Fix null pointer dereference in status.ByIndex (#628)

`git_status_byindex` can return a null pointer if there is no statuses.

1 files changed, 4 insertions, 0 deletions

diff --git a/status.go b/status.go
index e37a96d..3923e1a 100644
--- a/status.go
+++ b/status.go
@@ -6,6 +6,7 @@ package git
 import "C"
 
 import (
+	"errors"
 	"runtime"
 	"unsafe"
 )
@@ -86,6 +87,9 @@ func (statusList *StatusList) ByIndex(index int) (StatusEntry, error) {
 		return StatusEntry{}, ErrInvalid
 	}
 	ptr := C.git_status_byindex(statusList.ptr, C.size_t(index))
+	if ptr == nil {
+		return StatusEntry{}, errors.New("index out of Bounds")
+	}
 	entry := statusEntryFromC(ptr)
 	runtime.KeepAlive(statusList)