive(id)
 	if ecode < 0 {
 		return nil, MakeGitError(ecode)
 	}
@@ -87,6 +90,7 @@ func (c *ReferenceCollection) CreateSymbolic(name, target string, force bool, ms
 	defer runtime.UnlockOSThread()
 
 	ecode := C.git_reference_symbolic_create(&ptr, c.repo.ptr, cname, ctarget, cbool(force), cmsg)
+	runtime.KeepAlive(c)
 	if ecode < 0 {
 		return nil, MakeGitError(ecode)
 	}
@@ -104,6 +108,7 @@ func (c *ReferenceCollection) EnsureLog(name string) error {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_reference_ensure_log(c.repo.ptr, cname)
+	runtime.KeepAlive(c)
 	if ret < 0 {
 		return MakeGitError(ret)
 	}
@@ -121,6 +126,7 @@ func (c *ReferenceCollection) HasLog(name string) (bool, error) {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_reference_has_log(c.repo.ptr, cname)
+	runtime.KeepAlive(c)
 	if ret < 0 {
 		return false, MakeGitError(ret)
 	}
@@ -138,6 +144,7 @@ func (c *ReferenceCollection) Dwim(name string) (*Reference, error) {
 
 	var ptr *C.git_reference
 	ret := C.git_reference_dwim(&ptr, c.repo.ptr, cname)
+	runtime.KeepAlive(c)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
@@ -169,6 +176,7 @@ func (v *Reference) SetSymbolicTarget(target string, msg string) (*Reference, er
 	}
 
 	ret := C.git_reference_symbolic_set_target(&ptr, v.ptr, ctarget, cmsg)
+	runtime.KeepAlive(v)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
@@ -191,6 +199,7 @@ func (v *Reference) SetTarget(target *Oid, msg string) (*Reference, error) {
 	}
 
 	ret := C.git_reference_set_target(&ptr, v.ptr, target.toC(), cmsg)
+	runtime.KeepAlive(v)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
@@ -205,6 +214,7 @@ func (v *Reference) Resolve() (*Reference, error) {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_reference_resolve(&ptr, v.ptr)
+	runtime.KeepAlive(v)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
@@ -229,7 +239,7 @@ func (v *Reference) Rename(name string, force bool, msg string) (*Reference, err
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_reference_rename(&ptr, v.ptr, cname, cbool(force), cmsg)
-
+	runtime.KeepAlive(v)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
@@ -238,16 +248,21 @@ func (v *Reference) Rename(name string, force bool, msg string) (*Reference, err
 }
 
 func (v *Reference) Target() *Oid {
-	return newOidFromC(C.git_reference_target(v.ptr))
+	ret := newOidFromC(C.git_reference_target(v.ptr))
+	runtime.KeepAlive(v)
+	return ret
 }
 
 func (v *Reference) SymbolicTarget() string {
+	var ret string
 	cstr := C.git_reference_symbolic_target(v.ptr)
-	if cstr == nil {
-		return ""
+
+	if cstr != nil {
+		return C.GoString(cstr)
 	}
 
-	return C.GoString(cstr)
+	runtime.KeepAlive(v)
+	return ret
 }
 
 func (v *Reference) Delete() error {
@@ -255,7 +270,7 @@ func (v *Reference) Delete() error {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_reference_delete(v.ptr)
-
+	runtime.KeepAlive(v)
 	if ret < 0 {
 		return MakeGitError(ret)
 	}
@@ -269,7 +284,9 @@ func (v *Reference) Peel(t ObjectType) (*Object, error) {
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	if err := C.git_reference_peel(&cobj, v.ptr, C.git_otype(t)); err < 0 {
+	err := C.git_reference_peel(&cobj, v.ptr, C.git_otype(t))
+	runtime.KeepAlive(v)
+	if err < 0 {
 		return nil, MakeGitError(err)
 	}
 
@@ -287,37 +304,54 @@ func (v *Reference) Owner() *Repository {
 // Cmp compares both references, retursn 0 on equality, otherwise a
 // stable sorting.
 func (v *Reference) Cmp(ref2 *Reference) int {
-	return int(C.git_reference_cmp(v.ptr, ref2.ptr))
+	ret := int(C.git_reference_cmp(v.ptr, ref2.ptr))
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(ref2)
+	return ret
 }
 
