Merge remote-tracking branch 'origin/master' into next

32 files changed, 488 insertions, 126 deletions

diff --git a/.travis.yml b/.travis.yml
index f84d07e..f8b7e93 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,9 +1,19 @@
 language: go
 
+install:
+  - cd "${HOME}"
+  - wget -O libgit2-0.22.1.tar.gz https://github.com/libgit2/libgit2/archive/v0.22.1.tar.gz
+  - tar -xzvf libgit2-0.22.1.tar.gz
+  - cd libgit2-0.22.1 && mkdir build && cd build
+  - cmake -DTHREADSAFE=ON -DBUILD_CLAR=OFF -DCMAKE_C_FLAGS=-fPIC -DCMAKE_BUILD_TYPE="RelWithDebInfo" -DCMAKE_INSTALL_PREFIX=/usr/local .. && make && sudo make install
+  - sudo ldconfig
+  - cd "${TRAVIS_BUILD_DIR}"
+
 go:
   - 1.1
   - 1.2
   - 1.3
+  - 1.4
   - tip
 
 matrix:
diff --git a/blame_test.go b/blame_test.go
index 1785042..a2a4d38 100644
--- a/blame_test.go
+++ b/blame_test.go
@@ -1,15 +1,13 @@
 package git
 
 import (
-	"os"
 	"reflect"
 	"testing"
 )
 
 func TestBlame(t *testing.T) {
 	repo := createTestRepo(t)
-	defer repo.Free()
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	commitId1, _ := seedTestRepo(t, repo)
 	commitId2, _ := updateReadme(t, repo, "foo\nbar\nbaz\n")
diff --git a/blob.go b/blob.go
index 5a33bd8..b1fc78a 100644
--- a/blob.go
+++ b/blob.go
@@ -60,8 +60,13 @@ type BlobCallbackData struct {
 }
 
 //export blobChunkCb
-func blobChunkCb(buffer *C.char, maxLen C.size_t, payload unsafe.Pointer) int {
-	data := (*BlobCallbackData)(payload)
+func blobChunkCb(buffer *C.char, maxLen C.size_t, handle unsafe.Pointer) int {
+	payload := pointerHandles.Get(handle)
+	data, ok := payload.(*BlobCallbackData)
+	if !ok {
+		panic("could not retrieve blob callback data")
+	}
+
 	goBuf, err := data.Callback(int(maxLen))
 	if err == io.EOF {
 		return 0
@@ -83,8 +88,12 @@ func (repo *Repository) CreateBlobFromChunks(hintPath string, callback BlobChunk
 		defer C.free(unsafe.Pointer(chintPath))
 	}
 	oid := C.git_oid{}
+
 	payload := &BlobCallbackData{Callback: callback}
-	ecode := C._go_git_blob_create_fromchunks(&oid, repo.ptr, chintPath, unsafe.Pointer(payload))
+	handle := pointerHandles.Track(payload)
+	defer pointerHandles.Untrack(handle)
+
+	ecode := C._go_git_blob_create_fromchunks(&oid, repo.ptr, chintPath, handle)
 	if payload.Error != nil {
 		return nil, payload.Error
 	}
diff --git a/blob_test.go b/blob_test.go
index e075192..2b5ec4f 100644
--- a/blob_test.go
+++ b/blob_test.go
@@ -1,13 +1,12 @@
 package git
 
 import (
-	"os"
 	"testing"
 )
 
 func TestCreateBlobFromBuffer(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	id, err := repo.CreateBlobFromBuffer(make([]byte, 0))
 	checkFatal(t, err)
diff --git a/branch_test.go b/branch_test.go
index 09ebeba..a0834a8 100644
--- a/branch_test.go
+++ b/branch_test.go
@@ -1,9 +1,13 @@
 package git
 
-import "testing"
+import (
+	"testing"
+)
 
 func TestBranchIterator(t *testing.T) {
 	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
 	seedTestRepo(t, repo)
 
 	i, err := repo.NewBranchIterator(BranchLocal)
@@ -24,6 +28,8 @@ func TestBranchIterator(t *testing.T) {
 
 func TestBranchIteratorEach(t *testing.T) {
 	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
 	seedTestRepo(t, repo)
 
 	i, err := repo.NewBranchIterator(BranchLocal)
diff --git a/checkout.go b/checkout.go
index 98c1ee6..d747344 100644
--- a/checkout.go
+++ b/checkout.go
@@ -43,6 +43,7 @@ type CheckoutOpts struct {
 	FileMode        os.FileMode      // Default is 0644 or 0755 as dictated by blob
 	FileOpenFlags   int              // Default is O_CREAT | O_TRUNC | O_WRONLY
 	TargetDirectory string           // Alternative checkout path to workdir
+	Paths			[]string
 }
 
 func checkoutOptionsFromC(c *C.git_checkout_options) CheckoutOpts {
@@ -83,6 +84,11 @@ func populateCheckoutOpts(ptr *C.git_checkout_options, opts *CheckoutOpts) *C.gi
 	if opts.TargetDirectory != "" {
 		ptr.target_directory = C.CString(opts.TargetDirectory)
 	}
+	if len(opts.Paths) > 0 {
+		ptr.paths.strings = makeCStringsFromStrings(opts.Paths)
+		ptr.paths.count = C.size_t(len(opts.Paths))
+	}
+
 	return ptr
 }
 
@@ -91,6 +97,9 @@ func freeCheckoutOpts(ptr *C.git_checkout_options) {
 		return
 	}
 	C.free(unsafe.Pointer(ptr.target_directory))
+	if ptr.paths.count > 0 {
+		freeStrarray(&ptr.paths)
+	}
 }
 
