upgrade clap to 4.0

Cargo.lock

@@ -53,17 +53,6 @@ dependencies = [
  "wait-timeout",
 ]
 
-[[package]]
-name = "atty"
-version = "0.2.14"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d9b39be18770d11421cdb1b9947a45dd3f37e93092cbf377614828a319d5fee8"
-dependencies = [
- "hermit-abi 0.1.19",
- "libc",
- "winapi",
-]
-
 [[package]]
 name = "autocfg"
 version = "1.1.0"
@@ -176,34 +165,33 @@ dependencies = [
 
 [[package]]
 name = "clap"
-version = "3.2.23"
+version = "4.0.29"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "71655c45cb9845d3270c9d6df84ebe72b4dad3c2ba3f7023ad47c144e4e473a5"
+checksum = "4d63b9e9c07271b9957ad22c173bae2a4d9a81127680962039296abcd2f8251d"
 dependencies = [
- "atty",
  "bitflags",
  "clap_lex",
- "indexmap",
+ "is-terminal",
  "once_cell",
  "strsim",
  "termcolor",
- "textwrap",
+ "terminal_size",
 ]
 
 [[package]]
 name = "clap_complete"
-version = "3.2.5"
+version = "4.0.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3f7a2e0a962c45ce25afce14220bc24f9dade0a1787f185cecf96bfba7847cd8"
+checksum = "b7b3c9eae0de7bf8e3f904a5e40612b21fb2e2e566456d177809a48b892d24da"
 dependencies = [
  "clap",
 ]
 
 [[package]]
 name = "clap_lex"
-version = "0.2.4"
+version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2850f2f5a82cbf437dd5af4d49848fbdfc27c157c3d010345776f952765261c5"
+checksum = "0d4198f73e42b4936b35b5bb248d81d2b595ecb170da0bac7655c54eedfa8da8"
 dependencies = [
  "os_str_bytes",
 ]
@@ -1654,18 +1642,22 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "terminal_size"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cb20089a8ba2b69debd491f8d2d023761cbf196e999218c591fa1e7e15a21907"
+dependencies = [
+ "rustix",
+ "windows-sys",
+]
+
 [[package]]
 name = "termtree"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "95059e91184749cb66be6dc994f67f182b6d897cb3df74a5bf66b5e709295fd8"
 
-[[package]]
-name = "textwrap"
-version = "0.16.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "222a222a5bfe1bba4a77b45ec488a741b3cb8872e5e499451fd7d0129c9c7c3d"
-
 [[package]]
 name = "thiserror"
 version = "1.0.37"

Cargo.toml

@@ -19,8 +19,8 @@ rust-version = "1.60"
 [dependencies]
 anyhow = "1.0.28"
 chrono = "0.4"
-clap = { version = "3.0", features = ["cargo"] }
+clap = { version = "4.0.29", features = ["cargo", "wrap_help"] }
-clap_complete = "3.0"
+clap_complete = "4.0.6"
 once_cell = "1"
 env_logger = "0.10.0"
 handlebars = "4.0"

examples/nop-preprocessor.rs

@@ -1,5 +1,5 @@
 use crate::nop_lib::Nop;
-use clap::{App, Arg, ArgMatches};
+use clap::{Arg, ArgMatches, Command};
 use mdbook::book::Book;
 use mdbook::errors::Error;
 use mdbook::preprocess::{CmdPreprocessor, Preprocessor, PreprocessorContext};
@@ -7,11 +7,11 @@ use semver::{Version, VersionReq};
 use std::io;
 use std::process;
 
-pub fn make_app() -> App<'static> {
+pub fn make_app() -> Command {
-    App::new("nop-preprocessor")
+    Command::new("nop-preprocessor")
         .about("A mdbook preprocessor which does precisely nothing")
         .subcommand(
-            App::new("supports")
+            Command::new("supports")
                 .arg(Arg::new("renderer").required(true))
                 .about("Check whether a renderer is supported by this preprocessor"),
         )
@@ -54,7 +54,9 @@ fn handle_preprocessing(pre: &dyn Preprocessor) -> Result<(), Error> {
 }
 
 fn handle_supports(pre: &dyn Preprocessor, sub_args: &ArgMatches) -> ! {
-    let renderer = sub_args.value_of("renderer").expect("Required argument");
+    let renderer = sub_args
+        .get_one::<String>("renderer")
+        .expect("Required argument");
     let supported = pre.supports_renderer(renderer);
 
