Update dependencies and lints

crates/cli-mux/src/cli.rs

@@ -1,17 +1,18 @@
-use std::path::PathBuf;
+//! Command line argument parsing.
 
-use clap::Parser;
+use std::path::PathBuf;
 
 use crate::parser::Selector;
 
-#[derive(Parser)]
+/// Command line argument parser struct.
+#[derive(Debug, clap::Parser)]
 #[command(version, about, long_about = None)]
-pub struct Cli {
-	/// Dry run and print commands
+pub(crate) struct Args {
+	/// Dry run and print commands.
 	#[arg(short, long)]
 	dry_run: bool,
 
-	/// Stream selectors
+	/// Stream selectors.
 	#[arg(
 		short,
 		long,
@@ -21,29 +22,38 @@ pub struct Cli {
 	)]
 	selectors: Vec<Selector>,
 
-	/// The path to the directory to scan
+	/// The path to the directory to scan.
 	#[arg(value_name = "DIR")]
 	scan_dir: PathBuf,
 }
 
-impl Cli {
-	pub fn is_dry(&self) -> bool {
+impl Args {
+	/// True if the user requested a dry run.
+	pub(crate) const fn is_dry_run(&self) -> bool {
 		self.dry_run
 	}
 
-	pub fn selectors(&self) -> &[Selector] {
+	/// Returns a slice of provided [Selector].
+	pub(crate) fn selectors(&self) -> &[Selector] {
 		&self.selectors
 	}
 
-	pub fn scan_dir_path(&self) -> PathBuf {
-		fn expect_home_dir() -> PathBuf {
-			#[allow(clippy::expect_used)]
-			std::env::home_dir().expect("you do not have a home directory")
-		}
-
-		match self.scan_dir.strip_prefix("~/") {
-			Ok(path) => expect_home_dir().join(path),
-			Err(_) => self.scan_dir.to_owned(),
-		}
+	/// Get the path to scan.
+	///
+	/// # Panics
+	/// If the user doesn't have a home directory.
+	pub(crate) fn scan_dir_path(&self) -> PathBuf {
+		self.scan_dir.strip_prefix("~/").map_or_else(
+			|_| self.scan_dir.clone(),
+			|path| {
+				#[expect(
+					clippy::expect_used,
+					reason = "without a home directory this program is useless"
+				)]
+				std::env::home_dir()
+					.expect("you do not have a home directory")
+					.join(path)
+			},
+		)
 	}
 }

crates/cli-mux/src/main.rs

@@ -1,8 +1,8 @@
-//! flix-mux
+//! flix-mux.
 
 use core::time::Duration;
 
-use clap::Parser;
+use clap::Parser as _;
 use console::style;
 use indicatif::{HumanBytes, ProgressBar, ProgressStyle};
 
@@ -16,14 +16,17 @@ mod parser;
 mod probe;
 mod scan;
 
+#[cfg_attr(test, expect(clippy::missing_panics_doc, reason = "main function"))]
+#[expect(clippy::print_stderr, reason = "we want to print in a binary")]
+#[expect(clippy::print_stdout, reason = "we want to print in a binary")]
 fn main() {
-	let cli = cli::Cli::parse();
+	let cli = cli::Args::parse();
 
 	let (files, size) = scan_directory(
 		&cli.scan_dir_path(),
 		|| {
 			let progress = ProgressBar::new_spinner();
-			progress.set_message(format!("Scanning {:?}", &cli.scan_dir_path()));
+			progress.set_message(format!("Scanning {}", cli.scan_dir_path().display()));
 			progress.enable_steady_tick(Duration::from_millis(50));
 			progress
 		},
@@ -31,7 +34,8 @@ fn main() {
 		|len| {
 			let progress = ProgressBar::new(u64::try_from(len).unwrap_or(0));
 			progress.set_style(
-				#[expect(clippy::expect_used)]
+				#[expect(clippy::expect_used, reason = "panic if the template is invalid")]
+				#[expect(clippy::literal_string_with_formatting_args, reason = "template")]
 				ProgressStyle::with_template("[{elapsed_precise}] {wide_bar} {pos}/{len} ({msg})")
 					.expect("static template"),
 			);
@@ -40,19 +44,20 @@ fn main() {
 		|progress| progress.inc(1),
 		|progress| progress.finish_and_clear(),
 		|progress, msg| {
-			progress.suspend(|| eprintln!("{} {}", style("[WARN]").bold().yellow(), msg))
+			progress.suspend(|| eprintln!("{} {msg}", style("[WARN]").bold().yellow()));
 		},
 	);
 	println!("Found {} files ({})", files.len(), HumanBytes(size));
 