 // Updates files in the index and the working tree to match the content of
@@ -146,4 +155,4 @@ func (v *Repository) CheckoutTree(tree *Tree, opts *CheckoutOpts) error {
 	}
 
 	return nil
-}
+}
\ No newline at end of file
diff --git a/cherrypick_test.go b/cherrypick_test.go
index 141a55d..a3246bd 100644
--- a/cherrypick_test.go
+++ b/cherrypick_test.go
@@ -34,6 +34,8 @@ func readReadme(t *testing.T, repo *Repository) string {
 
 func TestCherrypick(t *testing.T) {
 	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
 	c1, _ := seedTestRepo(t, repo)
 	c2, _ := updateReadme(t, repo, content)
 
diff --git a/clone_test.go b/clone_test.go
index 97366bf..fd83fec 100644
--- a/clone_test.go
+++ b/clone_test.go
@@ -2,22 +2,21 @@ package git
 
 import (
 	"io/ioutil"
-	"os"
 	"testing"
 )
 
 func TestClone(t *testing.T) {
 
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	seedTestRepo(t, repo)
 
 	path, err := ioutil.TempDir("", "git2go")
 	checkFatal(t, err)
 
-	_, err = Clone(repo.Path(), path, &CloneOptions{Bare: true})
-	defer os.RemoveAll(path)
+	repo2, err := Clone(repo.Path(), path, &CloneOptions{Bare: true})
+	defer cleanupTestRepo(t, repo2)
 
 	checkFatal(t, err)
 }
diff --git a/commit.go b/commit.go
index 57e1a77..52f7c01 100644
--- a/commit.go
+++ b/commit.go
@@ -9,6 +9,7 @@ import "C"
 
 import (
 	"runtime"
+	"unsafe"
 )
 
 // Commit
@@ -70,3 +71,40 @@ func (c *Commit) ParentId(n uint) *Oid {
 func (c *Commit) ParentCount() uint {
 	return uint(C.git_commit_parentcount(c.cast_ptr))
 }
+
+func (c *Commit) Amend(refname string, author, committer *Signature, message string, tree *Tree) (*Oid, error) {
+	var cref *C.char
+	if refname == "" {
+		cref = nil
+	} else {
+		cref = C.CString(refname)
+		defer C.free(unsafe.Pointer(cref))
+	}
+
+	cmsg := C.CString(message)
+	defer C.free(unsafe.Pointer(cmsg))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	authorSig, err := author.toC()
+	if err != nil {
+		return nil, err
+	}
+	defer C.git_signature_free(authorSig)
+
+	committerSig, err := committer.toC()
+	if err != nil {
+		return nil, err
+	}
+	defer C.git_signature_free(committerSig)
+
+	oid := new(Oid)
+
+	cerr := C.git_commit_amend(oid.toC(), c.cast_ptr, cref, authorSig, committerSig, nil, cmsg, tree.cast_ptr)
+	if cerr < 0 {
+		return nil, MakeGitError(cerr)
+	}
+
+	return oid, nil
+}
diff --git a/diff.go b/diff.go
index 63fa867..5e03175 100644
--- a/diff.go
+++ b/diff.go
@@ -265,7 +265,11 @@ func (diff *Diff) ForEach(cbFile DiffForEachFileCallback, detail DiffDetail) err
 	data := &diffForEachData{
 		FileCallback: cbFile,
 	}
-	ecode := C._go_git_diff_foreach(diff.ptr, 1, intHunks, intLines, unsafe.Pointer(data))
+
+	handle := pointerHandles.Track(data)
+	defer pointerHandles.Untrack(handle)
+
+	ecode := C._go_git_diff_foreach(diff.ptr, 1, intHunks, intLines, handle)
 	if ecode < 0 {
 		return data.Error
 	}
@@ -273,8 +277,12 @@ func (diff *Diff) ForEach(cbFile DiffForEachFileCallback, detail DiffDetail) err
 }
 
 //export diffForEachFileCb
-func diffForEachFileCb(delta *C.git_diff_delta, progress C.float, payload unsafe.Pointer) int {
-	data := (*diffForEachData)(payload)
+func diffForEachFileCb(delta *C.git_diff_delta, progress C.float, handle unsafe.Pointer) int {
+	payload := pointerHandles.Get(handle)
+	data, ok := payload.(*diffForEachData)
+	if !ok {
+		panic("could not retrieve data for handle")
+	}
 
 	data.HunkCallback = nil
 	if data.FileCallback != nil {
@@ -292,8 +300,12 @@ func diffForEachFileCb(delta *C.git_diff_delta, progress C.float, payload unsafe
 type DiffForEachHunkCallback func(DiffHunk) (DiffForEachLineCallback, error)
 
 //export diffForEachHunkCb
-func diffForEachHunkCb(delta *C.git_diff_delta, hunk *C.git_diff_hunk, payload unsafe.Pointer) int {
-	data := (*diffForEachData)(payload)
+func diffForEachHunkCb(delta *C.git_diff_delta, hunk *C.git_diff_hunk, handle unsafe.Pointer) int {
+	payload := pointerHandles.Get(handle)
+	data, ok := payload.(*diffForEachData)
+	if !ok {
+		panic("could not retrieve data for handle")
+	}
 
 	data.LineCallback = nil
 	if data.HunkCallback != nil {
@@ -311,9 +323,12 @@ func diffForEachHunkCb(delta *C.git_diff_delta, hunk *C.git_diff_hunk, payload u
 type DiffForEachLineCallback func(DiffLine) error
 
 //export diffForEachLineCb
-func diffForEachLineCb(delta *C.git_diff_delta, hunk *C.git_diff_hunk, line *C.git_diff_line, payload unsafe.Pointer) int {
-
-	data := (*diffForEachData)(payload)
+func diffForEachLineCb(delta *C.git_diff_delta, hunk *C.git_diff_hunk, line *C.git_diff_line, handle unsafe.Pointer) int {
+	payload := pointerHandles.Get(handle)
+	data, ok := payload.(*diffForEachData)
+	if !ok {
+		panic("could not retrieve data for handle")
+	}
 
 	err := data.LineCallback(diffLineFromC(delta, hunk, line))
 	if err != nil {
@@ -479,9 +494,15 @@ type diffNotifyData struct {
 }
 