     // Signal whether the renderer is supported by exiting with 1 or 0.

src/book/mod.rs

@@ -313,6 +313,7 @@ impl MDBook {
                     }
                 }
 
+                debug!("running {:?}", cmd);
                 let output = cmd.output()?;
 
                 if !output.status.success() {

src/cmd/build.rs

@@ -1,28 +1,16 @@
+use super::command_prelude::*;
 use crate::{get_book_dir, open};
-use clap::{arg, App, Arg, ArgMatches};
 use mdbook::errors::Result;
 use mdbook::MDBook;
+use std::path::PathBuf;
 
 // Create clap subcommand arguments
-pub fn make_subcommand<'help>() -> App<'help> {
+pub fn make_subcommand() -> Command {
-    App::new("build")
+    Command::new("build")
         .about("Builds a book from its markdown files")
-        .arg(
+        .arg_dest_dir()
-            Arg::new("dest-dir")
+        .arg_root_dir()
-                .short('d')
+        .arg_open()
-                .long("dest-dir")
-                .value_name("dest-dir")
-                .help(
-                    "Output directory for the book{n}\
-                    Relative paths are interpreted relative to the book's root directory.{n}\
-                    If omitted, mdBook uses build.build-dir from book.toml or defaults to `./book`.",
-                ),
-        )
-        .arg(arg!([dir]
-            "Root directory for the book{n}\
-            (Defaults to the Current Directory when omitted)"
-        ))
-        .arg(arg!(-o --open "Opens the compiled book in a web browser"))
 }
 
 // Build command implementation
@@ -30,13 +18,13 @@ pub fn execute(args: &ArgMatches) -> Result<()> {
     let book_dir = get_book_dir(args);
     let mut book = MDBook::load(&book_dir)?;
 
-    if let Some(dest_dir) = args.value_of("dest-dir") {
+    if let Some(dest_dir) = args.get_one::<PathBuf>("dest-dir") {
         book.config.build.build_dir = dest_dir.into();
     }
 
     book.build()?;
 
-    if args.is_present("open") {
+    if args.get_flag("open") {
         // FIXME: What's the right behaviour if we don't use the HTML renderer?
         let path = book.build_dir_for("html").join("index.html");
         if !path.exists() {

src/cmd/clean.rs

@@ -1,28 +1,16 @@
+use super::command_prelude::*;
 use crate::get_book_dir;
 use anyhow::Context;
-use clap::{arg, App, Arg, ArgMatches};
 use mdbook::MDBook;
 use std::fs;
+use std::path::PathBuf;
 
 // Create clap subcommand arguments
-pub fn make_subcommand<'help>() -> App<'help> {
+pub fn make_subcommand() -> Command {
-    App::new("clean")
+    Command::new("clean")
         .about("Deletes a built book")
-        .arg(
+        .arg_dest_dir()
-            Arg::new("dest-dir")
+        .arg_root_dir()
-                .short('d')
-                .long("dest-dir")
-                .value_name("dest-dir")
-                .help(
-                    "Output directory for the book{n}\
-                    Relative paths are interpreted relative to the book's root directory.{n}\
-                    If omitted, mdBook uses build.build-dir from book.toml or defaults to `./book`.",
-                ),
-        )
-        .arg(arg!([dir]
-            "Root directory for the book{n}\
-            (Defaults to the Current Directory when omitted)"
-        ))
 }
 
 // Clean command implementation
@@ -30,7 +18,7 @@ pub fn execute(args: &ArgMatches) -> mdbook::errors::Result<()> {
     let book_dir = get_book_dir(args);
     let book = MDBook::load(&book_dir)?;
 
-    let dir_to_remove = match args.value_of("dest-dir") {
+    let dir_to_remove = match args.get_one::<PathBuf>("dest-dir") {
         Some(dest_dir) => dest_dir.into(),
         None => book.root.join(&book.config.build.build_dir),
     };