-// Shorthand returns a "human-readable" short reference name
+// Shorthand ret :=s a "human-readable" short reference name
 func (v *Reference) Shorthand() string {
-	return C.GoString(C.git_reference_shorthand(v.ptr))
+	ret := C.GoString(C.git_reference_shorthand(v.ptr))
+	runtime.KeepAlive(v)
+	return ret
 }
 
 func (v *Reference) Name() string {
-	return C.GoString(C.git_reference_name(v.ptr))
+	ret := C.GoString(C.git_reference_name(v.ptr))
+	runtime.KeepAlive(v)
+	return ret
 }
 
 func (v *Reference) Type() ReferenceType {
-	return ReferenceType(C.git_reference_type(v.ptr))
+	ret := ReferenceType(C.git_reference_type(v.ptr))
+	runtime.KeepAlive(v)
+	return ret
 }
 
 func (v *Reference) IsBranch() bool {
-	return C.git_reference_is_branch(v.ptr) == 1
+	ret := C.git_reference_is_branch(v.ptr) == 1
+	runtime.KeepAlive(v)
+	return ret
 }
 
 func (v *Reference) IsRemote() bool {
-	return C.git_reference_is_remote(v.ptr) == 1
+	ret := C.git_reference_is_remote(v.ptr) == 1
+	runtime.KeepAlive(v)
+	return ret
 }
 
 func (v *Reference) IsTag() bool {
-	return C.git_reference_is_tag(v.ptr) == 1
+	ret := C.git_reference_is_tag(v.ptr) == 1
+	runtime.KeepAlive(v)
+	return ret
 }
 
 // IsNote checks if the reference is a note.
 func (v *Reference) IsNote() bool {
-	return C.git_reference_is_note(v.ptr) == 1
+	ret := C.git_reference_is_note(v.ptr) == 1
+	runtime.KeepAlive(v)
+	return ret
 }
 
 func (v *Reference) Free() {
@@ -346,9 +380,7 @@ func (repo *Repository) NewReferenceIterator() (*ReferenceIterator, error) {
 		return nil, MakeGitError(ret)
 	}
 
-	iter := &ReferenceIterator{ptr: ptr, repo: repo}
-	runtime.SetFinalizer(iter, (*ReferenceIterator).Free)
-	return iter, nil
+	return newReferenceIteratorFromC(ptr, repo), nil
 }
 
 // NewReferenceIterator creates a new branch iterator over reference names
@@ -363,8 +395,7 @@ func (repo *Repository) NewReferenceNameIterator() (*ReferenceNameIterator, erro
 		return nil, MakeGitError(ret)
 	}
 
-	iter := &ReferenceIterator{ptr: ptr, repo: repo}
-	runtime.SetFinalizer(iter, (*ReferenceIterator).Free)
+	iter := newReferenceIteratorFromC(ptr, repo)
 	return iter.Names(), nil
 }
 
@@ -384,9 +415,7 @@ func (repo *Repository) NewReferenceIteratorGlob(glob string) (*ReferenceIterato
 		return nil, MakeGitError(ret)
 	}
 
-	iter := &ReferenceIterator{ptr: ptr}
-	runtime.SetFinalizer(iter, (*ReferenceIterator).Free)
-	return iter, nil
+	return newReferenceIteratorFromC(ptr, repo), nil
 }
 
 func (i *ReferenceIterator) Names() *ReferenceNameIterator {
@@ -425,6 +454,13 @@ func (v *ReferenceIterator) Next() (*Reference, error) {
 	return newReferenceFromC(ptr, v.repo), nil
 }
 