 //export diffNotifyCb
-func diffNotifyCb(_diff_so_far unsafe.Pointer, delta_to_add *C.git_diff_delta, matched_pathspec *C.char, payload unsafe.Pointer) int {
+func diffNotifyCb(_diff_so_far unsafe.Pointer, delta_to_add *C.git_diff_delta, matched_pathspec *C.char, handle unsafe.Pointer) int {
 	diff_so_far := (*C.git_diff)(_diff_so_far)
-	data := (*diffNotifyData)(payload)
+
+	payload := pointerHandles.Get(handle)
+	data, ok := payload.(*diffNotifyData)
+	if !ok {
+		panic("could not retrieve data for handle")
+	}
+
 	if data != nil {
 		if data.Diff == nil {
 			data.Diff = newDiffFromC(diff_so_far)
@@ -507,6 +528,7 @@ func diffOptionsToC(opts *DiffOptions) (copts *C.git_diff_options, notifyData *d
 		notifyData = &diffNotifyData{
 			Callback: opts.NotifyCallback,
 		}
+
 		if opts.Pathspec != nil {
 			cpathspec.count = C.size_t(len(opts.Pathspec))
 			cpathspec.strings = makeCStringsFromStrings(opts.Pathspec)
@@ -527,7 +549,7 @@ func diffOptionsToC(opts *DiffOptions) (copts *C.git_diff_options, notifyData *d
 
 		if opts.NotifyCallback != nil {
 			C._go_git_setup_diff_notify_callbacks(copts)
-			copts.notify_payload = unsafe.Pointer(notifyData)
+			copts.notify_payload = pointerHandles.Track(notifyData)
 		}
 	}
 	return
@@ -539,6 +561,9 @@ func freeDiffOptions(copts *C.git_diff_options) {
 		freeStrarray(&cpathspec)
 		C.free(unsafe.Pointer(copts.old_prefix))
 		C.free(unsafe.Pointer(copts.new_prefix))
+		if copts.notify_payload != nil {
+			pointerHandles.Untrack(copts.notify_payload)
+		}
 	}
 }
 
@@ -595,3 +620,53 @@ func (v *Repository) DiffTreeToWorkdir(oldTree *Tree, opts *DiffOptions) (*Diff,
 	}
 	return newDiffFromC(diffPtr), nil
 }
+
+func (v *Repository) DiffTreeToWorkdirWithIndex(oldTree *Tree, opts *DiffOptions) (*Diff, error) {
+	var diffPtr *C.git_diff
+	var oldPtr *C.git_tree
+
+	if oldTree != nil {
+		oldPtr = oldTree.cast_ptr
+	}
+
+	copts, notifyData := diffOptionsToC(opts)
+	defer freeDiffOptions(copts)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_diff_tree_to_workdir_with_index(&diffPtr, v.ptr, oldPtr, copts)
+	if ecode < 0 {
+		return nil, MakeGitError(ecode)
+	}
+
+	if notifyData != nil && notifyData.Diff != nil {
+		return notifyData.Diff, nil
+	}
+	return newDiffFromC(diffPtr), nil
+}
+
+func (v *Repository) DiffIndexToWorkdir(index *Index, opts *DiffOptions) (*Diff, error) {
+	var diffPtr *C.git_diff
+	var indexPtr *C.git_index
+
+	if index != nil {
+		indexPtr = index.ptr
+	}
+
+	copts, notifyData := diffOptionsToC(opts)
+	defer freeDiffOptions(copts)
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ecode := C.git_diff_index_to_workdir(&diffPtr, v.ptr, indexPtr, copts)
+	if ecode < 0 {
+		return nil, MakeGitError(ecode)
+	}
+
+	if notifyData != nil && notifyData.Diff != nil {
+		return notifyData.Diff, nil
+	}
+	return newDiffFromC(diffPtr), nil
+}
diff --git a/diff_test.go b/diff_test.go
index fc6fed9..464fae6 100644
--- a/diff_test.go
+++ b/diff_test.go
@@ -2,15 +2,13 @@ package git
 
 import (
 	"errors"
-	"os"
 	"strings"
 	"testing"
 )
 
 func TestFindSimilar(t *testing.T) {
 	repo := createTestRepo(t)
-	defer repo.Free()
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	originalTree, newTree := createTestTrees(t, repo)
 
@@ -65,8 +63,7 @@ func TestFindSimilar(t *testing.T) {
 func TestDiffTreeToTree(t *testing.T) {
 
 	repo := createTestRepo(t)
-	defer repo.Free()
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	originalTree, newTree := createTestTrees(t, repo)
 
diff --git a/git.go b/git.go
index 8e78710..5f69837 100644
--- a/git.go
+++ b/git.go
@@ -92,7 +92,11 @@ var (
 	ErrInvalid = errors.New("Invalid state for operation")
 )
 
+var pointerHandles *HandleList
+
 func init() {
+	pointerHandles = NewHandleList()
+
 	C.git_libgit2_init()
 
 	// This is not something we should be doing, as we may be
diff --git a/git_test.go b/git_test.go
index b9cf0a9..58caf71 100644
--- a/git_test.go
+++ b/git_test.go
@@ -2,11 +2,24 @@ package git
 
 import (
 	"io/ioutil"
+	"os"
 	"path"
 	"testing"
 	"time"
 )
 
