fix: Concurrent map read/write in Tree methods

motoki317 · motoki317 · commit a4ab95cd6f7b · 2024-12-05T18:19:44.000+09:00
diff --git a/plumbing/object/tree.go b/plumbing/object/tree.go
@@ -39,7 +39,6 @@ type Tree struct {
 
 	s storer.EncodedObjectStorer
 	m map[string]*TreeEntry
-	t map[string]*Tree // tree path cache
 }
 
 // GetTree gets a tree from an object storer and decodes it.
@@ -128,28 +127,10 @@ func (t *Tree) TreeEntryFile(e *TreeEntry) (*File, error) {
 
 // FindEntry search a TreeEntry in this tree or any subtree.
 func (t *Tree) FindEntry(path string) (*TreeEntry, error) {
-	if t.t == nil {
-		t.t = make(map[string]*Tree)
-	}
-
 	pathParts := strings.Split(path, "/")
 	startingTree := t
 	pathCurrent := ""
 
-	// search for the longest path in the tree path cache
-	for i := len(pathParts) - 1; i > 1; i-- {
-		path := filepath.Join(pathParts[:i]...)
-
-		tree, ok := t.t[path]
-		if ok {
-			startingTree = tree
-			pathParts = pathParts[i:]
-			pathCurrent = path
-
-			break
-		}
-	}
-
 	var tree *Tree
 	var err error
 	for tree = startingTree; len(pathParts) > 1; pathParts = pathParts[1:] {
@@ -158,7 +139,6 @@ func (t *Tree) FindEntry(path string) (*TreeEntry, error) {
 		}
 
 		pathCurrent = filepath.Join(pathCurrent, pathParts[0])
-		t.t[pathCurrent] = tree
 	}
 
 	return tree.entry(pathParts[0])
@@ -182,10 +162,6 @@ func (t *Tree) dir(baseName string) (*Tree, error) {
 }
 
 func (t *Tree) entry(baseName string) (*TreeEntry, error) {
-	if t.m == nil {
-		t.buildMap()
-	}
-
 	entry, ok := t.m[baseName]
 	if !ok {
 		return nil, ErrEntryNotFound
@@ -269,6 +245,8 @@ func (t *Tree) Decode(o plumbing.EncodedObject) (err error) {
 		})
 	}
 
+	t.buildMap()
+
 	return nil
 }
 
diff --git a/plumbing/object/tree_test.go b/plumbing/object/tree_test.go
@@ -264,6 +264,7 @@ func (s *TreeSuite) TestTreeDecodeEncodeIdempotent(c *C) {
 		err = newTree.Decode(obj)
 		c.Assert(err, IsNil)
 		tree.Hash = obj.Hash()
+		tree.buildMap()
 		c.Assert(newTree, DeepEquals, tree)
 	}
 }

Original file line number	Diff line number	Diff line change
`@@ -264,6 +264,7 @@ func (s TreeSuite) TestTreeDecodeEncodeIdempotent(c C) {`
`264`	`264`	`err = newTree.Decode(obj)`
`265`	`265`	`c.Assert(err, IsNil)`
`266`	`266`	`tree.Hash = obj.Hash()`
	`267`	`+ tree.buildMap()`
`267`	`268`	`c.Assert(newTree, DeepEquals, tree)`
`268`	`269`	`}`
`269`	`270`	`}`