+func newReferenceIteratorFromC(ptr *C.git_reference_iterator, r *Repository) *ReferenceIterator {
+	return &ReferenceIterator{
+		ptr:  ptr,
+		repo: r,
+	}
+}
+
 // Free the reference iterator
 func (v *ReferenceIterator) Free() {
 	runtime.SetFinalizer(v, nil)
diff --git a/repository.go b/repository.go
index 6b07e87..abf8b71 100644
--- a/repository.go
+++ b/repository.go
@@ -120,6 +120,7 @@ func NewRepositoryWrapOdb(odb *Odb) (repo *Repository, err error) {
 
 	var ptr *C.git_repository
 	ret := C.git_repository_wrap_odb(&ptr, odb.ptr)
+	runtime.KeepAlive(odb)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
diff --git a/signature.go b/signature.go
index 0518387..16964d2 100644
--- a/signature.go
+++ b/signature.go
@@ -63,6 +63,7 @@ func (repo *Repository) DefaultSignature() (*Signature, error) {
 	defer runtime.UnlockOSThread()
 
 	cErr := C.git_signature_default(&out, repo.ptr)
+	runtime.KeepAlive(repo)
 	if cErr < 0 {
 		return nil, MakeGitError(cErr)
 	}
diff --git a/stash.go b/stash.go
index 809732e..8743da8 100644
--- a/stash.go
+++ b/stash.go
@@ -63,7 +63,7 @@ func (c *StashCollection) Save(
 	ret := C.git_stash_save(
 		oid.toC(), c.repo.ptr,
 		stasherC, messageC, C.uint32_t(flags))
-
+	runtime.KeepAlive(c)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
@@ -228,6 +228,7 @@ func (c *StashCollection) Apply(index int, opts StashApplyOptions) error {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_stash_apply(c.repo.ptr, C.size_t(index), optsC)
+	runtime.KeepAlive(c)
 	if ret == C.GIT_EUSER {
 		return progressData.Error
 	}
@@ -282,6 +283,7 @@ func (c *StashCollection) Foreach(callback StashCallback) error {
 	defer runtime.UnlockOSThread()
 
 	ret := C._go_git_stash_foreach(c.repo.ptr, handle)
+	runtime.KeepAlive(c)
 	if ret == C.GIT_EUSER {
 		return data.Error
 	}
@@ -303,6 +305,7 @@ func (c *StashCollection) Drop(index int) error {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_stash_drop(c.repo.ptr, C.size_t(index))
+	runtime.KeepAlive(c)
 	if ret < 0 {
 		return MakeGitError(ret)
 	}
@@ -328,6 +331,7 @@ func (c *StashCollection) Pop(index int, opts StashApplyOptions) error {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_stash_pop(c.repo.ptr, C.size_t(index), optsC)
+	runtime.KeepAlive(c)
 	if ret == C.GIT_EUSER {
 		return progressData.Error
 	}
diff --git a/status.go b/status.go
index e68e6e9..e37a96d 100644
--- a/status.go
+++ b/status.go
@@ -55,15 +55,17 @@ func statusEntryFromC(statusEntry *C.git_status_entry) StatusEntry {
 
 type StatusList struct {
 	ptr *C.git_status_list
+	r   *Repository
 }
 
-func newStatusListFromC(ptr *C.git_status_list) *StatusList {
+func newStatusListFromC(ptr *C.git_status_list, r *Repository) *StatusList {
 	if ptr == nil {
 		return nil
 	}
 
 	statusList := &StatusList{
 		ptr: ptr,
+		r:   r,
 	}
 
 	runtime.SetFinalizer(statusList, (*StatusList).Free)
@@ -84,14 +86,20 @@ func (statusList *StatusList) ByIndex(index int) (StatusEntry, error) {
 		return StatusEntry{}, ErrInvalid
 	}
 	ptr := C.git_status_byindex(statusList.ptr, C.size_t(index))
-	return statusEntryFromC(ptr), nil
+	entry := statusEntryFromC(ptr)
+	runtime.KeepAlive(statusList)
+
+	return entry, nil
 }
 
 func (statusList *StatusList) EntryCount() (int, error) {
 	if statusList.ptr == nil {
 		return -1, ErrInvalid
 	}
-	return int(C.git_status_list_entrycount(statusList.ptr)), nil
+	ret := int(C.git_status_list_entrycount(statusList.ptr))
+	runtime.KeepAlive(statusList)
+
+	return ret, nil
 }
 
 type StatusOpt int
@@ -161,7 +169,7 @@ func (v *Repository) StatusList(opts *StatusOptions) (*StatusList, error) {
 		return nil, MakeGitError(ret)
 	}
 
