feat: add hidden flag to traverse hidden files

Add the `hidden` and `no-hidden` flag that allows
configuring the traversal of hidden files.

Examples:

```
treefmt --hidden
```
will traverse hidden files.

```
treefmt --hidden --no-hidden
```
will not traverse hidden files, same as the default (`treefmt`).

```
treefmt --hidden --no-hidden --hidden
```
will traverse hidden files.

clippy.toml

@@ -1 +1 @@
-too-many-arguments-threshold = 9
+too-many-arguments-threshold = 10

docs/usage.md

@@ -64,6 +64,14 @@ treefmt [FLAGS] [OPTIONS] [--] [paths]...
 
 > Only apply selected formatters. Defaults to all formatters.
 
+`-H, --hidden`
+
+> Also traverse hidden files (files that start with a .). This behaviour can be overridden with the `no-hidden` flag.
+
+`--no-hidden`
+
+> Override the `--hidden` flag. Don't traverse hidden files.
+
 `--tree-root <tree-root>`
 
 > Set the path to the tree root directory where treefmt will look for the files to format. Defaults to the folder holding the `treefmt.toml` file. It’s mostly useful in combination with `--config-file` to specify the project root which won’t coincide with the directory holding `treefmt.toml`.

src/command/format.rs

@@ -9,6 +9,7 @@ pub fn format_cmd(
     work_dir: &Path,
     config_file: &Path,
     paths: &[PathBuf],
+    hidden: bool,
     no_cache: bool,
     clear_cache: bool,
     fail_on_change: bool,
@@ -55,6 +56,7 @@ pub fn format_cmd(
         &cache_dir,
         config_file,
         &paths,
+        hidden,
         no_cache,
         clear_cache,
         fail_on_change,

src/command/mod.rs

@@ -23,7 +23,7 @@ use std::{
 #[derive(Parser, Debug)]
 #[command(author, version, about, long_about = None)]
 pub struct Cli {
-    /// Create a new treefmt.toml
+    /// Create a new treefmt.toml.
     #[arg(short, long, default_value_t = false)]
     pub init: bool,
 
@@ -39,6 +39,15 @@ pub struct Cli {
     #[arg(short, long, default_value_t = false)]
     pub clear_cache: bool,
 
+    #[arg(long = "hidden", short = 'H')]
+    /// Include hidden files while traversing the tree.
+    /// Override with the --no-hidden flag.
+    pub hidden: bool,
+    /// Overrides the --hidden flag.
+    /// Don't include hidden files while traversing the tree.
+    #[arg(long, overrides_with = "hidden", hide = true)]
+    no_hidden: bool,
+
     /// Exit with error if any changes were made. Useful for CI.
     #[arg(
         long,
@@ -52,7 +61,7 @@ pub struct Cli {
     #[arg(long, default_value_t = false)]
     pub allow_missing_formatter: bool,
 
-    /// Log verbosity is based off the number of v used
+    /// Log verbosity is based off the number of v used.
     #[clap(flatten)]
     pub verbose: Verbosity,
 
@@ -158,6 +167,7 @@ pub fn run_cli(cli: &Cli) -> anyhow::Result<()> {
                         &cli.work_dir,
                         config_file,
                         &cli.paths,
+                        cli.hidden,
                         cli.no_cache,
                         cli.clear_cache,
                         cli.fail_on_change,

src/engine.rs

@@ -29,6 +29,7 @@ pub fn run_treefmt(
     cache_dir: &Path,
     treefmt_toml: &Path,
     paths: &[PathBuf],
+    hidden: bool,
     no_cache: bool,
     clear_cache: bool,
     fail_on_change: bool,
@@ -89,7 +90,7 @@ pub fn run_treefmt(
         cache.update_formatters(formatters.clone());
     }
 
-    let walker = build_walker(paths);
+    let walker = build_walker(paths, hidden);
 
     let matches = collect_matches_from_walker(walker, &formatters, &mut stats);
     stats.timed_debug("tree walk");
@@ -322,14 +323,15 @@ fn collect_matches_from_walker(
 }
 