+func cleanupTestRepo(t *testing.T, r *Repository) {
+	var err error
+	if r.IsBare() {
+		err = os.RemoveAll(r.Path())
+	} else {
+		err = os.RemoveAll(r.Workdir())
+	}
+	checkFatal(t, err)
+
+	r.Free()
+}
+
 func createTestRepo(t *testing.T) *Repository {
 	// figure out where we can create the test repo
 	path, err := ioutil.TempDir("", "git2go")
diff --git a/handles.go b/handles.go
new file mode 100644
index 0000000..ec62a48
--- /dev/null
+++ b/handles.go
@@ -0,0 +1,84 @@
+package git
+
+import (
+	"fmt"
+	"sync"
+	"unsafe"
+)
+
+type HandleList struct {
+	sync.RWMutex
+	// stores the Go pointers
+	handles []interface{}
+	// indicates which indices are in use
+	set map[int]bool
+}
+
+func NewHandleList() *HandleList {
+	return &HandleList{
+		handles: make([]interface{}, 5),
+		set:     make(map[int]bool),
+	}
+}
+
+// findUnusedSlot finds the smallest-index empty space in our
+// list. You must only run this function while holding a write lock.
+func (v *HandleList) findUnusedSlot() int {
+	for i := 1; i < len(v.handles); i++ {
+		isUsed := v.set[i]
+		if !isUsed {
+			return i
+		}
+	}
+
+	// reaching here means we've run out of entries so append and
+	// return the new index, which is equal to the old length.
+	slot := len(v.handles)
+	v.handles = append(v.handles, nil)
+
+	return slot
+}
+
+// Track adds the given pointer to the list of pointers to track and
+// returns a pointer value which can be passed to C as an opaque
+// pointer.
+func (v *HandleList) Track(pointer interface{}) unsafe.Pointer {
+	v.Lock()
+
+	slot := v.findUnusedSlot()
+	v.handles[slot] = pointer
+	v.set[slot] = true
+
+	v.Unlock()
+
+	return unsafe.Pointer(&slot)
+}
+
+// Untrack stops tracking the pointer given by the handle
+func (v *HandleList) Untrack(handle unsafe.Pointer) {
+	slot := *(*int)(handle)
+
+	v.Lock()
+
+	v.handles[slot] = nil
+	delete(v.set, slot)
+
+	v.Unlock()
+}
+
+// Get retrieves the pointer from the given handle
+func (v *HandleList) Get(handle unsafe.Pointer) interface{} {
+	slot := *(*int)(handle)
+
+	v.RLock()
+
+	if _, ok := v.set[slot]; !ok {
+		panic(fmt.Sprintf("invalid pointer handle: %p", handle))
+	}
+
+	ptr := v.handles[slot]
+
+	v.RUnlock()
+
+	return ptr
+}
diff --git a/index.go b/index.go
index 6b90758..c1bfb74 100644
--- a/index.go
+++ b/index.go
@@ -96,6 +96,30 @@ func NewIndex() (*Index, error) {
 	return &Index{ptr: ptr}, nil
 }
 
+// OpenIndex creates a new index at the given path. If the file does
+// not exist it will be created when Write() is called.
+func OpenIndex(path string) (*Index, error) {
+	var ptr *C.git_index
+
+	var cpath = C.CString(path)
+	defer C.free(unsafe.Pointer(cpath))
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	if err := C.git_index_open(&ptr, cpath); err < 0 {
+		return nil, MakeGitError(err)
+	}
+
+	return &Index{ptr: ptr}, nil
+}
+
+// Path returns the index' path on disk or an empty string if it
+// exists only in memory.
+func (v *Index) Path() string {
+	return C.GoString(C.git_index_path(v.ptr))
+}
+
 // Add adds or replaces the given entry to the index, making a copy of
 // the data
 func (v *Index) Add(entry *IndexEntry) error {
@@ -138,16 +162,17 @@ func (v *Index) AddAll(pathspecs []string, flags IndexAddOpts, callback IndexMat
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	var cb *IndexMatchedPathCallback
+	var handle unsafe.Pointer
 	if callback != nil {
-		cb = &callback
+		handle = pointerHandles.Track(callback)
+		defer pointerHandles.Untrack(handle)
 	}
 
 	ret := C._go_git_index_add_all(
 		v.ptr,
 		&cpathspecs,
 		C.uint(flags),
-		unsafe.Pointer(cb),
+		handle,
 	)
 	if ret < 0 {
 		return MakeGitError(ret)
@@ -164,15 +189,16 @@ func (v *Index) UpdateAll(pathspecs []string, callback IndexMatchedPathCallback)
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	var cb *IndexMatchedPathCallback
+	var handle unsafe.Pointer
 	if callback != nil {
-		cb = &callback
+		handle = pointerHandles.Track(callback)
+		defer pointerHandles.Untrack(handle)
 	}
 
 	ret := C._go_git_index_update_all(
 		v.ptr,
 		&cpathspecs,
-		unsafe.Pointer(cb),
+		handle,
 	)
 	if ret < 0 {
 		return MakeGitError(ret)
@@ -189,15 +215,16 @@ func (v *Index) RemoveAll(pathspecs []string, callback IndexMatchedPathCallback)
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	var cb *IndexMatchedPathCallback
+	var handle unsafe.Pointer
 	if callback != nil {
-		cb = &callback
+		handle = pointerHandles.Track(callback)
+		defer pointerHandles.Untrack(handle)
 	}
 
 	ret := C._go_git_index_remove_all(
 		v.ptr,
 		&cpathspecs,
-		unsafe.Pointer(cb),
+		handle,
 	)
 	if ret < 0 {
 		return MakeGitError(ret)
@@ -207,8 +234,11 @@ func (v *Index) RemoveAll(pathspecs []string, callback IndexMatchedPathCallback)
 
 //export indexMatchedPathCallback
 func indexMatchedPathCallback(cPath, cMatchedPathspec *C.char, payload unsafe.Pointer) int {
-	callback := (*IndexMatchedPathCallback)(payload)
-	return (*callback)(C.GoString(cPath), C.GoString(cMatchedPathspec))
+	if callback, ok := pointerHandles.Get(payload).(IndexMatchedPathCallback); ok {
+		return callback(C.GoString(cPath), C.GoString(cMatchedPathspec))
+	} else {
+		panic("invalid matched path callback")
+	}
 }
 
 func (v *Index) RemoveByPath(path string) error {
@@ -240,6 +270,20 @@ func (v *Index) WriteTreeTo(repo *Repository) (*Oid, error) {
 	return oid, nil
 }
 