-	return newStatusListFromC(ptr), nil
+	return newStatusListFromC(ptr, v), nil
 }
 
 func (v *Repository) StatusFile(path string) (Status, error) {
@@ -173,6 +181,7 @@ func (v *Repository) StatusFile(path string) (Status, error) {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_status_file(&statusFlags, v.ptr, cPath)
+	runtime.KeepAlive(v)
 	if ret < 0 {
 		return 0, MakeGitError(ret)
 	}
diff --git a/submodule.go b/submodule.go
index 4a32ce4..406ed08 100644
--- a/submodule.go
+++ b/submodule.go
@@ -21,6 +21,18 @@ type SubmoduleUpdateOptions struct {
 // Submodule
 type Submodule struct {
 	ptr *C.git_submodule
+	r   *Repository
+}
+
+func newSubmoduleFromC(ptr *C.git_submodule, r *Repository) *Submodule {
+	s := &Submodule{ptr: ptr, r: r}
+	runtime.SetFinalizer(s, (*Submodule).Free)
+	return s
+}
+
+func (sub *Submodule) Free() {
+	runtime.SetFinalizer(sub, nil)
+	C.git_submodule_free(sub.ptr)
 }
 
 type SubmoduleUpdate int
@@ -82,24 +94,24 @@ func (c *SubmoduleCollection) Lookup(name string) (*Submodule, error) {
 	cname := C.CString(name)
 	defer C.free(unsafe.Pointer(cname))
 
-	sub := new(Submodule)
+	var ptr *C.git_submodule
 
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	ret := C.git_submodule_lookup(&sub.ptr, c.repo.ptr, cname)
+	ret := C.git_submodule_lookup(&ptr, c.repo.ptr, cname)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
 
-	return sub, nil
+	return newSubmoduleFromC(ptr, c.repo), nil
 }
 
 type SubmoduleCbk func(sub *Submodule, name string) int
 
 //export SubmoduleVisitor
 func SubmoduleVisitor(csub unsafe.Pointer, name *C.char, handle unsafe.Pointer) C.int {
-	sub := &Submodule{(*C.git_submodule)(csub)}
+	sub := &Submodule{(*C.git_submodule)(csub), nil}
 
 	if callback, ok := pointerHandles.Get(handle).(SubmoduleCbk); ok {
 		return (C.int)(callback(sub, C.GoString(name)))
@@ -116,6 +128,7 @@ func (c *SubmoduleCollection) Foreach(cbk SubmoduleCbk) error {
 	defer pointerHandles.Untrack(handle)
 
 	ret := C._go_git_visit_submodule(c.repo.ptr, handle)
+	runtime.KeepAlive(c)
 	if ret < 0 {
 		return MakeGitError(ret)
 	}
@@ -128,16 +141,15 @@ func (c *SubmoduleCollection) Add(url, path string, use_git_link bool) (*Submodu
 	cpath := C.CString(path)
 	defer C.free(unsafe.Pointer(cpath))
 
-	sub := new(Submodule)
-
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	ret := C.git_submodule_add_setup(&sub.ptr, c.repo.ptr, curl, cpath, cbool(use_git_link))
+	var ptr *C.git_submodule
+	ret := C.git_submodule_add_setup(&ptr, c.repo.ptr, curl, cpath, cbool(use_git_link))
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
-	return sub, nil
+	return newSubmoduleFromC(ptr, c.repo), nil
 }
 
 func (sub *Submodule) FinalizeAdd() error {
@@ -145,6 +157,7 @@ func (sub *Submodule) FinalizeAdd() error {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_submodule_add_finalize(sub.ptr)
+	runtime.KeepAlive(sub)
 	if ret < 0 {
 		return MakeGitError(ret)
 	}
@@ -156,6 +169,7 @@ func (sub *Submodule) AddToIndex(write_index bool) error {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_submodule_add_to_index(sub.ptr, cbool(write_index))
+	runtime.KeepAlive(sub)
 	if ret < 0 {
 		return MakeGitError(ret)
 	}
@@ -163,18 +177,21 @@ func (sub *Submodule) AddToIndex(write_index bool) error {
 }
 
 func (sub *Submodule) Name() string {
-	n := C.git_submodule_name(sub.ptr)
-	return C.GoString(n)
+	n := C.GoString(C.git_submodule_name(sub.ptr))
+	runtime.KeepAlive(sub)
+	return n
 }
 
