Rewatch cli help: do not show build command options in the root help

Author: cknitt

rewatch/src/cli.rs

@@ -22,6 +22,7 @@ pub enum FileExtension {
 #[derive(Parser, Debug)]
 #[command(version)]
 #[command(args_conflicts_with_subcommands = true)]
+#[command(after_help = "NOTE: If no subcommand is provided, `build` is run by default.")]
 pub struct Cli {
     /// Verbosity:
     /// -v -> Debug
@@ -35,10 +36,7 @@ pub struct Cli {
 
     /// The command to run. If not provided it will default to build.
     #[command(subcommand)]
-    pub command: Option<Command>,
-
-    #[command(flatten)]
-    pub build_args: BuildArgs,
+    pub command: Command,
 }
 
 #[derive(Args, Debug, Clone)]
@@ -164,7 +162,7 @@ impl From<BuildArgs> for WatchArgs {
 
 #[derive(Subcommand, Clone, Debug)]
 pub enum Command {
-    /// Build the project
+    /// Build the project (default command)
     Build(BuildArgs),
     /// Build, then start a watcher
     Watch(WatchArgs),

rewatch/src/main.rs

@@ -1,22 +1,25 @@
 use anyhow::Result;
 use clap::Parser;
 use log::LevelFilter;
-use std::{io::Write, path::Path};
+use std::{env, io::Write, path::Path};
 
 use rescript::{build, cli, cmd, format, lock, watcher};
 
 fn main() -> Result<()> {
-    let args = cli::Cli::parse();
+    let mut args: Vec<String> = env::args().collect();
+    handle_default_arg(&mut args);
 
-    let log_level_filter = args.verbose.log_level_filter();
+    let cli = cli::Cli::parse_from(args);
+
+    let log_level_filter = cli.verbose.log_level_filter();
 
     env_logger::Builder::new()
         .format(|buf, record| writeln!(buf, "{}:\n{}", record.level(), record.args()))
         .filter_level(log_level_filter)
         .target(env_logger::fmt::Target::Stdout)
         .init();
 
-    let mut command = args.command.unwrap_or(cli::Command::Build(args.build_args));
+    let mut command = cli.command;
 
     if let cli::Command::Build(build_args) = &command {
         if build_args.watch {
@@ -109,3 +112,17 @@ fn get_lock(folder: &str) -> lock::Lock {
         acquired_lock => acquired_lock,
     }
 }
+
+fn handle_default_arg(args: &mut Vec<String>) {
+    let first_arg = args.get(1);
+    let global_flags = ["-h", "--help", "-V", "--version"];
+
+    let needs_default_arg = match first_arg {
+        Some(arg) if !arg.starts_with("-") || global_flags.contains(&arg.as_str()) => false,
+        _ => true,
+    };
+
+    if needs_default_arg {
+        args.insert(1, "build".to_string());
+    }
+}