Squashed commit of the following:

commit c0487a3b8bb3d9df1e290579bbbd425f7707b5bd
Author: Akshay <[email protected]>
Date:   Thu Nov 4 18:46:03 2021 +0530

    use ignore crate to enforce simpler ignore rules

    - also respects .gitignore by default
    - adds new flag `-u` to unrestrict statix

5 files changed, 121 insertions, 100 deletions

diff --git a/bin/Cargo.toml b/bin/Cargo.toml
index e78cabd..aa789eb 100644
--- a/bin/Cargo.toml
+++ b/bin/Cargo.toml
@@ -12,7 +12,7 @@ description = "Lints and suggestions for the Nix programming language"
 ariadne = "0.1.3"
 rnix = "0.9.0"
 clap = "3.0.0-beta.4"
-globset = "0.4.8"
+ignore = "0.4.18"
 thiserror = "1.0.30"
 similar = "2.1.0"
 vfs = { path = "../vfs" }
diff --git a/bin/src/config.rs b/bin/src/config.rs
index 46bf60f..e0f5cbd 100644
--- a/bin/src/config.rs
+++ b/bin/src/config.rs
@@ -1,16 +1,10 @@
-use std::{
-    default::Default,
-    fmt, fs, io,
-    path::{Path, PathBuf},
-    str::FromStr,
-};
+use std::{default::Default, fmt, fs, path::PathBuf, str::FromStr};
+
+use crate::{dirs, err::ConfigErr};
 
 use clap::Clap;
-use globset::{Error as GlobError, GlobBuilder, GlobSet, GlobSetBuilder};
 use vfs::ReadOnlyVfs;
 
-use crate::err::ConfigErr;
-
 #[derive(Clap, Debug)]
 #[clap(version, author, about)]
 pub struct Opts {
@@ -40,6 +34,10 @@ pub struct Check {
     #[clap(short, long)]
     ignore: Vec<String>,
 
+    /// Don't respect .gitignore files
+    #[clap(short, long)]
+    unrestricted: bool,
+
     /// Output format.
     /// Supported values: stderr, errfmt, json (on feature flag only)
     #[clap(short = 'o', long, default_value_t, parse(try_from_str))]
@@ -48,8 +46,9 @@ pub struct Check {
 
 impl Check {
     pub fn vfs(&self) -> Result<ReadOnlyVfs, ConfigErr> {
-        let files = walk_with_ignores(&self.ignore, &self.target)?;
-        vfs(files)
+        let ignore = dirs::build_ignore_set(&self.ignore, &self.target, self.unrestricted)?;
+        let files = dirs::walk_nix_files(ignore, &self.target)?;
+        vfs(files.collect::<Vec<_>>())
     }
 }
 
@@ -63,6 +62,10 @@ pub struct Fix {
     #[clap(short, long)]
     ignore: Vec<String>,
 
+    /// Don't respect .gitignore files
+    #[clap(short, long)]
+    unrestricted: bool,
+
     /// Do not fix files in place, display a diff instead
     #[clap(short, long = "dry-run")]
     pub diff_only: bool,
@@ -70,8 +73,9 @@ pub struct Fix {
 
 impl Fix {
     pub fn vfs(&self) -> Result<ReadOnlyVfs, ConfigErr> {
-        let files = walk_with_ignores(&self.ignore, &self.target)?;
-        vfs(files)
+        let ignore = dirs::build_ignore_set(&self.ignore, &self.target, self.unrestricted)?;
+        let files = dirs::walk_nix_files(ignore, &self.target)?;
+        vfs(files.collect::<Vec<_>>())
     }
 }
 
@@ -97,62 +101,6 @@ pub struct Explain {
     pub target: u32,
 }
 
-mod dirs {
-    use std::{
-        fs,
-        io::{self, Error, ErrorKind},
-        path::{Path, PathBuf},
-    };
-
-    #[derive(Default, Debug)]
-    pub struct Walker {
-        dirs: Vec<PathBuf>,
-        files: Vec<PathBuf>,
-    }
-
-    impl Walker {
-        pub fn new<P: AsRef<Path>>(target: P) -> io::Result<Self> {
-            let target = target.as_ref().to_path_buf();
-            if !target.exists() {
-                Err(Error::new(
-                    ErrorKind::NotFound,
-                    format!("file not found: {}", target.display()),
-                ))
-            } else if target.is_dir() {
-                Ok(Self {
-                    dirs: vec![target],
-                    ..Default::default()
-                })
-            } else {
-                Ok(Self {
-                    files: vec![target],
-                    ..Default::default()
-                })
-            }
-        }
-    }
-
-    impl Iterator for Walker {
-        type Item = PathBuf;
-        fn next(&mut self) -> Option<Self::Item> {
-            if let Some(dir) = self.dirs.pop() {
-                if dir.is_dir() {
-                    for entry in fs::read_dir(dir).ok()? {
-                        let entry = entry.ok()?;
-                        let path = entry.path();
-                        if path.is_dir() {
-                            self.dirs.push(path);
-                        } else if path.is_file() {
-                            self.files.push(path);
-                        }
-                    }
-                }
-            }
-            self.files.pop()
-        }
-    }
-}
-
 fn parse_line_col(src: &str) -> Result<(usize, usize), ConfigErr> {
     let parts = src.split(',');
     match parts.collect::<Vec<_>>().as_slice() {
@@ -184,33 +132,6 @@ fn parse_warning_code(src: &str) -> Result<u32, ConfigErr> {
     }
 }
 