src/cmd/command_prelude.rs

@@ -0,0 +1,45 @@
+//! Helpers for building the command-line arguments for commands.
+
+pub use clap::{arg, Arg, ArgMatches, Command};
+use std::path::PathBuf;
+
+pub trait CommandExt: Sized {
+    fn _arg(self, arg: Arg) -> Self;
+
+    fn arg_dest_dir(self) -> Self {
+        self._arg(
+            Arg::new("dest-dir")
+                .short('d')
+                .long("dest-dir")
+                .value_name("dest-dir")
+                .value_parser(clap::value_parser!(PathBuf))
+                .help(
+                    "Output directory for the book\n\
+                    Relative paths are interpreted relative to the book's root directory.\n\
+                    If omitted, mdBook uses build.build-dir from book.toml \
+                    or defaults to `./book`.",
+                ),
+        )
+    }
+
+    fn arg_root_dir(self) -> Self {
+        self._arg(
+            Arg::new("dir")
+                .help(
+                    "Root directory for the book\n\
+                    (Defaults to the current directory when omitted)",
+                )
+                .value_parser(clap::value_parser!(PathBuf)),
+        )
+    }
+
+    fn arg_open(self) -> Self {
+        self._arg(arg!(-o --open "Opens the compiled book in a web browser"))
+    }
+}
+
+impl CommandExt for Command {
+    fn _arg(self, arg: Arg) -> Self {
+        self.arg(arg)
+    }
+}

src/cmd/init.rs

@@ -1,5 +1,5 @@
 use crate::get_book_dir;
-use clap::{arg, App, Arg, ArgMatches};
+use clap::{arg, ArgMatches, Command as ClapCommand};
 use mdbook::config;
 use mdbook::errors::Result;
 use mdbook::MDBook;
@@ -8,30 +8,22 @@ use std::io::Write;
 use std::process::Command;
 
 // Create clap subcommand arguments
-pub fn make_subcommand<'help>() -> App<'help> {
+pub fn make_subcommand() -> ClapCommand {
-    App::new("init")
+    ClapCommand::new("init")
         .about("Creates the boilerplate structure and files for a new book")
-        // the {n} denotes a newline which will properly aligned in all help messages
+        .arg(
-        .arg(arg!([dir]
+            arg!([dir]
-            "Directory to create the book in{n}\
+                "Directory to create the book in\n\
-            (Defaults to the Current Directory when omitted)"
+                (Defaults to the current directory when omitted)"
-        ))
+            )
+            .value_parser(clap::value_parser!(std::path::PathBuf)),
+        )
         .arg(arg!(--theme "Copies the default theme into your source folder"))
         .arg(arg!(--force "Skips confirmation prompts"))
+        .arg(arg!(--title <title> "Sets the book title"))
         .arg(
-            Arg::new("title")
+            arg!(--ignore <ignore> "Creates a VCS ignore file (i.e. .gitignore)")
-                .long("title")
+                .value_parser(["none", "git"]),
-                .takes_value(true)
-                .help("Sets the book title")
-                .required(false),
-        )
-        .arg(
-            Arg::new("ignore")
-                .long("ignore")
-                .takes_value(true)
-                .possible_values(&["none", "git"])
-                .help("Creates a VCS ignore file (i.e. .gitignore)")
-                .required(false),
         )
 }
 
@@ -41,12 +33,12 @@ pub fn execute(args: &ArgMatches) -> Result<()> {
     let mut builder = MDBook::init(&book_dir);
     let mut config = config::Config::default();
     // If flag `--theme` is present, copy theme to src
-    if args.is_present("theme") {
+    if args.get_flag("theme") {
         let theme_dir = book_dir.join("theme");
         println!();
         println!("Copying the default theme to {}", theme_dir.display());
         // Skip this if `--force` is present
-        if !args.is_present("force") && theme_dir.exists() {
+        if !args.get_flag("force") && theme_dir.exists() {
             println!("This could potentially overwrite files already present in that directory.");
             print!("\nAre you sure you want to continue? (y/n) ");
 
@@ -59,7 +51,7 @@ pub fn execute(args: &ArgMatches) -> Result<()> {
         }
     }
 
-    if let Some(ignore) = args.value_of("ignore") {
+    if let Some(ignore) = args.get_one::<String>("ignore").map(|s| s.as_str()) {
         match ignore {
             "git" => builder.create_gitignore(true),
             _ => builder.create_gitignore(false),
@@ -71,8 +63,8 @@ pub fn execute(args: &ArgMatches) -> Result<()> {
         }
     }
 
