creating new wc commit when @ becomes immuable

cli/src/cli_util.rs

@@ -57,7 +57,7 @@ use jj_lib::revset::{
     RevsetAliasesMap, RevsetExpression, RevsetExtensions, RevsetFilterPredicate, RevsetIteratorExt,
     RevsetModifier, RevsetParseContext, RevsetWorkspaceContext, SymbolResolverExtension,
 };
-use jj_lib::rewrite::restore_tree;
+use jj_lib::rewrite::{merge_commit_trees, restore_tree};
 use jj_lib::settings::{ConfigResultExt as _, UserSettings};
 use jj_lib::signing::SignInitError;
 use jj_lib::str_util::StringPattern;
@@ -1280,7 +1280,6 @@ See https://github.com/martinvonz/jj/blob/main/docs/working-copy.md#stale-workin
         if num_rebased > 0 {
             writeln!(ui.status(), "Rebased {num_rebased} descendant commits")?;
         }
-
         let old_repo = tx.base_repo().clone();
 
         let maybe_old_wc_commit = old_repo
@@ -1304,10 +1303,23 @@ See https://github.com/martinvonz/jj/blob/main/docs/working-copy.md#stale-workin
         }
         self.user_repo = ReadonlyUserRepo::new(tx.commit(description));
         self.report_repo_changes(ui, &old_repo)?;
-
         if self.may_update_working_copy {
             if let Some(new_commit) = &maybe_new_wc_commit {
-                self.update_working_copy(ui, maybe_old_wc_commit.as_ref(), new_commit)?;
+                self.update_working_copy(ui, maybe_old_wc_commit.as_ref(), &new_commit)?;
+                println!("{:?}", new_commit.id());
+                if self.check_rewritable([new_commit.id()]).is_err() {
+                    let settings = self.settings.clone();
+                    let mut tx = self.start_transaction();
+                    let _top_commit = tx
+                        .mut_repo()
+                        .new_commit(
+                            &settings,
+                            vec![new_commit.id().clone()],
+                            new_commit.tree_id().clone(),
+                        )
+                        .write()?;
+                    tx.finish(ui, "added mutable commit to avoid @ immutable.")?;
+                }
             } else {
                 // It seems the workspace was deleted, so we shouldn't try to
                 // update it.