// Copyright 2023 The Jujutsu Authors//// Licensed under the Apache License, Version 2.0 (the "License");// you may not use this file except in compliance with the License.// You may obtain a copy of the License at//// https://www.apache.org/licenses/LICENSE-2.0//// Unless required by applicable law or agreed to in writing, software// distributed under the License is distributed on an "AS IS" BASIS,// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.// See the License for the specific language governing permissions and// limitations under the License. use std::fmt::Debug;use std::io::Write as _; use jj_lib::default_index::AsCompositeIndex as _;use jj_lib::default_index::DefaultReadonlyIndex; use crate::cli_util::CommandHelper;use crate::command_error::internal_error;use crate::command_error::user_error;use crate::command_error::CommandError;use crate::ui::Ui; /// Show commit index stats#[derive(clap::Args, Clone, Debug)]pub struct DebugIndexArgs {} pub fn cmd_debug_index(    ui: &mut Ui,    command: &CommandHelper,    _args: &DebugIndexArgs,) -> Result<(), CommandError> {    // Resolve the operation without loading the repo, so this command won't    // update the index.    let workspace = command.load_workspace()?;    let repo_loader = workspace.repo_loader();    let op = command.resolve_operation(ui, repo_loader)?;    let index_store = repo_loader.index_store();    let index = index_store        .get_index_at_op(&op, repo_loader.store())        .map_err(internal_error)?;    if let Some(default_index) = index.as_any().downcast_ref::<DefaultReadonlyIndex>() {        let stats = default_index.as_composite().stats();        writeln!(ui.stdout(), "Number of commits: {}", stats.num_commits)?;        writeln!(ui.stdout(), "Number of merges: {}", stats.num_merges)?;        writeln!(            ui.stdout(),            "Max generation number: {}",            stats.max_generation_number        )?;        writeln!(ui.stdout(), "Number of heads: {}", stats.num_heads)?;        writeln!(ui.stdout(), "Number of changes: {}", stats.num_changes)?;        writeln!(ui.stdout(), "Stats per level:")?;        for (i, level) in stats.levels.iter().enumerate() {            writeln!(ui.stdout(), "  Level {i}:")?;            writeln!(ui.stdout(), "    Number of commits: {}", level.num_commits)?;            writeln!(ui.stdout(), "    Name: {}", level.name.as_ref().unwrap())?;        }    } else {        return Err(user_error(format!(            "Cannot get stats for indexes of type '{}'",            index_store.name()        )));    }    Ok(())}