+// ReadTree replaces the contents of the index with those of the given
+// tree
+func (v *Index) ReadTree(tree *Tree) error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	ret := C.git_index_read_tree(v.ptr, tree.cast_ptr);
+	if ret < 0 {
+		return MakeGitError(ret)
+	}
+
+	return nil
+}
+
 func (v *Index) WriteTree() (*Oid, error) {
 	oid := new(Oid)
 
@@ -287,6 +331,7 @@ func (v *Index) HasConflicts() bool {
 	return C.git_index_has_conflicts(v.ptr) != 0
 }
 
+// FIXME: this might return an error
 func (v *Index) CleanupConflicts() {
 	C.git_index_conflict_cleanup(v.ptr)
 }
diff --git a/index_test.go b/index_test.go
index 98d9a31..7c65f4f 100644
--- a/index_test.go
+++ b/index_test.go
@@ -9,7 +9,7 @@ import (
 
 func TestCreateRepoAndStage(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	idx, err := repo.Index()
 	checkFatal(t, err)
@@ -23,12 +23,40 @@ func TestCreateRepoAndStage(t *testing.T) {
 	}
 }
 
+func TestIndexReadTree(t *testing.T) {
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	_, _ = seedTestRepo(t, repo)
+
+	ref, err := repo.Head()
+	checkFatal(t, err)
+
+	obj, err := ref.Peel(ObjectTree);
+	checkFatal(t, err)
+
+	tree := obj.(*Tree)
+
+	idx, err := NewIndex()
+	checkFatal(t, err)
+
+	err = idx.ReadTree(tree)
+	checkFatal(t, err)
+
+	id, err := idx.WriteTreeTo(repo)
+	checkFatal(t, err)
+
+	if tree.Id().Cmp(id) != 0 {
+		t.Fatalf("Read and written trees are not the same")
+	}
+}
+
 func TestIndexWriteTreeTo(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	repo2 := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo2)
 
 	idx, err := repo.Index()
 	checkFatal(t, err)
@@ -44,7 +72,7 @@ func TestIndexWriteTreeTo(t *testing.T) {
 
 func TestIndexAddAndWriteTreeTo(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	odb, err := repo.Odb()
 	checkFatal(t, err)
@@ -55,6 +83,10 @@ func TestIndexAddAndWriteTreeTo(t *testing.T) {
 	idx, err := NewIndex()
 	checkFatal(t, err)
 
+	if idx.Path() != "" {
+		t.Fatal("in-memory repo has a path")
+	}
+
 	entry := IndexEntry{
 		Path: "README",
 		Id:   blobID,
@@ -74,7 +106,7 @@ func TestIndexAddAndWriteTreeTo(t *testing.T) {
 
 func TestIndexAddAllNoCallback(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	err := ioutil.WriteFile(repo.Workdir()+"/README", []byte("foo\n"), 0644)
 	checkFatal(t, err)
@@ -95,7 +127,7 @@ func TestIndexAddAllNoCallback(t *testing.T) {
 
 func TestIndexAddAllCallback(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	err := ioutil.WriteFile(repo.Workdir()+"/README", []byte("foo\n"), 0644)
 	checkFatal(t, err)
@@ -121,6 +153,33 @@ func TestIndexAddAllCallback(t *testing.T) {
 	}
 }
 
+func TestIndexOpen(t *testing.T) {
+	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
+	path := repo.Workdir() + "/heyindex"
+
+	_, err := os.Stat(path)
+	if !os.IsNotExist(err) {
+		t.Fatal("new index file already exists")
+	}
+
+	idx, err := OpenIndex(path)
+	checkFatal(t, err)
+
+	if path != idx.Path() {
+		t.Fatalf("mismatched index paths, expected %v, got %v", path, idx.Path())
+	}
+
+	err = idx.Write()
+	checkFatal(t, err)
+
+	_, err = os.Stat(path)
+	if os.IsNotExist(err) {
+		t.Fatal("new index file did not get written")
+	}
+}
+
 func checkFatal(t *testing.T, err error) {
 	if err == nil {
 		return
@@ -129,8 +188,7 @@ func checkFatal(t *testing.T, err error) {
 	// The failure happens at wherever we were called, not here
 	_, file, line, ok := runtime.Caller(1)
 	if !ok {
-		t.Fatal()
+		t.Fatalf("Unable to get caller")
 	}
-
 	t.Fatalf("Fail at %v:%v; %v", file, line, err)
 }
diff --git a/merge_test.go b/merge_test.go
index 1eba806..0b1faca 100644
--- a/merge_test.go
+++ b/merge_test.go
@@ -1,13 +1,13 @@
 package git
 
 import (
-	"os"
 	"testing"
 )
 
 func TestMergeWithSelf(t *testing.T) {
-
 	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
 	seedTestRepo(t, repo)
 
 	master, err := repo.LookupReference("refs/heads/master")
@@ -23,8 +23,9 @@ func TestMergeWithSelf(t *testing.T) {
 }
 
 func TestMergeAnalysisWithSelf(t *testing.T) {
-
 	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
 	seedTestRepo(t, repo)
 
 	master, err := repo.LookupReference("refs/heads/master")
@@ -44,7 +45,6 @@ func TestMergeAnalysisWithSelf(t *testing.T) {
 }
 
 func TestMergeSameFile(t *testing.T) {
-
 	file := MergeFileInput{
 		Path:     "test",
 		Mode:     33188,
@@ -68,8 +68,7 @@ func TestMergeSameFile(t *testing.T) {
 }
 func TestMergeTreesWithoutAncestor(t *testing.T) {
 	repo := createTestRepo(t)
-	defer repo.Free()
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	_, originalTreeId := seedTestRepo(t, repo)
 	originalTree, err := repo.LookupTree(originalTreeId)
diff --git a/note_test.go b/note_test.go
index f5e9c01..e6c378d 100644
--- a/note_test.go
+++ b/note_test.go
@@ -2,7 +2,6 @@ package git
 
 import (
 	"fmt"
-	"os"
 	"reflect"
 	"testing"
 	"time"
@@ -10,7 +9,7 @@ import (
 
 func TestCreateNote(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	commitId, _ := seedTestRepo(t, repo)
 
