prepare test for handling the 'unborn' lsrefs extension (#450)

git-repository/src/clone/fetch/util.rs

@@ -59,7 +59,7 @@ pub fn update_head(
         None => return Ok(()),
     };
 
-    let name: git_ref::FullName = "HEAD".try_into().expect("valid");
+    let head: git_ref::FullName = "HEAD".try_into().expect("valid");
     let reflog_message = || LogChange {
         mode: RefLog::AndReference,
         force_create_reflog: false,
@@ -98,7 +98,7 @@ pub fn update_head(
                                 expected: PreviousValue::Any,
                                 new: Target::Symbolic(referent),
                             },
-                            name: name.clone(),
+                            name: head.clone(),
                             deref: false,
                         },
                     ],
@@ -116,7 +116,7 @@ pub fn update_head(
                     expected: PreviousValue::Any,
                     new: Target::Peeled(head_peeled_id.to_owned()),
                 },
-                name,
+                name: head,
                 deref: false,
             })?;
         }
@@ -127,7 +127,7 @@ pub fn update_head(
                     expected: PreviousValue::Any,
                     new: Target::Peeled(head_peeled_id.to_owned()),
                 },
-                name,
+                name: head,
                 deref: false,
             })?;
         }

git-repository/src/remote/fetch.rs

@@ -53,6 +53,7 @@ impl Source {
         match self {
             Source::ObjectId(_) => None,
             Source::Ref(r) => match r {
+                git_protocol::fetch::Ref::Unborn { target: _ } => Some("HEAD".into()),
                 git_protocol::fetch::Ref::Symbolic { full_ref_name, .. }
                 | git_protocol::fetch::Ref::Direct { full_ref_name, .. }
                 | git_protocol::fetch::Ref::Peeled { full_ref_name, .. } => Some(full_ref_name.as_ref()),

git-repository/tests/clone/mod.rs

@@ -193,19 +193,41 @@ mod blocking_io {
     }
 
     #[test]
+    #[ignore]
     fn fetch_and_checkout_empty_remote_repo() -> crate::Result {
         let tmp = git_testtools::tempfile::TempDir::new()?;
         let mut prepare = git::prepare_clone(
             git_testtools::scripted_fixture_repo_read_only("make_empty_repo.sh")?,
             tmp.path(),
         )?;
-        let (mut checkout, _out) = prepare
+        let (mut checkout, out) = prepare
             .fetch_then_checkout(git::progress::Discard, &std::sync::atomic::AtomicBool::default())
             .unwrap();
         let (repo, _) = checkout.main_worktree(git::progress::Discard, &std::sync::atomic::AtomicBool::default())?;
 
         assert!(!repo.index_path().is_file(), "newly initialized repos have no index");
         assert!(repo.head()?.is_unborn());
+        if out
+            .ref_map
+            .handshake
+            .capabilities
+            .capability("ls-refs")
+            .expect("has ls-refs")
+            .supports("unborn")
+            == Some(true)
+        {
+            assert_eq!(
+                repo.head()?.referent_name().expect("present").as_bstr(),
+                "refs/heads/special",
+                "we pick up the name as present on the server, not the one we default to"
+            );
+        } else {
+            assert_eq!(
+                repo.head()?.referent_name().expect("present").as_bstr(),
+                "refs/heads/main",
+                "we simply keep our own post-init HEAD which defaults to the branch name we configured locally"
+            );
+        }
 
         Ok(())
     }

git-repository/tests/fixtures/make_empty_repo.sh

@@ -1,4 +1,4 @@
 #!/bin/bash
 set -eu -o pipefail
 
-git init -q
+git -c init.defaultBranch=special init -q