 func (sub *Submodule) Path() string {
-	n := C.git_submodule_path(sub.ptr)
-	return C.GoString(n)
+	n := C.GoString(C.git_submodule_path(sub.ptr))
+	runtime.KeepAlive(sub)
+	return n
 }
 
 func (sub *Submodule) Url() string {
-	n := C.git_submodule_url(sub.ptr)
-	return C.GoString(n)
+	n := C.GoString(C.git_submodule_url(sub.ptr))
+	runtime.KeepAlive(sub)
+	return n
 }
 
 func (c *SubmoduleCollection) SetUrl(submodule, url string) error {
@@ -187,6 +204,7 @@ func (c *SubmoduleCollection) SetUrl(submodule, url string) error {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_submodule_set_url(c.repo.ptr, csubmodule, curl)
+	runtime.KeepAlive(c)
 	if ret < 0 {
 		return MakeGitError(ret)
 	}
@@ -194,31 +212,38 @@ func (c *SubmoduleCollection) SetUrl(submodule, url string) error {
 }
 
 func (sub *Submodule) IndexId() *Oid {
+	var id *Oid
 	idx := C.git_submodule_index_id(sub.ptr)
-	if idx == nil {
-		return nil
+	if idx != nil {
+		id = newOidFromC(idx)
 	}
-	return newOidFromC(idx)
+	runtime.KeepAlive(sub)
+	return id
 }
 
 func (sub *Submodule) HeadId() *Oid {
+	var id *Oid
 	idx := C.git_submodule_head_id(sub.ptr)
-	if idx == nil {
-		return nil
+	if idx != nil {
+		id = newOidFromC(idx)
 	}
-	return newOidFromC(idx)
+	runtime.KeepAlive(sub)
+	return id
 }
 
 func (sub *Submodule) WdId() *Oid {
+	var id *Oid
 	idx := C.git_submodule_wd_id(sub.ptr)
-	if idx == nil {
-		return nil
+	if idx != nil {
+		id = newOidFromC(idx)
 	}
-	return newOidFromC(idx)
+	runtime.KeepAlive(sub)
+	return id
 }
 
 func (sub *Submodule) Ignore() SubmoduleIgnore {
 	o := C.git_submodule_ignore(sub.ptr)
+	runtime.KeepAlive(sub)
 	return SubmoduleIgnore(o)
 }
 
@@ -230,6 +255,7 @@ func (c *SubmoduleCollection) SetIgnore(submodule string, ignore SubmoduleIgnore
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_submodule_set_ignore(c.repo.ptr, csubmodule, C.git_submodule_ignore_t(ignore))
+	runtime.KeepAlive(c)
 	if ret < 0 {
 		return MakeGitError(ret)
 	}
@@ -239,6 +265,7 @@ func (c *SubmoduleCollection) SetIgnore(submodule string, ignore SubmoduleIgnore
 
 func (sub *Submodule) UpdateStrategy() SubmoduleUpdate {
 	o := C.git_submodule_update_strategy(sub.ptr)
+	runtime.KeepAlive(sub)
 	return SubmoduleUpdate(o)
 }
 
@@ -250,6 +277,7 @@ func (c *SubmoduleCollection) SetUpdate(submodule string, update SubmoduleUpdate
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_submodule_set_update(c.repo.ptr, csubmodule, C.git_submodule_update_t(update))
+	runtime.KeepAlive(c)
 	if ret < 0 {
 		return MakeGitError(ret)
 	}
@@ -269,6 +297,7 @@ func (c *SubmoduleCollection) SetFetchRecurseSubmodules(submodule string, recurs
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_submodule_set_fetch_recurse_submodules(c.repo.ptr, csubmodule, C.git_submodule_recurse_t(recurse))
+	runtime.KeepAlive(c)
 	if ret < 0 {
 		return MakeGitError(C.int(ret))
 	}
@@ -280,6 +309,7 @@ func (sub *Submodule) Init(overwrite bool) error {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_submodule_init(sub.ptr, cbool(overwrite))
+	runtime.KeepAlive(sub)
 	if ret < 0 {
 		return MakeGitError(ret)
 	}
@@ -291,6 +321,7 @@ func (sub *Submodule) Sync() error {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_submodule_sync(sub.ptr)
+	runtime.KeepAlive(sub)
 	if ret < 0 {
 		return MakeGitError(ret)
 	}
@@ -303,6 +334,7 @@ func (sub *Submodule) Open() (*Repository, error) {
 
