test_import_refs_reimport.rs: Demonstrate #864's root cause

lib/tests/test_git.rs

@@ -177,7 +177,12 @@ fn test_import_refs_reimport() {
     let commit2 = empty_git_commit(&git_repo, "refs/heads/main", &[&commit1]);
     let commit3 = empty_git_commit(&git_repo, "refs/heads/feature1", &[&commit2]);
     let commit4 = empty_git_commit(&git_repo, "refs/heads/feature2", &[&commit2]);
-    // let commit5 = ... will be introduced in the next commit
+    let commit5 = empty_git_commit(&git_repo, "refs/heads/feature-remote", &[&commit2]);
+    git_ref(
+        &git_repo,
+        "refs/remotes/origin/feature-remote",
+        commit5.id(),
+    );
     let pgp_key_oid = git_repo.blob(b"my PGP key").unwrap();
     git_repo
         .reference("refs/tags/my-gpg-key", pgp_key_oid, false, "")
@@ -191,12 +196,19 @@ fn test_import_refs_reimport() {
     let expected_heads = hashset! {
             jj_id(&commit3),
             jj_id(&commit4),
+            jj_id(&commit5),
     };
     let view = repo.view();
     assert_eq!(*view.heads(), expected_heads);
+    assert!(matches!(view.branches().get("feature-remote"), Some(_)));
 
-    // Delete feature1 and rewrite feature2
+    // Delete feature1 locally
     delete_git_ref(&git_repo, "refs/heads/feature1");
+    // Simulate fetching from a remote where feature-remote branch was deleted to
+    // test #864. This leads to the following import deleting the corresponding
+    // local branch.
+    delete_git_ref(&git_repo, "refs/remotes/origin/feature-remote");
+    // Rewrite feature2
     delete_git_ref(&git_repo, "refs/heads/feature2");
     let commit6 = empty_git_commit(&git_repo, "refs/heads/feature2", &[&commit2]);
 
@@ -219,6 +231,9 @@ fn test_import_refs_reimport() {
 
     let view = repo.view();
     let expected_heads = hashset! {
+            // BUG: commit5 is still listed as a head (#864) even though the
+            // feature-remote branch was deleted as we'll see below.
+            jj_id(&commit5),
             jj_id(&commit6),
             commit7.id().clone(),
     };
@@ -248,10 +263,11 @@ fn test_import_refs_reimport() {
         view.branches().get("feature2"),
         Some(expected_feature2_branch).as_ref()
     );
+    assert_eq!(view.branches().get("feature-remote"), None);
 
     assert!(view.tags().is_empty());
 
-    assert_eq!(view.git_refs().len(), 3);
+    assert_eq!(view.git_refs().len(), 4);
     assert_eq!(
         view.git_refs().get("refs/heads/main"),
         Some(commit2_target).as_ref()
@@ -265,6 +281,13 @@ fn test_import_refs_reimport() {
         view.git_refs().get("refs/heads/feature2"),
         Some(commit6_target).as_ref()
     );
+    let commit5_target = RefTarget::Normal(jj_id(&commit5));
+    assert_eq!(
+        // The git repo ref for the local feature-remote branch continues to exist until
+        // the next `jj git export`
+        view.git_refs().get("refs/heads/feature-remote"),
+        Some(commit5_target).as_ref()
+    );
 }
 
 #[test]