feat: gix tree entries with rev-spec support.

Previously it wanted a tree-id, now it can derive it itself.

gitoxide-core/src/repository/tree.rs

@@ -2,7 +2,7 @@ use std::{borrow::Cow, io};
 
 use anyhow::bail;
 
-use gix::{prelude::ObjectIdExt, Tree};
+use gix::Tree;
 
 use crate::OutputFormat;
 
@@ -176,13 +176,10 @@ pub fn entries(
 }
 
 fn treeish_to_tree<'repo>(treeish: Option<&str>, repo: &'repo gix::Repository) -> anyhow::Result<Tree<'repo>> {
-    Ok(match treeish {
-        Some(hex) => gix::hash::ObjectId::from_hex(hex.as_bytes())
-            .map(|id| id.attach(repo))?
-            .object()?
-            .try_into_tree()?,
-        None => repo.head()?.peel_to_commit_in_place()?.tree()?,
-    })
+    let spec = treeish
+        .map(|spec| format!("{spec}^{{tree}}"))
+        .unwrap_or_else(|| "@^{tree}".into());
+    Ok(repo.rev_parse_single(spec.as_str())?.object()?.into_tree())
 }
 
 fn format_entry(

src/plumbing/options/mod.rs

@@ -253,15 +253,15 @@ pub mod tree {
             #[clap(long, short = 'e')]
             extended: bool,
 
-            /// The tree to traverse, or the tree at `HEAD` if unspecified.
+            /// The revspec of the tree to traverse, or the tree at `HEAD` if unspecified.
             treeish: Option<String>,
         },
         /// Provide information about a tree.
         Info {
             /// Provide files size as well. This is expensive as the object is decoded entirely.
             #[clap(long, short = 'e')]
             extended: bool,
-            /// The tree to traverse, or the tree at `HEAD` if unspecified.
+            /// The revspec of the tree to traverse, or the tree at `HEAD` if unspecified.
             treeish: Option<String>,
         },
     }