 	mux_files(
-		cli.is_dry(),
+		cli.is_dry_run(),
 		&files,
 		cli.selectors(),
 		|len| {
 			let progress = ProgressBar::new(u64::try_from(len).unwrap_or(0));
 			progress.set_style(
-				#[expect(clippy::expect_used)]
+				#[expect(clippy::expect_used, reason = "panic if the template is invalid")]
+				#[expect(clippy::literal_string_with_formatting_args, reason = "template")]
 				ProgressStyle::with_template("[{elapsed_precise}] {wide_bar} {pos}/{len} ({msg})")
 					.expect("static template"),
 			);
@@ -61,6 +66,6 @@ fn main() {
 		},
 		|progress| progress.inc(1),
 		|progress| progress.finish_with_message("done"),
-		|progress, msg| progress.suspend(|| eprintln!("{} {}", style("[ERR]").bold().red(), msg)),
+		|progress, msg| progress.suspend(|| eprintln!("{} {msg}", style("[ERR]").bold().red())),
 	);
 }

crates/cli-mux/src/model.rs

@@ -1,42 +1,61 @@
+//! Model for handling media streams.
+
 use std::path::PathBuf;
 
 use serde::Deserialize;
 
+/// Represents a file that was scanned.
 #[derive(Debug, Clone)]
-pub struct MediaFile {
+pub(crate) struct MediaFile {
+	/// The path to the file.
 	pub path: PathBuf,
+	/// The size of the file.
 	pub byte_size: u64,
+	/// The streams in the file.
 	pub streams: Streams,
 }
 
+/// Represents the collection of streams found in a media file.
 #[derive(Debug, Clone)]
-pub struct Streams {
+pub(crate) struct Streams {
+	/// The video streams.
 	pub video: Vec<VideoStream>,
+	/// The audio streams.
 	pub audio: Vec<AudioStream>,
+	/// The subtitle streams.
 	pub subtitle: Vec<SubtitleStream>,
 }
 
-pub trait FFStream: serde::de::DeserializeOwned {
+/// This trait helps with deserializing `ffmpeg` output.
+pub(crate) trait FFStream: serde::de::DeserializeOwned {
+	/// The type name that `ffmpeg` uses.
 	const FF_TYPE_NAME: &str;
 }
 
+/// Represents an individual video stream in a media file.
 #[derive(Debug, Clone, Deserialize)]
-pub struct VideoStream {
+pub(crate) struct VideoStream {
+	/// The name of the video codec.
 	codec_name: String,
+	/// Additional tags on the stream.
 	tags: Option<VideoTags>,
 }
 
+/// Represents tags on a video stream.
 #[derive(Debug, Clone, Deserialize)]
-pub struct VideoTags {
+pub(crate) struct VideoTags {
+	/// The language of the stream.
 	language: Option<String>,
 }
 
 impl VideoStream {
-	pub fn codec(&self) -> &str {
+	/// Get the video codec name.
+	pub(crate) fn codec(&self) -> &str {
 		&self.codec_name
 	}
 
-	pub fn language(&self) -> Option<&str> {
+	/// Get the stream language.
+	pub(crate) fn language(&self) -> Option<&str> {
 		self.tags.as_ref()?.language.as_deref()
 	}
 }
@@ -45,23 +64,30 @@ impl FFStream for VideoStream {
 	const FF_TYPE_NAME: &str = "v";
 }
 