-    config.book.title = if args.is_present("title") {
+    config.book.title = if args.contains_id("title") {
-        args.value_of("title").map(String::from)
+        args.get_one::<String>("title").map(String::from)
     } else {
         request_book_title()
     };

src/cmd/mod.rs

@@ -2,6 +2,7 @@
 
 pub mod build;
 pub mod clean;
+pub mod command_prelude;
 pub mod init;
 #[cfg(feature = "serve")]
 pub mod serve;

src/cmd/serve.rs

@@ -1,7 +1,8 @@
+use super::command_prelude::*;
 #[cfg(feature = "watch")]
 use super::watch;
 use crate::{get_book_dir, open};
-use clap::{arg, App, Arg, ArgMatches};
+use clap::builder::NonEmptyStringValueParser;
 use futures_util::sink::SinkExt;
 use futures_util::StreamExt;
 use mdbook::errors::*;
@@ -18,43 +19,30 @@ use warp::Filter;
 const LIVE_RELOAD_ENDPOINT: &str = "__livereload";
 
 // Create clap subcommand arguments
-pub fn make_subcommand<'help>() -> App<'help> {
+pub fn make_subcommand() -> Command {
-    App::new("serve")
+    Command::new("serve")
         .about("Serves a book at http://localhost:3000, and rebuilds it on changes")
-        .arg(
+        .arg_dest_dir()
-            Arg::new("dest-dir")
+        .arg_root_dir()
-                .short('d')
-                .long("dest-dir")
-                .value_name("dest-dir")
-                .help(
-                    "Output directory for the book{n}\
-                    Relative paths are interpreted relative to the book's root directory.{n}\
-                    If omitted, mdBook uses build.build-dir from book.toml or defaults to `./book`.",
-                ),
-        )
-        .arg(arg!([dir]
-            "Root directory for the book{n}\
-            (Defaults to the Current Directory when omitted)"
-        ))
         .arg(
             Arg::new("hostname")
                 .short('n')
                 .long("hostname")
-                .takes_value(true)
+                .num_args(1)
                 .default_value("localhost")
-                .forbid_empty_values(true)
+                .value_parser(NonEmptyStringValueParser::new())
                 .help("Hostname to listen on for HTTP connections"),
         )
         .arg(
             Arg::new("port")
                 .short('p')
                 .long("port")
-                .takes_value(true)
+                .num_args(1)
                 .default_value("3000")
-                .forbid_empty_values(true)
+                .value_parser(NonEmptyStringValueParser::new())
                 .help("Port to use for HTTP connections"),
         )
-        .arg(arg!(-o --open "Opens the compiled book in a web browser"))
+        .arg_open()
 }
 
 // Serve command implementation
@@ -62,17 +50,17 @@ pub fn execute(args: &ArgMatches) -> Result<()> {
     let book_dir = get_book_dir(args);
     let mut book = MDBook::load(&book_dir)?;
 
-    let port = args.value_of("port").unwrap();
+    let port = args.get_one::<String>("port").unwrap();
-    let hostname = args.value_of("hostname").unwrap();
+    let hostname = args.get_one::<String>("hostname").unwrap();
-    let open_browser = args.is_present("open");
+    let open_browser = args.get_flag("open");
 
     let address = format!("{}:{}", hostname, port);
 
     let update_config = |book: &mut MDBook| {
         book.config
-            .set("output.html.live-reload-endpoint", &LIVE_RELOAD_ENDPOINT)
+            .set("output.html.live-reload-endpoint", LIVE_RELOAD_ENDPOINT)
             .expect("live-reload-endpoint update failed");
-        if let Some(dest_dir) = args.value_of("dest-dir") {
+        if let Some(dest_dir) = args.get_one::<PathBuf>("dest-dir") {
             book.config.build.build_dir = dest_dir.into();
         }
         // Override site-url for local serving of the 404 file

src/cmd/test.rs

@@ -1,63 +1,54 @@
+use super::command_prelude::*;
 use crate::get_book_dir;
-use clap::{arg, App, Arg, ArgMatches};
+use clap::builder::NonEmptyStringValueParser;
+use clap::{Arg, ArgAction, ArgMatches, Command};
 use mdbook::errors::Result;
 use mdbook::MDBook;
+use std::path::PathBuf;
 