@@ -29,7 +28,8 @@ func TestCreateNote(t *testing.T) {
 
 func TestNoteIterator(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
+
 	seedTestRepo(t, repo)
 
 	notes := make([]*Note, 5)
@@ -64,7 +64,7 @@ func TestNoteIterator(t *testing.T) {
 
 func TestRemoveNote(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	commitId, _ := seedTestRepo(t, repo)
 
@@ -87,7 +87,7 @@ func TestRemoveNote(t *testing.T) {
 
 func TestDefaultNoteRef(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	ref, err := repo.DefaultNoteRef()
 	checkFatal(t, err)
diff --git a/object_test.go b/object_test.go
index f525351..aa295e5 100644
--- a/object_test.go
+++ b/object_test.go
@@ -1,13 +1,13 @@
 package git
 
 import (
-	"os"
 	"testing"
 )
 
 func TestObjectPoymorphism(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
+
 	commitId, treeId := seedTestRepo(t, repo)
 
 	var obj Object
@@ -89,7 +89,8 @@ func checkOwner(t *testing.T, repo *Repository, obj Object) {
 
 func TestObjectOwner(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
+
 	commitId, treeId := seedTestRepo(t, repo)
 
 	commit, err := repo.LookupCommit(commitId)
diff --git a/odb.go b/odb.go
index ba03860..6b21329 100644
--- a/odb.go
+++ b/odb.go
@@ -98,8 +98,12 @@ type foreachData struct {
 }
 
 //export odbForEachCb
-func odbForEachCb(id *C.git_oid, payload unsafe.Pointer) int {
-	data := (*foreachData)(payload)
+func odbForEachCb(id *C.git_oid, handle unsafe.Pointer) int {
+	data, ok := pointerHandles.Get(handle).(*foreachData)
+
+	if !ok {
+		panic("could not retrieve handle")
+	}
 
 	err := data.callback(newOidFromC(id))
 	if err != nil {
@@ -119,7 +123,10 @@ func (v *Odb) ForEach(callback OdbForEachCallback) error {
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	ret := C._go_git_odb_foreach(v.ptr, unsafe.Pointer(&data))
+	handle := pointerHandles.Track(&data)
+	defer pointerHandles.Untrack(handle)
+
+	ret := C._go_git_odb_foreach(v.ptr, handle)
 	if ret == C.GIT_EUSER {
 		return data.err
 	} else if ret < 0 {
diff --git a/odb_test.go b/odb_test.go
index 5e6b7ff..2fb6840 100644
--- a/odb_test.go
+++ b/odb_test.go
@@ -3,13 +3,13 @@ package git
 import (
 	"errors"
 	"io"
-	"os"
 	"testing"
 )
 
 func TestOdbStream(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
+
 	_, _ = seedTestRepo(t, repo)
 
 	odb, error := repo.Odb()
@@ -38,7 +38,8 @@ func TestOdbStream(t *testing.T) {
 func TestOdbHash(t *testing.T) {
 
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
+
 	_, _ = seedTestRepo(t, repo)
 
 	odb, error := repo.Odb()
@@ -64,7 +65,8 @@ Initial commit.`
 
 func TestOdbForeach(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
+
 	_, _ = seedTestRepo(t, repo)
 
 	odb, err := repo.Odb()
@@ -79,7 +81,7 @@ func TestOdbForeach(t *testing.T) {
 
 	checkFatal(t, err)
 	if count != expect {
-		t.Fatalf("Expected %v objects, got %v")
+		t.Fatalf("Expected %v objects, got %v", expect, count)
 	}
 
 	expect = 1
diff --git a/packbuilder.go b/packbuilder.go
index 54a8390..4dc352c 100644
--- a/packbuilder.go
+++ b/packbuilder.go
@@ -110,8 +110,13 @@ type packbuilderCbData struct {
 }
 
 //export packbuilderForEachCb
-func packbuilderForEachCb(buf unsafe.Pointer, size C.size_t, payload unsafe.Pointer) int {
-	data := (*packbuilderCbData)(payload)
+func packbuilderForEachCb(buf unsafe.Pointer, size C.size_t, handle unsafe.Pointer) int {
+	payload := pointerHandles.Get(handle)
+	data, ok := payload.(*packbuilderCbData)
+	if !ok {
+		panic("could not get packbuilder CB data")
+	}
+
 	slice := C.GoBytes(buf, C.int(size))
 
 	err := data.callback(slice)
@@ -130,11 +135,13 @@ func (pb *Packbuilder) ForEach(callback PackbuilderForeachCallback) error {
 		callback: callback,
 		err:      nil,
 	}
+	handle := pointerHandles.Track(&data)
+	defer pointerHandles.Untrack(handle)
 