+/// Represents an individual audio stream in a media file.
 #[derive(Debug, Clone, Deserialize)]
-pub struct AudioStream {
+pub(crate) struct AudioStream {
+	/// The name of the audio codec.
 	codec_name: String,
+	/// Additional tags on the stream.
 	tags: Option<AudioTags>,
 }
 
+/// Represents tags on an audio stream.
 #[derive(Debug, Clone, Deserialize)]
-pub struct AudioTags {
+pub(crate) struct AudioTags {
+	/// The language of the stream.
 	language: Option<String>,
 }
 
 impl AudioStream {
-	pub fn codec(&self) -> &str {
+	/// Get the audio codec name.
+	pub(crate) fn codec(&self) -> &str {
 		&self.codec_name
 	}
 
-	pub fn language(&self) -> Option<&str> {
+	/// Get the stream language.
+	pub(crate) fn language(&self) -> Option<&str> {
 		self.tags.as_ref()?.language.as_deref()
 	}
 }
@@ -70,28 +96,37 @@ impl FFStream for AudioStream {
 	const FF_TYPE_NAME: &str = "a";
 }
 
+/// Represents an individual subtitle stream in a media file.
 #[derive(Debug, Clone, Deserialize)]
-pub struct SubtitleStream {
+pub(crate) struct SubtitleStream {
+	/// The name of the subtitle codec.
 	codec_name: String,
+	/// Additional tags on the stream.
 	tags: Option<SubtitleTags>,
 }
 
+/// Represents tags on a subtitle stream.
 #[derive(Debug, Clone, Deserialize)]
-pub struct SubtitleTags {
+pub(crate) struct SubtitleTags {
+	/// The language of the stream.
 	language: Option<String>,
+	/// The title of the stream.
 	title: Option<String>,
 }
 
 impl SubtitleStream {
-	pub fn codec(&self) -> &str {
+	/// Get the subtitle codec name.
+	pub(crate) fn codec(&self) -> &str {
 		&self.codec_name
 	}
 
-	pub fn language(&self) -> Option<&str> {
+	/// Get the stream language.
+	pub(crate) fn language(&self) -> Option<&str> {
 		self.tags.as_ref()?.language.as_deref()
 	}
 
-	pub fn title(&self) -> Option<&str> {
+	/// Get the stream title.
+	pub(crate) fn title(&self) -> Option<&str> {
 		self.tags.as_ref()?.title.as_deref()
 	}
 }

crates/cli-mux/src/mux.rs

@@ -1,3 +1,5 @@
+//! Wrapper around `ffmpeg` to mux media files.
+
 use std::process::Command;
 
 use anyhow::{Context as _, Result};
@@ -5,14 +7,19 @@ use anyhow::{Context as _, Result};
 use crate::model::MediaFile;
 use crate::parser::{Matcher, Selector, StreamFlag, StreamType};
 
+/// Helper struct for tracking which output index is currently available.
 #[derive(Default)]
 struct OutputIndex {
+	/// The next free video index.
 	video: usize,
+	/// The next free audio index.
 	audio: usize,
+	/// The next free subtitle index.
 	subtitle: usize,
 }
 
-pub fn mux_files<T>(
+/// For each input file, apply all selectors and mux the selection.
+pub(crate) fn mux_files<T>(
 	dry_run: bool,
 	files: &[MediaFile],
 	selectors: &[Selector],
@@ -24,14 +31,20 @@ pub fn mux_files<T>(
 	let mut progress = fixed_length_start(files.len());
 	for file in files {
 		if let Err(err) = mux(dry_run, file, selectors) {
-			print_fn(&progress, &format!("{:?}", err));
+			print_fn(&progress, &format!("{err:?}"));
 		}
 		fixed_length_update(&mut progress);
 	}
 	fixed_length_end(progress);
 }
 