 // Create clap subcommand arguments
-pub fn make_subcommand<'help>() -> App<'help> {
+pub fn make_subcommand() -> Command {
-    App::new("test")
+    Command::new("test")
         .about("Tests that a book's Rust code samples compile")
+        // FIXME: --dest-dir is unused by the test command, it should be removed
+        .arg_dest_dir()
+        .arg_root_dir()
         .arg(
-            Arg::new("dest-dir")
-                .short('d')
-                .long("dest-dir")
-                .value_name("dest-dir")
-                .help(
-                    "Output directory for the book{n}\
-                    Relative paths are interpreted relative to the book's root directory.{n}\
-                    If omitted, mdBook uses build.build-dir from book.toml or defaults to `./book`.",
-                ),
-        ).arg(
             Arg::new("chapter")
                 .short('c')
                 .long("chapter")
-                .value_name("chapter")
+                .value_name("chapter"),
-                .help(
+        )
-                    "Only test the specified chapter{n}\
+        .arg(
-                    Where the name of the chapter is defined in the SUMMARY.md file.{n}\
+            Arg::new("library-path")
-                    Use the special name \"?\" to the list of chapter names."
+                .short('L')
-                )
+                .long("library-path")
+                .value_name("dir")
+                .value_delimiter(',')
+                .num_args(1..)
+                .value_parser(NonEmptyStringValueParser::new())
+                .action(ArgAction::Append)
+                .help(
+                    "A comma-separated list of directories to add to the crate \
+                    search path when building tests",
+                ),
         )
-        .arg(arg!([dir]
-            "Root directory for the book{n}\
-            (Defaults to the Current Directory when omitted)"
-        ))
-        .arg(Arg::new("library-path")
-            .short('L')
-            .long("library-path")
-            .value_name("dir")
-            .takes_value(true)
-            .use_delimiter(true)
-            .require_delimiter(true)
-            .multiple_values(true)
-            .multiple_occurrences(true)
-            .forbid_empty_values(true)
-            .help("A comma-separated list of directories to add to {n}the crate search path when building tests"))
 }
 
 // test command implementation
 pub fn execute(args: &ArgMatches) -> Result<()> {
     let library_paths: Vec<&str> = args
-        .values_of("library-path")
+        .get_many("library-path")
-        .map(std::iter::Iterator::collect)
+        .map(|it| it.map(String::as_str).collect())
         .unwrap_or_default();
-    let chapter: Option<&str> = args.value_of("chapter");
+
+    let chapter: Option<&str> = args.get_one::<String>("chapter").map(|s| s.as_str());
 
     let book_dir = get_book_dir(args);
     let mut book = MDBook::load(&book_dir)?;
 
-    if let Some(dest_dir) = args.value_of("dest-dir") {
+    if let Some(dest_dir) = args.get_one::<PathBuf>("dest-dir") {
-        book.config.build.build_dir = dest_dir.into();
+        book.config.build.build_dir = dest_dir.to_path_buf();
     }
     match chapter {
         Some(_) => book.test_chapter(library_paths, chapter),

src/cmd/watch.rs

@@ -1,5 +1,5 @@
+use super::command_prelude::*;
 use crate::{get_book_dir, open};
-use clap::{arg, App, Arg, ArgMatches};
 use mdbook::errors::Result;
 use mdbook::utils;
 use mdbook::MDBook;
@@ -9,25 +9,12 @@ use std::thread::sleep;
 use std::time::Duration;
 
 // Create clap subcommand arguments
-pub fn make_subcommand<'help>() -> App<'help> {
+pub fn make_subcommand() -> Command {
-    App::new("watch")
+    Command::new("watch")
         .about("Watches a book's files and rebuilds it on changes")
-        .arg(
+        .arg_dest_dir()
-            Arg::new("dest-dir")
+        .arg_root_dir()
-                .short('d')
+        .arg_open()
-                .long("dest-dir")
-                .value_name("dest-dir")
-                .help(
-                    "Output directory for the book{n}\
-                    Relative paths are interpreted relative to the book's root directory.{n}\
-                    If omitted, mdBook uses build.build-dir from book.toml or defaults to `./book`.",
-                ),
-        )
-        .arg(arg!([dir]
-            "Root directory for the book{n}\
-            (Defaults to the Current Directory when omitted)"
-        ))
-        .arg(arg!(-o --open "Opens the compiled book in a web browser"))
 }
 
 // Watch command implementation
@@ -36,13 +23,13 @@ pub fn execute(args: &ArgMatches) -> Result<()> {
     let mut book = MDBook::load(&book_dir)?;
 
     let update_config = |book: &mut MDBook| {
-        if let Some(dest_dir) = args.value_of("dest-dir") {
+        if let Some(dest_dir) = args.get_one::<PathBuf>("dest-dir") {
             book.config.build.build_dir = dest_dir.into();
         }
     };
     update_config(&mut book);
 