 	var ptr *C.git_repository
 	ret := C.git_submodule_open(&ptr, sub.ptr)
+	runtime.KeepAlive(sub)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
@@ -320,6 +352,7 @@ func (sub *Submodule) Update(init bool, opts *SubmoduleUpdateOptions) error {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_submodule_update(sub.ptr, cbool(init), &copts)
+	runtime.KeepAlive(sub)
 	if ret < 0 {
 		return MakeGitError(ret)
 	}
diff --git a/tag.go b/tag.go
index 81d7258..a58b090 100644
--- a/tag.go
+++ b/tag.go
@@ -18,22 +18,28 @@ type Tag struct {
 }
 
 func (t Tag) Message() string {
-	return C.GoString(C.git_tag_message(t.cast_ptr))
+	ret := C.GoString(C.git_tag_message(t.cast_ptr))
+	runtime.KeepAlive(t)
+	return ret
 }
 
 func (t Tag) Name() string {
-	return C.GoString(C.git_tag_name(t.cast_ptr))
+	ret := C.GoString(C.git_tag_name(t.cast_ptr))
+	runtime.KeepAlive(t)
+	return ret
 }
 
 func (t Tag) Tagger() *Signature {
 	cast_ptr := C.git_tag_tagger(t.cast_ptr)
-	return newSignatureFromC(cast_ptr)
+	ret := newSignatureFromC(cast_ptr)
+	runtime.KeepAlive(t)
+	return ret
 }
 
 func (t Tag) Target() *Object {
 	var ptr *C.git_object
 	ret := C.git_tag_target(&ptr, t.cast_ptr)
-
+	runtime.KeepAlive(t)
 	if ret != 0 {
 		return nil
 	}
@@ -42,11 +48,15 @@ func (t Tag) Target() *Object {
 }
 
 func (t Tag) TargetId() *Oid {
-	return newOidFromC(C.git_tag_target_id(t.cast_ptr))
+	ret := newOidFromC(C.git_tag_target_id(t.cast_ptr))
+	runtime.KeepAlive(t)
+	return ret
 }
 
 func (t Tag) TargetType() ObjectType {
-	return ObjectType(C.git_tag_target_type(t.cast_ptr))
+	ret := ObjectType(C.git_tag_target_type(t.cast_ptr))
+	runtime.KeepAlive(t)
+	return ret
 }
 
 type TagsCollection struct {
@@ -76,6 +86,7 @@ func (c *TagsCollection) Create(
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_tag_create(oid.toC(), c.repo.ptr, cname, ctarget, taggerSig, cmessage, 0)
+	runtime.KeepAlive(c)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
@@ -91,6 +102,7 @@ func (c *TagsCollection) Remove(name string) error {
 	defer C.free(unsafe.Pointer(cname))
 
 	ret := C.git_tag_delete(c.repo.ptr, cname)
+	runtime.KeepAlive(c)
 	if ret < 0 {
 		return MakeGitError(ret)
 	}
@@ -123,6 +135,7 @@ func (c *TagsCollection) CreateLightweight(name string, commit *Commit, force bo
 	defer runtime.UnlockOSThread()
 
 	err := C.git_tag_create_lightweight(oid.toC(), c.repo.ptr, cname, ctarget, cbool(force))
+	runtime.KeepAlive(c)
 	if err < 0 {
 		return nil, MakeGitError(err)
 	}
@@ -139,6 +152,7 @@ func (c *TagsCollection) List() ([]string, error) {
 	defer runtime.UnlockOSThread()
 
 	ecode := C.git_tag_list(&strC, c.repo.ptr)
+	runtime.KeepAlive(c)
 	if ecode < 0 {
 		return nil, MakeGitError(ecode)
 	}
@@ -162,6 +176,7 @@ func (c *TagsCollection) ListWithMatch(pattern string) ([]string, error) {
 	defer runtime.UnlockOSThread()
 