-#[expect(clippy::expect_used)]
+/// Apply all selectors and mux the file.
+///
+/// # Errors
+/// If the call to `ffmpeg` fails.
+///
+/// # Panics
+/// If the system fails to allocate a temporary file.
 fn mux(dry_run: bool, file: &MediaFile, selectors: &[Selector]) -> Result<()> {
 	let mut command = Command::new("ffmpeg");
 	let mut command = command.args(["-v", "error"]);
@@ -40,10 +53,14 @@ fn mux(dry_run: bool, file: &MediaFile, selectors: &[Selector]) -> Result<()> {
 	command = command.arg(file.path.as_os_str());
 
 	for selector in selectors {
-		command = command.args(
-			make_map_args(file, selector)
-				.with_context(|| format!("Failed to mux {:?}", file.path))?,
-		);
+		command = command.args(make_map_args(file, selector).with_context(|| {
+			let info = if dry_run {
+				format!("Streams:\n{file:#?}")
+			} else {
+				String::from("use -d for stream info")
+			};
+			format!("Failed to mux {}\n{info}", file.path.display())
+		})?);
 	}
 
 	command = command.args(["-c:v", "copy", "-c:a", "copy", "-c:s", "mov_text"]);
@@ -56,25 +73,34 @@ fn mux(dry_run: bool, file: &MediaFile, selectors: &[Selector]) -> Result<()> {
 	let mut ouput_index = OutputIndex::default();
 	for selector in selectors {
 		command = command.args(
-			make_metadata_args(file, selector, &mut ouput_index)
-				.with_context(|| format!("Failed to mux {:?}", file.path))?,
+			make_metadata_args(file, selector, &mut ouput_index).with_context(|| {
+				let info = if dry_run {
+					format!("Streams:\n{file:#?}")
+				} else {
+					String::from("use -d for stream info")
+				};
+				format!("Failed to mux {}\n{info}", file.path.display())
+			})?,
 		);
 	}
 
 	let temp_path = file.path.with_extension("mp4");
-	command = command.arg(temp_path.file_name().expect("file name exists"));
+	#[expect(clippy::expect_used, reason = "files must have names")]
+	{
+		command = command.arg(temp_path.file_name().expect("file name exists"));
+	}
 
 	if dry_run {
 		print_command(command);
 	} else {
 		let output = command
 			.output()
-			.with_context(|| format!("Failed to mux {:?}", file.path))?;
+			.with_context(|| format!("Failed to mux {}", file.path.display()))?;
 
 		if !output.status.success() {
 			anyhow::bail!(
-				"ffmpeg failed for {:?}:\n\n{}",
-				file.path,
+				"ffmpeg failed for {}:\n\n{}",
+				file.path.display(),
 				String::from_utf8_lossy(&output.stderr)
 			);
 		}
@@ -83,23 +109,31 @@ fn mux(dry_run: bool, file: &MediaFile, selectors: &[Selector]) -> Result<()> {
 	Ok(())
 }
 
+/// Generate the `-map` argument list for `ffmpeg`.
+///
+/// # Errors
+/// If the stream selection is unsatisfyable for the file.
 fn make_map_args(file: &MediaFile, selector: &Selector) -> Result<Vec<String>> {
-	let source_index = 0;
+	let source_index: u32 = 0;
 	let stream_type = selector.stream_type.as_ref();
 	let Some(stream_index) = find_stream_index(file, selector) else {
 		if selector.optional {
 			return Ok(vec![]);
-		} else {
-			anyhow::bail!("unsatisfied stream selection");
 		}
+
+		anyhow::bail!("unsatisfied stream selection");
 	};
 
 	Ok(vec![
 		String::from("-map"),
-		format!("{}:{}:{}", source_index, stream_type, stream_index),
+		format!("{source_index}:{stream_type}:{stream_index}"),
 	])
 }
 
