GitoxideLabs · Sebastian Thiel (Byron) · May 18, 2026
diff --git a/gix/src/revision/spec/parse/delegate/revision.rs b/gix/src/revision/spec/parse/delegate/revision.rs
@@ -207,7 +207,16 @@ impl delegate::Revision for Delegate<'_> {
                         self.refs[self.idx] = Some(r.detach());
                         id
                     }
-                    Err(_) => id,
+                    Err(_) => match ObjectId::from_hex(ref_name.as_ref()) {
+                        Ok(id) if id.kind() == self.repo.object_hash() => id,
+                        _ => {
+                            return Err(message!(
+                                "Previous checkout '{name}' does not resolve to an existing revision",
+                                name = ref_name.as_bstr()
+                            )
+                            .raise_erased());
+                        }
+                    },
                 };
                 let objs = self.objs[self.idx].get_or_insert_with(Vec::new);
                 if !objs.contains(&id) {

diff --git a/gix/tests/fixtures/generated-archives/make_rev_spec_parse_repos.tar b/gix/tests/fixtures/generated-archives/make_rev_spec_parse_repos.tar
diff --git a/gix/tests/fixtures/make_rev_spec_parse_repos.sh b/gix/tests/fixtures/make_rev_spec_parse_repos.sh
@@ -450,6 +450,37 @@ EOF
   baseline @...@
 )
 
+git init deleted_prior_checkout
+(
+  cd deleted_prior_checkout
+  tick
+
+  git commit --allow-empty -m c1
+  git checkout -b prev-target
+  git checkout main
+  git branch -d prev-target
+
+  # `@{-1}` replays the previous checkout name through regular revision
+  # parsing. Once that branch is deleted, Git rejects it even though HEAD's
+  # reflog still contains the previous object id.
+  baseline "@{-1}"
+)
+
+git init deleted_prior_checkout_named_like_object
+(
+  cd deleted_prior_checkout_named_like_object
+  tick
+
+  git commit --allow-empty -m c1
+  git checkout -b 0123456789012345678901234567890123456789
+  git checkout main
+  git branch -d 0123456789012345678901234567890123456789
+
+  # Git interprets a previous checkout name that is a full object id as
+  # that object id, even when no such object exists in the database.
+  baseline "@{-1}"
+)
+
 git init new
 (cd new
   baseline '@{1}'

diff --git a/gix/tests/gix/revision/spec/from_bytes/reflog.rs b/gix/tests/gix/revision/spec/from_bytes/reflog.rs
@@ -27,6 +27,30 @@ fn nth_prior_checkout() {
     );
 }
 
+#[test]
+fn nth_prior_checkout_to_deleted_branch_fails_like_git() -> crate::Result {
+    let repo = repo("deleted_prior_checkout")?;
+    let err = parse_spec("@{-1}", &repo).expect_err("deleted prior checkout branch must not resolve by object id");
+    assert!(
+        err.probable_cause()
+            .to_string()
+            .contains("Previous checkout 'prev-target' does not resolve"),
+        "error should explain that the reflog name no longer resolves"
+    );
+    Ok(())
+}
+
+#[test]
+fn nth_prior_checkout_to_deleted_branch_named_like_object_matches_git() -> crate::Result {
+    let repo = repo("deleted_prior_checkout_named_like_object")?;
+    assert_eq!(
+        parse_spec("@{-1}", &repo)?,
+        Spec::from_id(hex_to_id_sha1_only("0123456789012345678901234567890123456789").attach(&repo)),
+        "full object ids are accepted as previous checkout names, even without matching objects"
+    );
+    Ok(())
+}
+
 #[test]
 fn by_index_unborn_head() {
     let repo = &repo("new").unwrap();