 	ecode := C.git_tag_list_match(&strC, patternC, c.repo.ptr)
+	runtime.KeepAlive(c)
 	if ecode < 0 {
 		return nil, MakeGitError(ecode)
 	}
@@ -215,6 +230,7 @@ func (c *TagsCollection) Foreach(callback TagForeachCallback) error {
 	defer runtime.UnlockOSThread()
 
 	err := C._go_git_tag_foreach(c.repo.ptr, handle)
+	runtime.KeepAlive(c)
 	if err == C.GIT_EUSER {
 		return data.err
 	}
diff --git a/tree.go b/tree.go
index 27dd63d..f5cbd78 100644
--- a/tree.go
+++ b/tree.go
@@ -48,6 +48,7 @@ func (t Tree) EntryByName(filename string) *TreeEntry {
 	defer C.free(unsafe.Pointer(cname))
 
 	entry := C.git_tree_entry_byname(t.cast_ptr, cname)
+	runtime.KeepAlive(t)
 	if entry == nil {
 		return nil
 	}
@@ -66,6 +67,8 @@ func (t Tree) EntryById(id *Oid) *TreeEntry {
 	defer runtime.UnlockOSThread()
 
 	entry := C.git_tree_entry_byid(t.cast_ptr, id.toC())
+	runtime.KeepAlive(t)
+	runtime.KeepAlive(id)
 	if entry == nil {
 		return nil
 	}
@@ -84,6 +87,7 @@ func (t Tree) EntryByPath(path string) (*TreeEntry, error) {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_tree_entry_bypath(&entry, t.cast_ptr, cpath)
+	runtime.KeepAlive(t)
 	if ret < 0 {
 		return nil, MakeGitError(ret)
 	}
@@ -94,6 +98,7 @@ func (t Tree) EntryByPath(path string) (*TreeEntry, error) {
 
 func (t Tree) EntryByIndex(index uint64) *TreeEntry {
 	entry := C.git_tree_entry_byindex(t.cast_ptr, C.size_t(index))
+	runtime.KeepAlive(t)
 	if entry == nil {
 		return nil
 	}
@@ -103,6 +108,7 @@ func (t Tree) EntryByIndex(index uint64) *TreeEntry {
 
 func (t Tree) EntryCount() uint64 {
 	num := C.git_tree_entrycount(t.cast_ptr)
+	runtime.KeepAlive(t)
 	return uint64(num)
 }
 
@@ -132,7 +138,7 @@ func (t Tree) Walk(callback TreeWalkCallback) error {
 		C.GIT_TREEWALK_PRE,
 		ptr,
 	)
-
+	runtime.KeepAlive(t)
 	if err < 0 {
 		return MakeGitError(err)
 	}
@@ -158,6 +164,8 @@ func (v *TreeBuilder) Insert(filename string, id *Oid, filemode Filemode) error
 	defer runtime.UnlockOSThread()
 
 	err := C.git_treebuilder_insert(nil, v.ptr, cfilename, id.toC(), C.git_filemode_t(filemode))
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(id)
 	if err < 0 {
 		return MakeGitError(err)
 	}
@@ -173,6 +181,7 @@ func (v *TreeBuilder) Remove(filename string) error {
 	defer runtime.UnlockOSThread()
 
 	err := C.git_treebuilder_remove(v.ptr, cfilename)
+	runtime.KeepAlive(v)
 	if err < 0 {
 		return MakeGitError(err)
 	}
@@ -187,7 +196,7 @@ func (v *TreeBuilder) Write() (*Oid, error) {
 	defer runtime.UnlockOSThread()
 
 	err := C.git_treebuilder_write(oid.toC(), v.ptr)
-
+	runtime.KeepAlive(v)
 	if err < 0 {
 		return nil, MakeGitError(err)
 	}
diff --git a/walk.go b/walk.go
index ab1de61..287edb6 100644
--- a/walk.go
+++ b/walk.go
@@ -34,6 +34,7 @@ func revWalkFromC(repo *Repository, c *C.git_revwalk) *RevWalk {
 
 func (v *RevWalk) Reset() {
 	C.git_revwalk_reset(v.ptr)
+	runtime.KeepAlive(v)
 }
 
