Add ignore flag

Add the ignore flag which make cargo-machete respect .ignore and
.gitignore files when searching for files.

Cargo.toml

@@ -16,12 +16,12 @@ argh = "0.1.9"
 cargo_metadata = "0.18.0"
 cargo_toml = "0.16.2"
 grep = "0.2.8"
+ignore = "0.4.20"
 log = "0.4.16"
 pretty_env_logger = "0.5.0"
 rayon = "1.5.2"
 serde = "1.0.136"
 toml_edit = "0.20.0"
-walkdir = "2.3.2"
 
 # Uncomment this for profiling.
 #[profile.release]

src/main.rs

@@ -6,7 +6,6 @@ use rayon::prelude::*;
 use std::path::Path;
 use std::str::FromStr;
 use std::{fs, path::PathBuf};
-use walkdir::WalkDir;
 
 #[derive(Clone, Copy)]
 pub(crate) enum UseCargoMetadata {
@@ -62,6 +61,10 @@ struct MacheteArgs {
     #[argh(switch)]
     fix: bool,
 
+    /// respect ignore files (.gitignore, .ignore, etc.) when searching for files.
+    #[argh(switch)]
+    ignore: bool,
+
     /// print version.
     #[argh(switch)]
     version: bool,
@@ -71,21 +74,28 @@ struct MacheteArgs {
     paths: Vec<PathBuf>,
 }
 
-fn collect_paths(path: &Path, skip_target_dir: bool) -> Result<Vec<PathBuf>, walkdir::Error> {
+fn collect_paths(
+    path: &Path,
+    skip_target_dir: bool,
+    respect_ignore_files: bool,
+) -> Result<Vec<PathBuf>, ignore::Error> {
     // Find directory entries.
-    let walker = WalkDir::new(path).into_iter();
+    let mut builder = ignore::WalkBuilder::new(path);
 
-    let manifest_path_entries = if skip_target_dir {
-        walker
-            .filter_entry(|entry| !entry.path().ends_with("target"))
-            .collect()
-    } else {
-        walker.collect::<Vec<_>>()
-    };
+    builder.git_exclude(respect_ignore_files);
+    builder.git_global(respect_ignore_files);
+    builder.git_ignore(respect_ignore_files);
+    builder.ignore(respect_ignore_files);
+
+    if skip_target_dir {
+        builder.filter_entry(|entry| !entry.path().ends_with("target"));
+    }
+
+    let walker = builder.build();
 
     // Keep only errors and `Cargo.toml` files (filter), then map correct paths into owned
     // `PathBuf`.
-    manifest_path_entries
+    walker
         .into_iter()
         .filter(|entry| match entry {
             Ok(entry) => entry.file_name() == "Cargo.toml",
@@ -142,7 +152,7 @@ fn run_machete() -> anyhow::Result<bool> {
     let mut walkdir_errors = Vec::new();
 
     for path in args.paths {
-        let manifest_path_entries = match collect_paths(&path, args.skip_target_dir) {
+        let manifest_path_entries = match collect_paths(&path, args.skip_target_dir, args.ignore) {
             Ok(entries) => entries,
             Err(err) => {
                 walkdir_errors.push(err);
@@ -291,12 +301,21 @@ fn test_ignore_target() {
     let entries = collect_paths(
         &PathBuf::from(TOP_LEVEL).join("./integration-tests/with-target/"),
         true,
+        false,
     );
     assert!(entries.unwrap().is_empty());
 
     let entries = collect_paths(
         &PathBuf::from(TOP_LEVEL).join("./integration-tests/with-target/"),
         false,
+        true,
+    );
+    assert!(entries.unwrap().is_empty());
+
+    let entries = collect_paths(
+        &PathBuf::from(TOP_LEVEL).join("./integration-tests/with-target/"),
+        false,
+        false,
     );
     assert!(!entries.unwrap().is_empty());
 }

src/search_unused.rs

@@ -11,7 +11,6 @@ use std::{
     error::{self, Error},
     path::{Path, PathBuf},
 };
-use walkdir::WalkDir;
 
 use crate::UseCargoMetadata;
 #[cfg(test)]
@@ -146,10 +145,23 @@ fn collect_paths(dir_path: &Path, analysis: &PackageAnalysis) -> Vec<PathBuf> {
         trace!("adding src/ since paths was empty");
     }
 
+    // Unfortunately WalkBuilder does not implement `std::iter::FromIterator`.
+    let walk_builder = {
+        let mut roots = root_paths.into_iter().map(|p| dir_path.join(p));
+        let builder = ignore::WalkBuilder::new(
+            roots
+                .next()
+                .unwrap_or_else(|| unreachable!("root_paths should contain at least one entry")),
+        );
+        roots.fold(builder, |mut builder, root| {
+            builder.add(root);
+            builder
+        })
+    };
+
     // Collect all final paths for the crate first.
-    let paths: Vec<PathBuf> = root_paths
-        .iter()
-        .flat_map(|root| WalkDir::new(dir_path.join(root)).into_iter())
+    let paths = walk_builder
+        .build()
         .filter_map(|result| {
             let dir_entry = match result {
                 Ok(dir_entry) => dir_entry,
@@ -158,7 +170,7 @@ fn collect_paths(dir_path: &Path, analysis: &PackageAnalysis) -> Vec<PathBuf> {
                     return None;
                 }
             };
-            if !dir_entry.file_type().is_file() {
+            if !dir_entry.file_type()?.is_file() {
                 return None;
             }
             if dir_entry