properly document CLI options

src/cli.rs

@@ -1,6 +1,6 @@
 use std::path::PathBuf;
 
-use clap::{value_parser, Parser};
+use clap::{value_parser, Parser, ValueEnum};
 use color_eyre::Result;
 use serde_derive::{Deserialize, Serialize};
 use tracing::trace;
@@ -15,19 +15,31 @@ use crate::{builder::KatsuBuilder, config::Manifest};
 #[derive(Parser, Debug)]
 #[command(author, version, about)]
 pub struct KatsuCli {
+	/// Enable verbose output
 	#[arg(short, long, default_value = "false")]
 	verbose: bool,
 
 	/// Config file location
 	config: Option<PathBuf>,
 
-	#[arg(short, long, value_parser = value_parser!(OutputFormat))]
+	#[arg(short, long)]
+	#[arg(value_enum)]
+	/// Format of the artifact Katsu should output
 	output: OutputFormat,
-	#[arg(short, long,env = "KATSU_SKIP_PHASES", value_parser = value_parser!(SkipPhases), default_value = "")]
-	skip_phases: SkipPhases,
+
+	/// Skip individual phases
+	/// 
+	/// By default, no phases are skipped for any format
+	/// 
+	#[arg(short, long,env = "KATSU_SKIP_PHASES", value_parser = value_parser!(SkipPhases))]
+	#[arg()]
+	skip_phases: Option<SkipPhases>,
 
 	#[arg(long)]
-	/// Override architecture to build for
+	/// Override architecture to build for, makes use of DNF's `--arch` option
+	/// and chroots using userspace QEMU emulation if necessary
+	/// 
+	/// By default, Katsu will build for the host architecture
 	arch: Option<String>,
 
 	#[arg(long, short = 'O')]
@@ -50,11 +62,16 @@ impl From<&str> for SkipPhases {
 	}
 }
 
-#[derive(Serialize, Deserialize, Clone, Copy, Debug)]
+#[derive(Serialize, Deserialize, Clone, Copy, Debug, ValueEnum)]
 pub enum OutputFormat {
+	/// Creates a hybrid, bootable ISO-9660 image (with El Torito extensions)
 	Iso,
+	/// Creates a raw disk image that can either be flashed to a block device,
+	/// loopback mounted, or used as a virtual disk image
 	DiskImage,
+	/// Install to a block device directly
 	Device,
+	/// Simply copies the root tree to a directory
 	Folder,
 }
 
@@ -101,7 +118,7 @@ pub fn parse(cli: KatsuCli) -> Result<()> {
 
 	trace!(?manifest, "Loaded manifest");
 
-	let builder = KatsuBuilder::new(manifest, cli.output, cli.skip_phases)?;
+	let builder = KatsuBuilder::new(manifest, cli.output, cli.skip_phases.unwrap_or_default())?;
 
 	tracing::info!("Building image");
 	builder.build()?;