// Copyright 2020 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::io::{self, Read, Write}; use jj_lib::object_id::ObjectId;use tracing::instrument; use crate::cli_util::{CommandHelper, RevisionArg};use crate::command_error::CommandError;use crate::description_util::{    description_template_for_describe, edit_description, join_message_paragraphs,};use crate::ui::Ui; /// Update the change description or other metadata////// Starts an editor to let you edit the description of a change. The editor/// will be $EDITOR, or `pico` if that's not defined (`Notepad` on Windows).#[derive(clap::Args, Clone, Debug)]#[command(visible_aliases = &["desc"])]pub(crate) struct DescribeArgs {    /// The revision whose description to edit    #[arg(default_value = "@")]    revision: RevisionArg,    /// Ignored (but lets you pass `-r` for consistency with other commands)    #[arg(short = 'r', hide = true)]    unused_revision: bool,    /// The change description to use (don't open editor)    #[arg(long = "message", short, value_name = "MESSAGE")]    message_paragraphs: Vec<String>,    /// Read the change description from stdin    #[arg(long)]    stdin: bool,    /// Don't open an editor    ///    /// This is mainly useful in combination with e.g. `--reset-author`.    #[arg(long)]    no_edit: bool,    /// Reset the author to the configured user    ///    /// This resets the author name, email, and timestamp.    ///    /// You can use it in combination with the JJ_USER and JJ_EMAIL    /// environment variables to set a different author:    ///    /// $ JJ_USER='Foo Bar' JJ_EMAIL=foo@bar.com jj describe --reset-author    #[arg(long)]    reset_author: bool,} #[instrument(skip_all)]pub(crate) fn cmd_describe(    ui: &mut Ui,    command: &CommandHelper,    args: &DescribeArgs,) -> Result<(), CommandError> {    let mut workspace_command = command.workspace_helper(ui)?;    let commit = workspace_command.resolve_single_rev(&args.revision)?;    workspace_command.check_rewritable([&commit])?;    let description = if args.stdin {        let mut buffer = String::new();        io::stdin().read_to_string(&mut buffer).unwrap();        buffer    } else if !args.message_paragraphs.is_empty() {        join_message_paragraphs(&args.message_paragraphs)    } else if args.no_edit {        commit.description().to_owned()    } else {        let template =            description_template_for_describe(ui, command.settings(), &workspace_command, &commit)?;        edit_description(workspace_command.repo(), &template, command.settings())?    };    if description == *commit.description() && !args.reset_author {        writeln!(ui.stderr(), "Nothing changed.")?;    } else {        let mut tx = workspace_command.start_transaction();        let mut commit_builder = tx            .mut_repo()            .rewrite_commit(command.settings(), &commit)            .set_description(description);        if args.reset_author {            let new_author = commit_builder.committer().clone();            commit_builder = commit_builder.set_author(new_author);        }        commit_builder.write()?;        tx.finish(ui, format!("describe commit {}", commit.id().hex()))?;    }    Ok(())}