failing tests for index rev-parsing (#427)

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

@@ -525,7 +525,15 @@ impl<'repo> delegate::Navigate for Delegate<'repo> {
 
     fn index_lookup(&mut self, _path: &BStr, _stage: u8) -> Option<()> {
         self.unset_disambiguate_call();
-        todo!()
+        match self.repo.index() {
+            Ok(_index) => {
+                todo!("index lookup")
+            }
+            Err(err) => {
+                self.err.push(err.into());
+                None
+            }
+        }
     }
 }
 

git-repository/src/revision/spec/parse/types.rs

@@ -61,6 +61,8 @@ pub struct Options {
 #[derive(Debug, thiserror::Error)]
 #[allow(missing_docs)]
 pub enum Error {
+    #[error(transparent)]
+    Index(#[from] crate::worktree::open_index::Error),
     #[error(transparent)]
     RevWalkIterInit(#[from] crate::reference::iter::init::Error),
     #[error(transparent)]

git-repository/tests/fixtures/make_rev_spec_parse_repos.sh

@@ -343,4 +343,5 @@ git init complex_graph
   baseline ":/!-mes.age" # negated above
   baseline ":/not there" # definitely not in graph
   baseline "@^{/!-B}"    # negation from branch
+  baseline ":file"      # index lookup, default stage 0
 )

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

@@ -7,6 +7,32 @@ pub use util::*;
 
 mod ambiguous;
 mod regex;
+mod index {
+    use crate::revision::spec::from_bytes::{parse_spec, repo};
+    use git_repository::prelude::ObjectIdExt;
+    use git_repository::revision::Spec;
+    use git_testtools::hex_to_id;
+
+    #[test]
+    #[ignore]
+    fn at_default_stage() {
+        let repo = repo("complex_graph").unwrap();
+        assert_eq!(
+            parse_spec(":file", &repo).unwrap(),
+            Spec::from_id(hex_to_id("fe27474251f7f8368742f01fbd3bd5666b630a82").attach(&repo))
+        );
+
+        assert_eq!(
+            parse_spec(":1:file", &repo).unwrap_err().to_string(),
+            "give hint as to where to find the file in the index and if it exists on disk",
+        );
+
+        assert_eq!(
+            parse_spec(":foo", &repo).unwrap_err().to_string(),
+            "does not exist (but use same error message as above, as it's parametric)",
+        );
+    }
+}
 
 #[test]
 fn names_are_made_available_via_references() {