-    if args.is_present("open") {
+    if args.get_flag("open") {
         book.build()?;
         let path = book.build_dir_for("html").join("index.html");
         if !path.exists() {

src/main.rs

@@ -5,7 +5,7 @@ extern crate log;
 
 use anyhow::anyhow;
 use chrono::Local;
-use clap::{App, AppSettings, Arg, ArgMatches};
+use clap::{Arg, ArgMatches, Command};
 use clap_complete::Shell;
 use env_logger::Builder;
 use log::LevelFilter;
@@ -13,7 +13,7 @@ use mdbook::utils;
 use std::env;
 use std::ffi::OsStr;
 use std::io::Write;
-use std::path::{Path, PathBuf};
+use std::path::PathBuf;
 
 mod cmd;
 
@@ -22,10 +22,10 @@ const VERSION: &str = concat!("v", crate_version!());
 fn main() {
     init_logger();
 
-    let app = create_clap_app();
+    let command = create_clap_command();
 
-    // Check which subcomamnd the user ran...
+    // Check which subcommand the user ran...
-    let res = match app.get_matches().subcommand() {
+    let res = match command.get_matches().subcommand() {
         Some(("init", sub_matches)) => cmd::init::execute(sub_matches),
         Some(("build", sub_matches)) => cmd::build::execute(sub_matches),
         Some(("clean", sub_matches)) => cmd::clean::execute(sub_matches),
@@ -35,15 +35,13 @@ fn main() {
         Some(("serve", sub_matches)) => cmd::serve::execute(sub_matches),
         Some(("test", sub_matches)) => cmd::test::execute(sub_matches),
         Some(("completions", sub_matches)) => (|| {
-            let shell: Shell = sub_matches
+            let shell = sub_matches
-                .value_of("shell")
+                .get_one::<Shell>("shell")
-                .ok_or_else(|| anyhow!("Shell name missing."))?
+                .ok_or_else(|| anyhow!("Shell name missing."))?;
-                .parse()
-                .map_err(|s| anyhow!("Invalid shell: {}", s))?;
 
-            let mut complete_app = create_clap_app();
+            let mut complete_app = create_clap_command();
             clap_complete::generate(
-                shell,
+                *shell,
                 &mut complete_app,
                 "mdbook",
                 &mut std::io::stdout().lock(),
@@ -61,13 +59,13 @@ fn main() {
 }
 
 /// Create a list of valid arguments and sub-commands
-fn create_clap_app() -> App<'static> {
+fn create_clap_command() -> Command {
-    let app = App::new(crate_name!())
+    let app = Command::new(crate_name!())
         .about(crate_description!())
         .author("Mathieu David <mathieudavid@mathieudavid.org>")
         .version(VERSION)
-        .setting(AppSettings::PropagateVersion)
+        .propagate_version(true)
-        .setting(AppSettings::ArgRequiredElseHelp)
+        .arg_required_else_help(true)
         .after_help(
             "For more information about a specific command, try `mdbook <command> --help`\n\
              The source code for mdBook is available at: https://github.com/rust-lang/mdBook",
@@ -77,12 +75,11 @@ fn create_clap_app() -> App<'static> {
         .subcommand(cmd::test::make_subcommand())
         .subcommand(cmd::clean::make_subcommand())
         .subcommand(
-            App::new("completions")
+            Command::new("completions")
                 .about("Generate shell completions for your shell to stdout")
                 .arg(
                     Arg::new("shell")
-                        .takes_value(true)
+                        .value_parser(clap::value_parser!(Shell))
-                        .possible_values(Shell::possible_values())
                         .help("the shell to generate completions for")
                         .value_name("SHELL")
                         .required(true),
@@ -124,11 +121,10 @@ fn init_logger() {
 }
 
 fn get_book_dir(args: &ArgMatches) -> PathBuf {
-    if let Some(dir) = args.value_of("dir") {
+    if let Some(p) = args.get_one::<PathBuf>("dir") {
         // Check if path is relative from current dir, or absolute...
-        let p = Path::new(dir);
         if p.is_relative() {
-            env::current_dir().unwrap().join(dir)
+            env::current_dir().unwrap().join(p)
         } else {
             p.to_path_buf()
         }
@@ -146,5 +142,5 @@ fn open<P: AsRef<OsStr>>(path: P) {
 
 #[test]
 fn verify_app() {
-    create_clap_app().debug_assert();
+    create_clap_command().debug_assert();
 }