+/// Generate the `-metadata` argument list for `ffmpeg`.
+///
+/// # Errors
+/// If the stream selection is unsatisfyable for the file.
 fn make_metadata_args(
 	file: &MediaFile,
 	selector: &Selector,
@@ -112,9 +146,9 @@ fn make_metadata_args(
 	let Some(_) = find_stream_index(file, selector) else {
 		if selector.optional {
 			return Ok(vec![]);
-		} else {
-			anyhow::bail!("unsatisfied stream selection");
 		}
+
+		anyhow::bail!("unsatisfied stream selection");
 	};
 
 	let counter = match selector.stream_type {
@@ -126,8 +160,8 @@ fn make_metadata_args(
 	*counter = counter.saturating_add(1);
 
 	let mut args = vec![
-		format!("-metadata:s:{}:{}", stream_type, stream_index),
-		format!("language={}", stream_language),
+		format!("-metadata:s:{stream_type}:{stream_index}"),
+		format!("language={stream_language}"),
 	];
 
 	if selector.stream_type == StreamType::Subtitle {
@@ -137,25 +171,26 @@ fn make_metadata_args(
 			None => match stream_language {
 				"eng" => "English",
 				"jpn" => "Japanese",
-				_ => anyhow::bail!("Unhandled subtitle language: {}", stream_language),
+				_ => anyhow::bail!("Unhandled subtitle language: {stream_language}"),
 			},
 		};
 
-		args.push(format!("-metadata:s:s:{}", stream_index));
-		args.push(format!("title={}", sub_title));
+		args.push(format!("-metadata:s:s:{stream_index}"));
+		args.push(format!("title={sub_title}"));
 	}
 
 	Ok(args)
 }
 
+/// Walk the streams of a file to match the given [Selector].
 fn find_stream_index(file: &MediaFile, selector: &Selector) -> Option<usize> {
 	let needs_forced = selector.flag == Some(StreamFlag::Forced);
 	let needs_sdh = selector.flag == Some(StreamFlag::Sdh);
 
 	match selector.stream_type {
-		StreamType::Video => match selector.matcher {
-			Matcher::Index(index) => (file.streams.video.len() > index).then_some(index),
-			Matcher::Language(ref language) => file
+		StreamType::Video => match &selector.matcher {
+			Matcher::Index(index) => (file.streams.video.len() > *index).then_some(*index),
+			Matcher::Language(language) => file
 				.streams
 				.video
 				.iter()
@@ -163,7 +198,7 @@ fn find_stream_index(file: &MediaFile, selector: &Selector) -> Option<usize> {
 				.filter(|(_, c)| c.language() == Some(language.as_str()))
 				.map(|(i, _)| i)
 				.next(),
-			Matcher::Codec(ref codec) => file
+			Matcher::Codec(codec) => file
 				.streams
 				.video
 				.iter()
@@ -172,9 +207,9 @@ fn find_stream_index(file: &MediaFile, selector: &Selector) -> Option<usize> {
 				.map(|(i, _)| i)
 				.next(),
 		},
-		StreamType::Audio => match selector.matcher {
-			Matcher::Index(index) => (file.streams.audio.len() > index).then_some(index),
-			Matcher::Language(ref language) => file
+		StreamType::Audio => match &selector.matcher {
+			Matcher::Index(index) => (file.streams.audio.len() > *index).then_some(*index),
+			Matcher::Language(language) => file
 				.streams
 				.audio
 				.iter()
@@ -182,7 +217,7 @@ fn find_stream_index(file: &MediaFile, selector: &Selector) -> Option<usize> {
 				.filter(|(_, c)| c.language() == Some(language.as_str()))
 				.map(|(i, _)| i)
 				.next(),
-			Matcher::Codec(ref codec) => file
+			Matcher::Codec(codec) => file
 				.streams
 				.audio
 				.iter()
@@ -191,9 +226,9 @@ fn find_stream_index(file: &MediaFile, selector: &Selector) -> Option<usize> {
 				.map(|(i, _)| i)
 				.next(),
 		},
-		StreamType::Subtitle => match selector.matcher {
-			Matcher::Index(index) => (file.streams.subtitle.len() > index).then_some(index),
-			Matcher::Language(ref language) => {
+		StreamType::Subtitle => match &selector.matcher {
+			Matcher::Index(index) => (file.streams.subtitle.len() > *index).then_some(*index),
+			Matcher::Language(language) => {
 				file.streams
 					.subtitle
 					.iter()
@@ -214,7 +249,7 @@ fn find_stream_index(file: &MediaFile, selector: &Selector) -> Option<usize> {
 					.map(|(i, _)| i)
 					.next()
 			}
-			Matcher::Codec(ref codec) => file
+			Matcher::Codec(codec) => file
 				.streams
 				.subtitle
 				.iter()
@@ -226,6 +261,8 @@ fn find_stream_index(file: &MediaFile, selector: &Selector) -> Option<usize> {
 	}
 }
 
