support for @: == @^{tree} in rev-parsing

Author: Byron

git-repository/src/revision/spec/parse/delegate/navigate.rs

@@ -120,6 +120,9 @@ impl<'repo> delegate::Navigate for Delegate<'repo> {
             PeelTo::Path(path) => {
                 let lookup_path = |obj: &ObjectId| {
                     let tree_id = peel(repo, obj, git_object::Kind::Tree)?;
+                    if path.is_empty() {
+                        return Ok(tree_id);
+                    }
                     let tree = repo.find_object(tree_id)?.into_tree();
                     let entry = tree
                         .lookup_path(git_path::from_bstr(path).components().map(|c| {

git-repository/tests/fixtures/generated-archives/make_rev_spec_parse_repos.tar.xz

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:59a25603e3f0bf76e32f3a947b4e275afdfc1e2a0b7ab0e159cc5cc0119f9556
-size 28084
+oid sha256:d96a9986f29cdc7d4a3aacae4718871d2b6079e8634ea817b8c63b75665eb32f
+size 28172

git-repository/tests/fixtures/make_rev_spec_parse_repos.sh

@@ -386,4 +386,7 @@ git init complex_graph
   baseline "@^{}"
   baseline "main^{}"
   baseline "b-tag^{}"
+
+  baseline "@^{tree}"
+  baseline "@:"
 )

git-repository/tests/revision/spec/from_bytes/mod.rs

@@ -10,25 +10,7 @@ mod regex;
 mod reflog;
 mod traverse;
 
-mod peel {
-    use git_repository::{prelude::ObjectIdExt, revision::Spec};
-    use git_testtools::hex_to_id;
-
-    use crate::revision::spec::from_bytes::{parse_spec, repo};
-
-    #[test]
-    fn peel_to_object() {
-        let repo = &repo("complex_graph").unwrap();
-
-        let expected = Spec::from_id(hex_to_id("55e825ebe8fd2ff78cad3826afb696b96b576a7e").attach(repo));
-        assert_eq!(parse_spec("@^{}", repo).unwrap(), expected);
-        assert_eq!(parse_spec("main^{}", repo).unwrap(), expected);
-        assert_eq!(
-            parse_spec("b-tag^{}", repo).unwrap(),
-            Spec::from_id(hex_to_id("5b3f9e24965d0b28780b7ce5daf2b5b7f7e0459f").attach(repo))
-        );
-    }
-}
+mod peel;
 
 mod sibling_branch {
     use git_repository::revision::spec::parse::Error;

git-repository/tests/revision/spec/from_bytes/peel.rs

@@ -0,0 +1,23 @@
+use git_repository::{prelude::ObjectIdExt, revision::Spec};
+use git_testtools::hex_to_id;
+
+use crate::revision::spec::from_bytes::{parse_spec, repo};
+
+#[test]
+fn peel_to_object() {
+    let repo = &repo("complex_graph").unwrap();
+
+    let expected = Spec::from_id(hex_to_id("55e825ebe8fd2ff78cad3826afb696b96b576a7e").attach(repo));
+    assert_eq!(parse_spec("@^{}", repo).unwrap(), expected);
+    assert_eq!(parse_spec("main^{}", repo).unwrap(), expected);
+    assert_eq!(
+        parse_spec("b-tag^{}", repo).unwrap(),
+        Spec::from_id(hex_to_id("5b3f9e24965d0b28780b7ce5daf2b5b7f7e0459f").attach(repo))
+    );
+}
+
+#[test]
+fn trailing_colon_is_equivalent_to_peel_to_tree() {
+    let repo = &repo("complex_graph").unwrap();
+    assert_eq!(parse_spec("@^{tree}", repo).unwrap(), parse_spec("@:", repo).unwrap());
+}