 func (v *RevWalk) Push(id *Oid) error {
@@ -41,6 +42,8 @@ func (v *RevWalk) Push(id *Oid) error {
 	defer runtime.UnlockOSThread()
 
 	ecode := C.git_revwalk_push(v.ptr, id.toC())
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(id)
 	if ecode < 0 {
 		return MakeGitError(ecode)
 	}
@@ -55,6 +58,7 @@ func (v *RevWalk) PushGlob(glob string) error {
 	defer C.free(unsafe.Pointer(cstr))
 
 	ecode := C.git_revwalk_push_glob(v.ptr, cstr)
+	runtime.KeepAlive(v)
 	if ecode < 0 {
 		return MakeGitError(ecode)
 	}
@@ -69,6 +73,7 @@ func (v *RevWalk) PushRange(r string) error {
 	defer C.free(unsafe.Pointer(cstr))
 
 	ecode := C.git_revwalk_push_range(v.ptr, cstr)
+	runtime.KeepAlive(v)
 	if ecode < 0 {
 		return MakeGitError(ecode)
 	}
@@ -83,6 +88,7 @@ func (v *RevWalk) PushRef(r string) error {
 	defer C.free(unsafe.Pointer(cstr))
 
 	ecode := C.git_revwalk_push_ref(v.ptr, cstr)
+	runtime.KeepAlive(v)
 	if ecode < 0 {
 		return MakeGitError(ecode)
 	}
@@ -94,6 +100,7 @@ func (v *RevWalk) PushHead() (err error) {
 	defer runtime.UnlockOSThread()
 
 	ecode := C.git_revwalk_push_head(v.ptr)
+	runtime.KeepAlive(v)
 	if ecode < 0 {
 		err = MakeGitError(ecode)
 	}
@@ -105,6 +112,8 @@ func (v *RevWalk) Hide(id *Oid) error {
 	defer runtime.UnlockOSThread()
 
 	ecode := C.git_revwalk_hide(v.ptr, id.toC())
+	runtime.KeepAlive(v)
+	runtime.KeepAlive(id)
 	if ecode < 0 {
 		return MakeGitError(ecode)
 	}
@@ -119,6 +128,7 @@ func (v *RevWalk) HideGlob(glob string) error {
 	defer C.free(unsafe.Pointer(cstr))
 
 	ecode := C.git_revwalk_hide_glob(v.ptr, cstr)
+	runtime.KeepAlive(v)
 	if ecode < 0 {
 		return MakeGitError(ecode)
 	}
@@ -133,6 +143,7 @@ func (v *RevWalk) HideRef(r string) error {
 	defer C.free(unsafe.Pointer(cstr))
 
 	ecode := C.git_revwalk_hide_ref(v.ptr, cstr)
+	runtime.KeepAlive(v)
 	if ecode < 0 {
 		return MakeGitError(ecode)
 	}
@@ -144,6 +155,7 @@ func (v *RevWalk) HideHead() (err error) {
 	defer runtime.UnlockOSThread()
 
 	ecode := C.git_revwalk_hide_head(v.ptr)
+	runtime.KeepAlive(v)
 	if ecode < 0 {
 		err = MakeGitError(ecode)
 	}
@@ -155,6 +167,7 @@ func (v *RevWalk) Next(id *Oid) (err error) {
 	defer runtime.UnlockOSThread()
 
 	ret := C.git_revwalk_next(id.toC(), v.ptr)
+	runtime.KeepAlive(v)
 	switch {
 	case ret < 0:
 		err = MakeGitError(ret)
@@ -192,14 +205,15 @@ func (v *RevWalk) Iterate(fun RevWalkIterator) (err error) {
 
 func (v *RevWalk) SimplifyFirstParent() {
 	C.git_revwalk_simplify_first_parent(v.ptr)
+	runtime.KeepAlive(v)
 }
 
 func (v *RevWalk) Sorting(sm SortType) {
 	C.git_revwalk_sorting(v.ptr, C.uint(sm))
+	runtime.KeepAlive(v)
 }
 
 func (v *RevWalk) Free() {
-
 	runtime.SetFinalizer(v, nil)
 	C.git_revwalk_free(v.ptr)
 }