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	err := C._go_git_packbuilder_foreach(pb.ptr, unsafe.Pointer(&data))
+	err := C._go_git_packbuilder_foreach(pb.ptr, handle)
 	if err == C.GIT_EUSER {
 		return data.err
 	}
diff --git a/patch_test.go b/patch_test.go
index a061142..2d52fb4 100644
--- a/patch_test.go
+++ b/patch_test.go
@@ -7,8 +7,7 @@ import (
 
 func TestPatch(t *testing.T) {
 	repo := createTestRepo(t)
-	defer repo.Free()
-	//defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	_, originalTreeId := seedTestRepo(t, repo)
 	originalTree, err := repo.LookupTree(originalTreeId)
diff --git a/push_test.go b/push_test.go
index ad72e4d..4686c65 100644
--- a/push_test.go
+++ b/push_test.go
@@ -1,15 +1,15 @@
 package git
 
 import (
-	"os"
 	"testing"
 )
 
 func TestRemotePush(t *testing.T) {
 	repo := createBareTestRepo(t)
-	defer os.RemoveAll(repo.Path())
+	defer cleanupTestRepo(t, repo)
+
 	localRepo := createTestRepo(t)
-	defer os.RemoveAll(localRepo.Workdir())
+	defer cleanupTestRepo(t, localRepo)
 
 	remote, err := localRepo.CreateRemote("test_push", repo.Path())
 	checkFatal(t, err)
diff --git a/reference_test.go b/reference_test.go
index 562e276..e891e7a 100644
--- a/reference_test.go
+++ b/reference_test.go
@@ -1,7 +1,6 @@
 package git
 
 import (
-	"os"
 	"runtime"
 	"sort"
 	"testing"
@@ -10,7 +9,7 @@ import (
 
 func TestRefModification(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	commitId, treeId := seedTestRepo(t, repo)
 
@@ -55,7 +54,7 @@ func TestRefModification(t *testing.T) {
 
 func TestReferenceIterator(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	loc, err := time.LoadLocation("Europe/Berlin")
 	checkFatal(t, err)
@@ -133,7 +132,8 @@ func TestReferenceIterator(t *testing.T) {
 
 func TestReferenceOwner(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
+
 	commitId, _ := seedTestRepo(t, repo)
 
 	ref, err := repo.CreateReference("refs/heads/foo", commitId, true, "")
@@ -151,7 +151,7 @@ func TestReferenceOwner(t *testing.T) {
 
 func TestUtil(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	commitId, _ := seedTestRepo(t, repo)
 
@@ -192,8 +192,7 @@ func checkRefType(t *testing.T, ref *Reference, kind ReferenceType) {
 	// The failure happens at wherever we were called, not here
 	_, file, line, ok := runtime.Caller(1)
 	if !ok {
-		t.Fatal()
+		t.Fatalf("Unable to get caller")
 	}
-
 	t.Fatalf("Wrong ref type at %v:%v; have %v, expected %v", file, line, ref.Type(), kind)
 }
diff --git a/remote_test.go b/remote_test.go
index bbbdeb9..23c80f5 100644
--- a/remote_test.go
+++ b/remote_test.go
@@ -2,14 +2,12 @@ package git
 
 import (
 	"fmt"
-	"os"
 	"testing"
 )
 
 func TestRefspecs(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
-	defer repo.Free()
+	defer cleanupTestRepo(t, repo)
 
 	remote, err := repo.CreateAnonymousRemote("git://foo/bar", "refs/heads/*:refs/heads/*")
 	checkFatal(t, err)
@@ -30,8 +28,7 @@ func TestRefspecs(t *testing.T) {
 
 func TestListRemotes(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
-	defer repo.Free()
+	defer cleanupTestRepo(t, repo)
 
 	_, err := repo.CreateRemote("test", "git://foo/bar")
 
@@ -58,8 +55,7 @@ func assertHostname(cert *Certificate, valid bool, hostname string, t *testing.T
 
 func TestCertificateCheck(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
-	defer repo.Free()
+	defer cleanupTestRepo(t, repo)
 
 	remote, err := repo.CreateRemote("origin", "https://github.com/libgit2/TestGitRepository")
 	checkFatal(t, err)
@@ -78,8 +74,7 @@ func TestCertificateCheck(t *testing.T) {
 
 func TestRemoteConnect(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
-	defer repo.Free()
+	defer cleanupTestRepo(t, repo)
 
 	remote, err := repo.CreateRemote("origin", "https://github.com/libgit2/TestGitRepository")
 	checkFatal(t, err)
@@ -90,8 +85,7 @@ func TestRemoteConnect(t *testing.T) {
 
 func TestRemoteLs(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
-	defer repo.Free()
+	defer cleanupTestRepo(t, repo)
 
 	remote, err := repo.CreateRemote("origin", "https://github.com/libgit2/TestGitRepository")
 	checkFatal(t, err)
@@ -109,8 +103,7 @@ func TestRemoteLs(t *testing.T) {
 
 func TestRemoteLsFiltering(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
-	defer repo.Free()
+	defer cleanupTestRepo(t, repo)
 
 	remote, err := repo.CreateRemote("origin", "https://github.com/libgit2/TestGitRepository")
 	checkFatal(t, err)
@@ -136,8 +129,7 @@ func TestRemoteLsFiltering(t *testing.T) {
 
 func TestRemotePruneRefs(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
-	defer repo.Free()
+	defer cleanupTestRepo(t, repo)
 
 	config, err := repo.Config()
 	checkFatal(t, err)
@@ -159,8 +151,7 @@ func TestRemotePruneRefs(t *testing.T) {
 
 func TestRemotePrune(t *testing.T) {
 	remoteRepo := createTestRepo(t)
-	defer os.RemoveAll(remoteRepo.Workdir())
-	defer remoteRepo.Free()
+	defer cleanupTestRepo(t, remoteRepo)
 
 	head, _ := seedTestRepo(t, remoteRepo)
 	commit, err := remoteRepo.LookupCommit(head)
@@ -171,8 +162,7 @@ func TestRemotePrune(t *testing.T) {
 	checkFatal(t, err)
 
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
-	defer repo.Free()
+	defer cleanupTestRepo(t, repo)
 
 	config, err := repo.Config()
 	checkFatal(t, err)
diff --git a/revparse_test.go b/revparse_test.go
index 8c3a352..4bc327c 100644
--- a/revparse_test.go
+++ b/revparse_test.go
@@ -1,13 +1,12 @@
 package git
 
 import (
-	"os"
 	"testing"
 )
 
 func TestRevparse(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	commitId, _ := seedTestRepo(t, repo)
 
