Change ScanIndex to ref & expose git.RefBeforeFirstCommit for clarity

commands/command_fsck.go

@@ -39,7 +39,7 @@ func doFsck() (bool, error) {
 	}
 
 	// TODO(zeroshirts): do we want to look for LFS stuff in past commits?
-	p2, err := lfs.ScanIndex(false)
+	p2, err := lfs.ScanIndex("HEAD")
 	if err != nil {
 		return false, err
 	}

commands/command_status.go

@@ -18,7 +18,12 @@ func statusCommand(cmd *cobra.Command, args []string) {
 	// tolerate errors getting ref so this works before first commit
 	ref, _ := git.CurrentRef()
 
-	stagedPointers, err := lfs.ScanIndex(ref == nil)
+	scanIndexAt := "HEAD"
+	if ref == nil {
+		scanIndexAt = git.RefBeforeFirstCommit
+	}
+
+	stagedPointers, err := lfs.ScanIndex(scanIndexAt)
 	if err != nil {
 		Panic(err, "Could not scan staging for Git LFS objects")
 	}

git/git.go

@@ -30,6 +30,10 @@ const (
 	RefTypeRemoteTag    = RefType(iota)
 	RefTypeHEAD         = RefType(iota) // current checkout
 	RefTypeOther        = RefType(iota) // stash or unknown
+
+	// A ref which can be used as a placeholder for before the first commit
+	// Equivalent to git mktree < /dev/null, useful for diffing before first commit
+	RefBeforeFirstCommit = "4b825dc642cb6eb9a060e54bf8d69288fbee4904"
 )
 
 // A git reference (branch, tag etc)

lfs/scanner.go

@@ -30,9 +30,6 @@ const (
 	// chanBufSize is the size of the channels used to pass data from one
 	// sub-process to another.
 	chanBufSize = 100
-
-	// Equivalent to git mktree < /dev/null, useful for diffing before first commit
-	nullTreeish = "4b825dc642cb6eb9a060e54bf8d69288fbee4904"
 )
 
 var (
@@ -195,8 +192,8 @@ func (m *indexFileMap) Set(sha string, index *indexFile) {
 // ScanIndex returns a slice of WrappedPointer objects for all
 // Git LFS pointers it finds in the index.
 // Reports unique oids once only, not multiple times if >1 file uses the same content
-// isFirstCommit must be true if this repo doesn't have any commits yet
-func ScanIndex(isFirstCommit bool) ([]*WrappedPointer, error) {
+// Ref is the ref at which to scan, which may be "HEAD" if there is at least one commit
+func ScanIndex(ref string) ([]*WrappedPointer, error) {
 	indexMap := &indexFileMap{
 		nameMap: make(map[string]*indexFile, 0),
 		mutex:   &sync.Mutex{},
@@ -207,11 +204,6 @@ func ScanIndex(isFirstCommit bool) ([]*WrappedPointer, error) {
 		tracerx.PerformanceSince("scan-staging", start)
 	}()
 
-	ref := "HEAD"
-	if isFirstCommit {
-		ref = nullTreeish
-	}
-
 	revs, err := revListIndex(ref, false, indexMap)
 	if err != nil {
 		return nil, err