Fix out-of-bounds access possibility in safe code.

With the `id` and `tree` fields of `NodeRef` and `NodeMut` being public,
it was possible to assign to them.
For example, it was possible to build a `NodeMut`
for large ID/index in a small tree/Vec.
Since some APIs use unchecked indexing, this would let users of this library
cause out-of-bounds access in a `Vec` without writing `unsafe` code themselves.

This commit fixes that issue by making the fields private
and instead providing read-only access via accessor methods.
Now the fields can only be set by the `ego-tree` crate,
which can make sure to only ever use an ID that is in-bounds for a given tree.

Author: SimonSapin

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ego-tree"
-version = "0.5.1"
+version = "0.6.0"
 description = "Vec-backed ID-tree"
 keywords = ["tree", "vec", "id", "index"]
 authors = ["Curtis McEnroe <programble@gmail.com>"]

src/lib.rs

@@ -76,12 +76,10 @@ impl<T> Node<T> {
 #[derive(Debug)]
 pub struct NodeRef<'a, T: 'a> {
     /// Node ID.
-    #[deprecated(since = "0.5.1", note = "use the id() method instead and upgrade to 0.6")]
-    pub id: NodeId,
+    id: NodeId,
 
     /// Tree containing the node.
-    #[deprecated(since = "0.5.1", note = "use the tree() method instead and upgrade to 0.6")]
-    pub tree: &'a Tree<T>,
+    tree: &'a Tree<T>,
 
     node: &'a Node<T>,
 }
@@ -90,12 +88,10 @@ pub struct NodeRef<'a, T: 'a> {
 #[derive(Debug)]
 pub struct NodeMut<'a, T: 'a> {
     /// Node ID.
-    #[deprecated(since = "0.5.1", note = "use the id() method instead and upgrade to 0.6")]
-    pub id: NodeId,
+    id: NodeId,
 
     /// Tree containing the node.
-    #[deprecated(since = "0.5.1", note = "use the tree() method instead and upgrade to 0.6")]
-    pub tree: &'a mut Tree<T>,
+    tree: &'a mut Tree<T>,
 }
 
 // Trait implementations regardless of T.
@@ -107,15 +103,13 @@ impl<'a, T: 'a> Clone for NodeRef<'a, T> {
 
 impl<'a, T: 'a> Eq for NodeRef<'a, T> { }
 impl<'a, T: 'a> PartialEq for NodeRef<'a, T> {
-    #[allow(deprecated)]
     fn eq(&self, other: &Self) -> bool {
         self.id == other.id
             && self.tree as *const _ == other.tree as *const _
             && self.node as *const _ == other.node as *const _
     }
 }
 
-#[allow(deprecated)]
 impl<T> Tree<T> {
     /// Creates a tree with a root node.
     pub fn new(root: T) -> Self {
@@ -176,7 +170,6 @@ impl<T> Tree<T> {
     }
 }
 
-#[allow(deprecated)]
 impl<'a, T: 'a> NodeRef<'a, T> {
     /// Returns the ID of this node.
     pub fn id(&self) -> NodeId {
@@ -229,7 +222,6 @@ impl<'a, T: 'a> NodeRef<'a, T> {
     }
 }
 
-#[allow(deprecated)]
 impl<'a, T: 'a> NodeMut<'a, T> {
     /// Returns the ID of this node.
     pub fn id(&self) -> NodeId {
@@ -548,7 +540,6 @@ impl<'a, T: 'a> NodeMut<'a, T> {
     }
 }
 
-#[allow(deprecated)]
 impl<'a, T: 'a> From<NodeMut<'a, T>> for NodeRef<'a, T> {
     fn from(node: NodeMut<'a, T>) -> Self {
         unsafe { node.tree.get_unchecked(node.id) }