cli: git push: show hint when the only changed bookmarks are deleted ones

Author: winterqt

CHANGELOG.md

@@ -38,6 +38,9 @@ to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 * New `signed` revset function to filter for cryptographically signed commits.
 
+* `jj git push` now shows a hint to use `--deleted` if the only changed bookmarks
+  are deleted ones.
+
 ### Fixed bugs
 
 * Fixed crash on change-delete conflict resolution.

cli/src/commands/git/push.rs

@@ -395,6 +395,25 @@ pub fn cmd_git_push(
         );
     }
     if bookmark_updates.is_empty() {
+        let deleted_bookmarks = tx
+            .repo()
+            .view()
+            .local_remote_bookmarks(remote)
+            .filter(|(_, targets)| {
+                !targets.local_target.is_present()
+                    && matches!(classify_bookmark_push_action(*targets),
+                        BookmarkPushAction::Update(update) if update.new_target.is_none())
+            })
+            .count();
+
+        if deleted_bookmarks > 0 {
+            writeln!(
+                ui.hint_default(),
+                "You can push {deleted_bookmarks} deleted bookmark{s} with `--deleted`",
+                s = if deleted_bookmarks > 1 { "s" } else { "" }
+            )?;
+        }
+
         writeln!(ui.status(), "Nothing changed.")?;
         return Ok(());
     }

cli/tests/test_git_push.rs

@@ -1961,6 +1961,14 @@ fn test_git_push_deleted(subprocess: bool) {
     work_dir
         .run_jj(["bookmark", "delete", "bookmark1"])
         .success();
+    let output = work_dir.run_jj(["git", "push"]);
+    insta::assert_snapshot!(output, @r"
+    ------- stderr -------
+    Warning: No bookmarks found in the default push revset: remote_bookmarks(remote=origin)..@
+    Hint: You can push 1 deleted bookmark with `--deleted`
+    Nothing changed.
+    [EOF]
+    ");
     let output = work_dir.run_jj(["git", "push", "--deleted"]);
     insta::allow_duplicates! {
     insta::assert_snapshot!(output, @r"