+/// Print out the command to stdout.
+#[expect(clippy::print_stdout, reason = "the purpose is to print")]
 fn print_command(cmd: &Command) {
 	let program = cmd.get_program().to_string_lossy();
 
@@ -235,15 +272,16 @@ fn print_command(cmd: &Command) {
 		.collect::<Vec<_>>()
 		.join(" ");
 
-	println!("{} {}", program, args);
+	println!("{program} {args}");
 }
 
+/// Escape a string to be used by a shell.
 fn shell_escape(s: &str) -> String {
 	if s.chars()
 		.all(|c| c.is_ascii_alphanumeric() || "-_./".contains(c))
 	{
-		s.to_string()
+		s.to_owned()
 	} else {
-		format!("{:?}", s)
+		format!("{s:?}")
 	}
 }

crates/cli-mux/src/parser.rs

@@ -1,20 +1,26 @@
+//! Parsing types for `ffmpeg` output.
+
 use core::error::Error;
 use core::fmt;
 use core::str::FromStr;
 
+/// The type of a stream.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum StreamType {
+pub(crate) enum StreamType {
+	/// A video stream.
 	Video,
+	/// An audio stream.
 	Audio,
+	/// A subtitle stream.
 	Subtitle,
 }
 
 impl AsRef<str> for StreamType {
 	fn as_ref(&self) -> &str {
 		match self {
-			StreamType::Video => "v",
-			StreamType::Audio => "a",
-			StreamType::Subtitle => "s",
+			Self::Video => "v",
+			Self::Audio => "a",
+			Self::Subtitle => "s",
 		}
 	}
 }
@@ -24,18 +30,22 @@ impl FromStr for StreamType {
 
 	fn from_str(s: &str) -> Result<Self, Self::Err> {
 		match s {
-			"v" => Ok(StreamType::Video),
-			"a" => Ok(StreamType::Audio),
-			"s" => Ok(StreamType::Subtitle),
-			other => Err(ParseSelectorError::InvalidStreamType(other.to_string())),
+			"v" => Ok(Self::Video),
+			"a" => Ok(Self::Audio),
+			"s" => Ok(Self::Subtitle),
+			other => Err(ParseSelectorError::InvalidStreamType(other.to_owned())),
 		}
 	}
 }
 
+/// A property of a stream to match on.
 #[derive(Debug, Clone, PartialEq, Eq)]
-pub enum Matcher {
+pub(crate) enum Matcher {
+	/// Match a specific stream index.
 	Index(usize),
+	/// Match the first stream of the given language.
 	Language(String),
+	/// Match the first stream of the given codec.
 	Codec(String),
 }
 
@@ -44,19 +54,22 @@ impl FromStr for Matcher {
 
 	fn from_str(s: &str) -> Result<Self, Self::Err> {
 		if let Ok(idx) = s.parse::<usize>() {
-			return Ok(Matcher::Index(idx));
+			return Ok(Self::Index(idx));
 		}
 
 		if s.len() == 3 {
-			return Ok(Matcher::Language(s.to_ascii_lowercase()));
+			return Ok(Self::Language(s.to_ascii_lowercase()));
 		}
-		Ok(Matcher::Codec(s.to_ascii_lowercase()))
+		Ok(Self::Codec(s.to_ascii_lowercase()))
 	}
 }
 
+/// Flags applied to streams.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum StreamFlag {
+pub(crate) enum StreamFlag {
+	/// Forced flag.
 	Forced,
+	/// SDH flag.
 	Sdh,
 }
 
