feat: browse GitHub GitLab and Gitea pull requests

tests/repository.rs

@@ -1929,3 +1929,80 @@ fn branch_changes_rejects_missing_and_multiple_merge_bases_without_snapshot_fall
     }
     assert_eq!(disk_state(&root), state);
 }
+
+#[test]
+fn pull_request_refs_fetch_pinned_fork_heads_privately_for_git_and_jj() {
+    let fixture = Fixture::new();
+    let source = fixture.dir("source");
+    init_git(&source);
+    fs::write(source.join("common"), "base\n").unwrap();
+    git(&source, &["add", "."]);
+    git(&source, &["commit", "-m", "base"]);
+    let base = git(&source, &["rev-parse", "HEAD"]);
+    fs::write(source.join("target-only"), "not part of the PR\n").unwrap();
+    git(&source, &["add", "."]);
+    git(&source, &["commit", "-m", "target advanced"]);
+    let target = git(&source, &["rev-parse", "HEAD"]);
+    git(&source, &["checkout", "--detach", &base]);
+    fs::write(source.join("common"), "fork change\n").unwrap();
+    git(&source, &["add", "."]);
+    git(&source, &["commit", "-m", "fork tip"]);
+    let head = git(&source, &["rev-parse", "HEAD"]);
+    git(&source, &["update-ref", "refs/pull/7/head", &head]);
+    for (index, kind) in [RepoKind::Git, RepoKind::Jujutsu, RepoKind::Jujutsu]
+        .into_iter()
+        .enumerate()
+    {
+        let root = fixture.dir(&format!("active-{index}"));
+        if kind == RepoKind::Git {
+            init_git(&root);
+            fs::write(root.join("unrelated"), "local\n").unwrap();
+            git(&root, &["add", "."]);
+            git(&root, &["commit", "-m", "unrelated local"]);
+            git(
+                &root,
+                &["remote", "add", "origin", source.to_str().unwrap()],
+            );
+        } else {
+            init_jj(&root, index == 2);
+            jj(
+                &root,
+                &["git", "remote", "add", "origin", source.to_str().unwrap()],
+            );
+        }
+        fs::write(root.join("unsaved"), "keep\n").unwrap();
+        let state = disk_state(&root);
+        let pinned = |reference: &str, id: &str| Revision {
+            target: RevisionTarget::RemoteCommit {
+                remote: "origin".into(),
+                reference: reference.into(),
+                id: id.into(),
+            },
+            ..revision(id, kind)
+        };
+        let before = pinned("refs/heads/local", &target);
+        let after = pinned("refs/pull/7/head", &head);
+        let mut repository = open(&root);
+        let comparison = repository
+            .compare(70, &before, &after, ComparisonMode::BranchChanges, &[])
+            .unwrap();
+        assert!(comparison.before.ends_with(&base));
+        assert_eq!(comparison.files.len(), 1);
+        assert_eq!(comparison.files[0].path, Path::new("common"));
+        assert!(comparison.editable_paths.is_empty());
+        let file = repository.load_file(70, 0).unwrap();
+        assert_eq!(file.before, ["base"]);
+        assert_eq!(file.after, ["fork change"]);
+        assert_eq!(disk_state(&root), state);
+
+        // A force-push cannot silently replace the immutable tip selected in the picker.
+        let absent = pinned("refs/pull/7/head", &"f".repeat(40));
+        assert!(
+            repository
+                .compare(71, &before, &absent, ComparisonMode::BranchChanges, &[])
+                .unwrap_err()
+                .contains("reopen :pull_requests")
+        );
+        assert_eq!(disk_state(&root), state);
+    }
+}