 /// Configure and build the tree walker
-fn build_walker(paths: Vec<PathBuf>) -> Walk {
+fn build_walker(paths: Vec<PathBuf>, hidden: bool) -> Walk {
     // For some reason the WalkBuilder must start with one path, but can add more paths later.
     // unwrap: we checked before that there is at least one path in the vector
     let mut builder = WalkBuilder::new(paths.first().unwrap());
     // Add the other paths
     for path in paths[1..].iter() {
         builder.add(path);
     }
+    builder.hidden(!hidden);
     // TODO: builder has a lot of interesting options.
     // TODO: use build_parallel with a Visitor.
     //       See https://docs.rs/ignore/0.4.17/ignore/struct.WalkParallel.html#method.visit
@@ -981,7 +983,7 @@ mod tests {
 
         let formatters = load_formatters(root, tree_root, false, &None, &mut stats).unwrap();
 
-        let walker = build_walker(vec![tree_root.to_path_buf()]);
+        let walker = build_walker(vec![tree_root.to_path_buf()], false);
         let _matches = collect_matches_from_walker(walker, &formatters, &mut stats);
 
         assert_eq!(stats.traversed_files, 3);
@@ -1030,7 +1032,7 @@ mod tests {
 
         let formatters = load_formatters(root, tree_root, false, &None, &mut stats).unwrap();
 
-        let walker = build_walker(vec![tree_root.to_path_buf()]);
+        let walker = build_walker(vec![tree_root.to_path_buf()], false);
         let _matches = collect_matches_from_walker(walker, &formatters, &mut stats);
 
         assert_eq!(stats.traversed_files, 15);
@@ -1080,7 +1082,7 @@ mod tests {
 
         let formatters = load_formatters(root, tree_root, false, &None, &mut stats).unwrap();
 
-        let walker = build_walker(vec![tree_root.to_path_buf()]);
+        let walker = build_walker(vec![tree_root.to_path_buf()], false);
         let _matches = collect_matches_from_walker(walker, &formatters, &mut stats);
 
         assert_eq!(stats.traversed_files, 15);
@@ -1130,7 +1132,7 @@ mod tests {
 
         let formatters = load_formatters(root, tree_root, false, &None, &mut stats).unwrap();
 
-        let walker = build_walker(vec![tree_root.to_path_buf()]);
+        let walker = build_walker(vec![tree_root.to_path_buf()], false);
         let matches = collect_matches_from_walker(walker, &formatters, &mut stats);
 
         assert_eq!(stats.traversed_files, 12);
@@ -1213,7 +1215,7 @@ mod tests {
 
         let formatters = load_formatters(root, tree_root, false, &None, &mut stats).unwrap();
 
-        let walker = build_walker(vec![tree_root.to_path_buf()]);
+        let walker = build_walker(vec![tree_root.to_path_buf()], false);
         let matches = collect_matches_from_walker(walker, &formatters, &mut stats);
 
         assert_eq!(stats.traversed_files, 18);
@@ -1285,7 +1287,7 @@ mod tests {
 
         let formatters = load_formatters(root, tree_root, false, &None, &mut stats).unwrap();
 
-        let walker = build_walker(vec![tree_root.to_path_buf()]);
+        let walker = build_walker(vec![tree_root.to_path_buf()], false);
         let matches = collect_matches_from_walker(walker, &formatters, &mut stats);
 
         assert_eq!(stats.traversed_files, 7);
@@ -1347,7 +1349,7 @@ mod tests {
 
         let formatters = load_formatters(root, tree_root, false, &None, &mut stats).unwrap();
 
-        let walker = build_walker(vec![tree_root.to_path_buf()]);
+        let walker = build_walker(vec![tree_root.to_path_buf()], false);
         let matches = collect_matches_from_walker(walker, &formatters, &mut stats);
 
         assert_eq!(stats.traversed_files, 7);
@@ -1417,7 +1419,7 @@ mod tests {
 
         let formatters = load_formatters(root, tree_root, false, &None, &mut stats).unwrap();
 
-        let walker = build_walker(vec![tree_root.to_path_buf()]);
+        let walker = build_walker(vec![tree_root.to_path_buf()], false);
         let matches = collect_matches_from_walker(walker, &formatters, &mut stats);
 
         assert_eq!(stats.traversed_files, 8);
@@ -1486,7 +1488,7 @@ mod tests {
 
         let formatters = load_formatters(root, tree_root, false, &None, &mut stats).unwrap();
 
-        let walker = build_walker(vec![tree_root.to_path_buf()]);
+        let walker = build_walker(vec![tree_root.to_path_buf()], false);
         let matches = collect_matches_from_walker(walker, &formatters, &mut stats);
 
         assert_eq!(stats.traversed_files, 7);