@@ -65,24 +78,31 @@ impl FromStr for StreamFlag {
 
 	fn from_str(s: &str) -> Result<Self, Self::Err> {
 		match s.to_ascii_lowercase().as_str() {
-			"forced" => Ok(StreamFlag::Forced),
-			"sdh" => Ok(StreamFlag::Sdh),
-			other => Err(ParseSelectorError::InvalidFlag(other.to_string())),
+			"forced" => Ok(Self::Forced),
+			"sdh" => Ok(Self::Sdh),
+			other => Err(ParseSelectorError::InvalidFlag(other.to_owned())),
 		}
 	}
 }
 
+/// A complete selector which has everything it needs to find a specific stream.
 #[derive(Debug, Clone, PartialEq, Eq)]
-pub struct Selector {
+pub(crate) struct Selector {
+	/// The type of the stream to select.
 	pub stream_type: StreamType,
+	/// The matcher to use when selecting.
 	pub matcher: Matcher,
+	/// A desired flag.
 	pub flag: Option<StreamFlag>,
+	/// Whether or not to bail if the stream cannot be found.
 	pub optional: bool,
+	/// The output language of the stream.
 	pub out_lang: String,
 }
 
 impl Selector {
-	pub fn language(&self) -> &str {
+	/// Get the target language of the selector.
+	pub(crate) fn language(&self) -> &str {
 		&self.out_lang
 	}
 }
@@ -125,7 +145,7 @@ impl FromStr for Selector {
 			(true, _) => return Err(ParseSelectorError::UnspecifiedLanguage),
 		};
 
-		Ok(Selector {
+		Ok(Self {
 			stream_type,
 			matcher,
 			flag,
@@ -135,15 +155,22 @@ impl FromStr for Selector {
 	}
 }
 
+/// Errors that can arise when parsing a selector string.
 #[derive(Debug)]
-pub enum ParseSelectorError {
+pub(crate) enum ParseSelectorError {
+	/// The selector string is empty.
 	Empty,
+	/// The selector string has an invalid format.
 	InvalidFormat,
+	/// The requested stream type in invalid.
 	InvalidStreamType(String),
+	/// The requested flag is invalid.
 	InvalidFlag(String),
+	/// The target language is unspecified.
 	UnspecifiedLanguage,
 }
 
+#[expect(clippy::missing_trait_methods, reason = "accept default methods")]
 impl Error for ParseSelectorError {}
 
 impl fmt::Display for ParseSelectorError {
@@ -151,8 +178,8 @@ impl fmt::Display for ParseSelectorError {
 		match self {
 			Self::Empty => write!(f, "selector was empty"),
 			Self::InvalidFormat => write!(f, "invalid selector format"),
-			Self::InvalidStreamType(s) => write!(f, "invalid stream type '{}'", s),
-			Self::InvalidFlag(s) => write!(f, "invalid stream flag '{}'", s),
+			Self::InvalidStreamType(s) => write!(f, "invalid stream type '{s}'"),
+			Self::InvalidFlag(s) => write!(f, "invalid stream flag '{s}'"),
 			Self::UnspecifiedLanguage => write!(f, "unspecified output language"),
 		}
 	}

crates/cli-mux/src/probe.rs

@@ -1,4 +1,6 @@
-use std::os::unix::fs::MetadataExt;
+//! Helpers for using `ffprobe` to gather stream information from media files.
+
+use std::os::unix::fs::MetadataExt as _;
 use std::process::Command;
 
 use anyhow::{Context as _, Result};
@@ -7,11 +9,20 @@ use walkdir::DirEntry;
 
 use crate::model::{FFStream, MediaFile, Streams};
 
+/// The top-level containing type for `ffprobe` output.
 #[derive(Debug, Deserialize)]
 struct FFProbeOutput<S> {
+	/// The list of returned streams.
 	streams: Vec<S>,
 }
 
