feat: add conversion from tree::Entry to EntryRef with From

Author: Byron

gix-object/src/object/convert.rs

@@ -78,6 +78,17 @@ impl From<tree::EntryRef<'_>> for tree::Entry {
     }
 }
 
+impl<'a> From<&'a tree::Entry> for tree::EntryRef<'a> {
+    fn from(other: &'a tree::Entry) -> tree::EntryRef<'a> {
+        let tree::Entry { mode, filename, oid } = other;
+        tree::EntryRef {
+            mode: *mode,
+            filename: filename.as_ref(),
+            oid: &oid,
+        }
+    }
+}
+
 impl From<ObjectRef<'_>> for Object {
     fn from(v: ObjectRef<'_>) -> Self {
         match v {

gix-object/tests/object/tree/editor.rs

@@ -619,6 +619,7 @@ fn from_existing_add() -> crate::Result {
     let root_tree = find_tree(&odb, root_tree_id)?;
     odb.access_count_and_clear();
     let mut edit = gix_object::tree::Editor::new(root_tree.clone(), &odb, gix_hash::Kind::Sha1);
+    assert!(edit.get(&["bin"]).is_some(), "the root is immediately available");
 
     let actual = edit.write(&mut write).expect("no changes are fine");
     assert_eq!(actual, root_tree_id, "it rewrites the same tree");