WIP: sort entries by full path name before compare

check.go

@@ -5,18 +5,18 @@ package mtree
 // If keywords is nil, the check all present in the DirectoryHierarchy
 //
 // This is equivalent to creating a new DirectoryHierarchy with Walk(root, nil,
-// keywords, fs) and then doing a Compare(dh, newDh, keywords).
+// keywords, fs) and then doing a Compare(dh, curDh, keywords).
 func Check(root string, dh *DirectoryHierarchy, keywords []Keyword, fs FsEval) ([]InodeDelta, error) {
 	if keywords == nil {
 		keywords = dh.UsedKeywords()
 	}
 
-	newDh, err := Walk(root, nil, keywords, fs)
+	curDh, err := Walk(root, nil, keywords, fs)
 	if err != nil {
 		return nil, err
 	}
 
-	return Compare(dh, newDh, keywords)
+	return Compare(dh, curDh, keywords)
 }
 
 // TarCheck is the tar equivalent of checking a file hierarchy spec against a

compare.go

@@ -3,6 +3,7 @@ package mtree
 import (
 	"encoding/json"
 	"fmt"
+	"sort"
 	"strconv"
 )
 
@@ -325,13 +326,17 @@ func compareEntry(oldEntry, newEntry Entry) ([]KeyDelta, error) {
 // missing entries and the like). A missing or extra key is treated as a
 // Modified type.
 //
-// If oldDh or newDh are empty, we assume they are a hierarchy that is
+// If thisDh or thatDh are empty, we assume they are a hierarchy that is
 // completely empty. This is purely for helping callers create synthetic
 // InodeDeltas.
 //
+// Comparing this directory hierarchy to that directory hierarchy is that
+// sometimes it has few than all files, or may not have directories, etc.,
+// so lack of presence of entries in thisDh may not be reportable.
+//
 // NB: The order of the parameters matters (old, new) because Extra and
 //     Missing are considered as different discrepancy types.
-func Compare(oldDh, newDh *DirectoryHierarchy, keys []Keyword) ([]InodeDelta, error) {
+func Compare(thisDh, thatDh *DirectoryHierarchy, keys []Keyword) ([]InodeDelta, error) {
 	// Represents the new and old states for an entry.
 	type stateT struct {
 		Old *Entry
@@ -343,8 +348,9 @@ func Compare(oldDh, newDh *DirectoryHierarchy, keys []Keyword) ([]InodeDelta, er
 	diffs := map[string]*stateT{}
 
 	// First, iterate over the old hierarchy. If nil, pretend it's empty.
-	if oldDh != nil {
+	if thisDh != nil {
-		for _, e := range oldDh.Entries {
+		sort.Sort(byName(thisDh.Entries))
+		for _, e := range thisDh.Entries {
 			if e.Type == RelativeType || e.Type == FullType {
 				path, err := e.Path()
 				if err != nil {
@@ -365,8 +371,9 @@ func Compare(oldDh, newDh *DirectoryHierarchy, keys []Keyword) ([]InodeDelta, er
 	}
 
 	// Then, iterate over the new hierarchy. If nil, pretend it's empty.
-	if newDh != nil {
+	if thatDh != nil {
-		for _, e := range newDh.Entries {
+		sort.Sort(byName(thatDh.Entries))
+		for _, e := range thatDh.Entries {
 			if e.Type == RelativeType || e.Type == FullType {
 				path, err := e.Path()
 				if err != nil {

entry.go

@@ -14,6 +14,33 @@ func (bp byPos) Len() int           { return len(bp) }
 func (bp byPos) Less(i, j int) bool { return bp[i].Pos < bp[j].Pos }
 func (bp byPos) Swap(i, j int)      { bp[i], bp[j] = bp[j], bp[i] }
 
+type byName []Entry
+
+func (bp byName) Len() int { return len(bp) }
+func (bp byName) Less(i, j int) bool {
+	var iParent string
+	var jParent string
+	var err error
+	if bp[i].Parent != nil {
+		iParent, err = bp[i].Parent.Path()
+		if err != nil {
+			return false
+		}
+	}
+	iName := filepath.Clean(filepath.Join(iParent, bp[i].Name))
+
+	if bp[j].Parent != nil {
+		jParent, err = bp[j].Parent.Path()
+		if err != nil {
+			return false
+		}
+	}
+	jName := filepath.Clean(filepath.Join(jParent, bp[j].Name))
+
+	return iName < jName
+}
+func (bp byName) Swap(i, j int) { bp[i], bp[j] = bp[j], bp[i] }
+
 // Entry is each component of content in the mtree spec file
 type Entry struct {
 	Parent     *Entry   // up