@@ -19,7 +18,7 @@ func TestRevparse(t *testing.T) {
 
 func TestRevparseSingle(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	commitId, _ := seedTestRepo(t, repo)
 
@@ -31,7 +30,7 @@ func TestRevparseSingle(t *testing.T) {
 
 func TestRevparseExt(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	_, treeId := seedTestRepo(t, repo)
 
diff --git a/status_test.go b/status_test.go
index d18fca1..5b97b00 100644
--- a/status_test.go
+++ b/status_test.go
@@ -2,15 +2,13 @@ package git
 
 import (
 	"io/ioutil"
-	"os"
 	"path"
 	"testing"
 )
 
 func TestStatusFile(t *testing.T) {
 	repo := createTestRepo(t)
-	defer repo.Free()
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
 
 	state := repo.State()
 	if state != RepositoryStateNone {
@@ -30,10 +28,10 @@ func TestStatusFile(t *testing.T) {
 
 func TestStatusList(t *testing.T) {
 	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
 	// This commits the test repo README, so it doesn't show up in the status list and there's a head to compare to
 	seedTestRepo(t, repo)
-	defer repo.Free()
-	defer os.RemoveAll(repo.Workdir())
 
 	err := ioutil.WriteFile(path.Join(path.Dir(repo.Workdir()), "hello.txt"), []byte("Hello, World"), 0644)
 	checkFatal(t, err)
diff --git a/submodule.go b/submodule.go
index fdd38cc..6edc1d7 100644
--- a/submodule.go
+++ b/submodule.go
@@ -96,17 +96,24 @@ func (repo *Repository) LookupSubmodule(name string) (*Submodule, error) {
 type SubmoduleCbk func(sub *Submodule, name string) int
 
 //export SubmoduleVisitor
-func SubmoduleVisitor(csub unsafe.Pointer, name *C.char, cfct unsafe.Pointer) C.int {
+func SubmoduleVisitor(csub unsafe.Pointer, name *C.char, handle unsafe.Pointer) C.int {
 	sub := &Submodule{(*C.git_submodule)(csub)}
-	fct := *(*SubmoduleCbk)(cfct)
-	return (C.int)(fct(sub, C.GoString(name)))
+
+	if callback, ok := pointerHandles.Get(handle).(SubmoduleCbk); ok {
+		return (C.int)(callback(sub, C.GoString(name)))
+	} else {
+		panic("invalid submodule visitor callback")
+	}
 }
 
 func (repo *Repository) ForeachSubmodule(cbk SubmoduleCbk) error {
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
-	ret := C._go_git_visit_submodule(repo.ptr, unsafe.Pointer(&cbk))
+	handle := pointerHandles.Track(cbk)
+	defer pointerHandles.Untrack(handle)
+
+	ret := C._go_git_visit_submodule(repo.ptr, handle)
 	if ret < 0 {
 		return MakeGitError(ret)
 	}
diff --git a/submodule_test.go b/submodule_test.go
index 1c8f471..27bc193 100644
--- a/submodule_test.go
+++ b/submodule_test.go
@@ -6,6 +6,8 @@ import (
 
 func TestSubmoduleForeach(t *testing.T) {
 	repo := createTestRepo(t)
+	defer cleanupTestRepo(t, repo)
+
 	seedTestRepo(t, repo)
 
 	_, err := repo.AddSubmodule("http://example.org/submodule", "submodule", true)
@@ -19,6 +21,6 @@ func TestSubmoduleForeach(t *testing.T) {
 	checkFatal(t, err)
 
 	if i != 1 {
-		t.Fatalf("expected one submodule found but got %i", i)
+		t.Fatalf("expected one submodule found but got %d", i)
 	}
 }
diff --git a/tag_test.go b/tag_test.go
index 126cf6e..74f9fec 100644
--- a/tag_test.go
+++ b/tag_test.go
@@ -1,14 +1,14 @@
 package git
 
 import (
-	"os"
 	"testing"
 	"time"
 )
 
 func TestCreateTag(t *testing.T) {
 	repo := createTestRepo(t)
-	defer os.RemoveAll(repo.Workdir())
+	defer cleanupTestRepo(t, repo)
+
 	commitId, _ := seedTestRepo(t, repo)
 
 	commit, err := repo.LookupCommit(commitId)
diff --git a/tree.go b/tree.go
index c18d02a..aad2c8d 100644
--- a/tree.go
+++ b/tree.go
@@ -90,22 +90,28 @@ func (t Tree) EntryCount() uint64 {
 type TreeWalkCallback func(string, *TreeEntry) int
 
 //export CallbackGitTreeWalk
-func CallbackGitTreeWalk(_root unsafe.Pointer, _entry unsafe.Pointer, ptr unsafe.Pointer) C.int {
-	root := C.GoString((*C.char)(_root))
+func CallbackGitTreeWalk(_root *C.char, _entry unsafe.Pointer, ptr unsafe.Pointer) C.int {
+	root := C.GoString(_root)
 	entry := (*C.git_tree_entry)(_entry)
-	callback := *(*TreeWalkCallback)(ptr)
 
-	return C.int(callback(root, newTreeEntry(entry)))
+	if callback, ok := pointerHandles.Get(ptr).(TreeWalkCallback); ok {
+		return C.int(callback(root, newTreeEntry(entry)))
+	} else {
+		panic("invalid treewalk callback")
+	}
 }
 
 func (t Tree) Walk(callback TreeWalkCallback) error {
 	runtime.LockOSThread()
 	defer runtime.UnlockOSThread()
 
+	ptr := pointerHandles.Track(callback)
+	defer pointerHandles.Untrack(ptr)
+
 	err := C._go_git_treewalk(
 		t.cast_ptr,
 		C.GIT_TREEWALK_PRE,
-		unsafe.Pointer(&callback),
+		ptr,
 	)
 
 	if err < 0 {