+/// Calls `ffprobe` on a [`DirEntry`] to gather one type of stream.
+///
+/// # Errors
+/// Forwards any IO or parsing errors.
+///
+/// # Panics
+/// If the file path is not utf8.
 fn probe_file_streams<S: FFStream>(entry: &DirEntry) -> Result<Vec<S>> {
 	let output = Command::new("ffprobe")
 		.args([
@@ -22,16 +33,16 @@ fn probe_file_streams<S: FFStream>(entry: &DirEntry) -> Result<Vec<S>> {
 			"-show_streams",
 			"-select_streams",
 			S::FF_TYPE_NAME,
-			#[expect(clippy::expect_used)]
+			#[expect(clippy::expect_used, reason = "panic if path is not utf8")]
 			entry.path().to_str().expect("path should be utf8"),
 		])
 		.output()
-		.with_context(|| format!("Failed to run ffprobe on {:?}", entry.path()))?;
+		.with_context(|| format!("Failed to run ffprobe on {}", entry.path().display()))?;
 
 	if !output.status.success() {
 		anyhow::bail!(
-			"ffprobe failed for {:?}:\n\n{}",
-			entry.path(),
+			"ffprobe failed for {}:\n\n{}",
+			entry.path().display(),
 			String::from_utf8_lossy(&output.stderr)
 		);
 	}
@@ -40,7 +51,11 @@ fn probe_file_streams<S: FFStream>(entry: &DirEntry) -> Result<Vec<S>> {
 	Ok(parsed.streams)
 }
 
-pub fn probe_file(entry: &DirEntry) -> Result<MediaFile> {
+/// Calls `ffprobe` on a [`DirEntry`] to detect all streams.
+///
+/// # Errors
+/// Forwards any IO or parsing errors.
+pub(crate) fn probe_file(entry: &DirEntry) -> Result<MediaFile> {
 	Ok(MediaFile {
 		path: entry.path().to_path_buf(),
 		byte_size: entry.metadata()?.size(),

crates/cli-mux/src/scan.rs

@@ -1,3 +1,5 @@
+//! Helpers for filesystem scanning.
+
 use std::path::Path;
 
 use walkdir::WalkDir;
@@ -5,7 +7,8 @@ use walkdir::WalkDir;
 use crate::model::MediaFile;
 use crate::probe::probe_file;
 
-pub fn scan_directory<T>(
+/// Recursively scan a directory.
+pub(crate) fn scan_directory<T>(
 	path: &Path,
 	unknown_length_start: impl FnOnce() -> T,
 	unknown_length_end: impl FnOnce(T),
@@ -18,32 +21,26 @@ pub fn scan_directory<T>(
 	let files: Vec<_> = WalkDir::new(path)
 		.into_iter()
 		.filter_map(Result::ok)
-		.filter(|e| e.file_type().is_file())
 		.filter(|e| {
-			let is_mkv = e
-				.path()
-				.extension()
-				.unwrap_or_default()
-				.eq_ignore_ascii_case("mkv");
-			let is_mp4 = e
-				.path()
-				.extension()
-				.unwrap_or_default()
-				.eq_ignore_ascii_case("mp4");
-			is_mkv || is_mp4
+			#[expect(clippy::filetype_is_file, reason = "we only want regular files")]
+			e.file_type().is_file()
+		})
+		.filter(|e| {
+			let ext = e.path().extension().unwrap_or_default();
+			ext.eq_ignore_ascii_case("mkv") || ext.eq_ignore_ascii_case("mp4")
 		})
 		.collect();
 	unknown_length_end(spinner);
 
 	let mut progress = fixed_length_start(files.len());
-	let mut total_byte_size = 0u64;
+	let mut total_byte_size = 0_u64;
 	let files: Vec<_> = files
 		.iter()
 		.filter_map(|entry| {
 			let file = match probe_file(entry) {
 				Ok(file) => Some(file),
 				Err(err) => {
-					print_fn(&progress, &format!("{:?}", err));
+					print_fn(&progress, &format!("{err:?}"));
 					None
 				}
 			};