-fn build_ignore_set(ignores: &[String]) -> Result<GlobSet, GlobError> {
-    let mut set = GlobSetBuilder::new();
-    for pattern in ignores {
-        let glob = GlobBuilder::new(pattern).build()?;
-        set.add(glob);
-    }
-    set.build()
-}
-
-fn walk_nix_files<P: AsRef<Path>>(target: P) -> Result<impl Iterator<Item = PathBuf>, io::Error> {
-    let walker = dirs::Walker::new(target)?;
-    Ok(walker.filter(|path: &PathBuf| matches!(path.extension(), Some(e) if e == "nix")))
-}
-
-fn walk_with_ignores<P: AsRef<Path>>(
-    ignores: &[String],
-    target: P,
-) -> Result<Vec<PathBuf>, ConfigErr> {
-    let ignores = build_ignore_set(ignores).map_err(|err| {
-        ConfigErr::InvalidGlob(err.glob().map(|i| i.to_owned()), err.kind().clone())
-    })?;
-
-    Ok(walk_nix_files(&target)?
-        .filter(|path| !ignores.is_match(path))
-        .collect())
-}
-
 fn vfs(files: Vec<PathBuf>) -> Result<ReadOnlyVfs, ConfigErr> {
     let mut vfs = ReadOnlyVfs::default();
     for file in files.iter() {
diff --git a/bin/src/dirs.rs b/bin/src/dirs.rs
new file mode 100644
index 0000000..d3fe612
--- /dev/null
+++ b/bin/src/dirs.rs
@@ -0,0 +1,99 @@
+use std::{
+    fs,
+    io::{self, Error, ErrorKind},
+    path::{Path, PathBuf},
+};
+
+use crate::dirs;
+
+use ignore::{
+    gitignore::{Gitignore, GitignoreBuilder},
+    Error as IgnoreError, Match,
+};
+
+#[derive(Debug)]
+pub struct Walker {
+    dirs: Vec<PathBuf>,
+    files: Vec<PathBuf>,
+    ignore: Gitignore,
+}
+
+impl Walker {
+    pub fn new<P: AsRef<Path>>(target: P, ignore: Gitignore) -> io::Result<Self> {
+        let target = target.as_ref().to_path_buf();
+        if !target.exists() {
+            Err(Error::new(
+                ErrorKind::NotFound,
+                format!("file not found: {}", target.display()),
+            ))
+        } else if target.is_dir() {
+            Ok(Self {
+                dirs: vec![target],
+                files: vec![],
+                ignore,
+            })
+        } else {
+            Ok(Self {
+                dirs: vec![],
+                files: vec![target],
+                ignore,
+            })
+        }
+    }
+}
+
+impl Iterator for Walker {
+    type Item = PathBuf;
+    fn next(&mut self) -> Option<Self::Item> {
+        if let Some(dir) = self.dirs.pop() {
+            if dir.is_dir() {
+                if let Match::None | Match::Whitelist(_) = self.ignore.matched(&dir, true) {
+                    for entry in fs::read_dir(&dir).ok()? {
+                        let entry = entry.ok()?;
+                        let path = entry.path();
+                        if path.is_dir() {
+                            self.dirs.push(path);
+                        } else if path.is_file() {
+                            self.files.push(path);
+                        }
+                    }
+                }
+            }
+        }
+        self.files.pop()
+    }
+}
+
+pub fn build_ignore_set<P: AsRef<Path>>(
+    ignore: &[String],
+    target: P,
+    unrestricted: bool,
+) -> Result<Gitignore, IgnoreError> {
+    let gitignore_path = target.as_ref().join(".gitignore");
+
+    // Looks like GitignoreBuilder::new does not source globs
+    // within gitignore_path by default, we have to enforce that
+    // using GitignoreBuilder::add. Probably a bug in the ignore
+    // crate?
+    let mut gitignore = GitignoreBuilder::new(&gitignore_path);
+
+    // if we are to "restrict" aka "respect" .gitignore, then
+    // add globs from gitignore path as well
+    if !unrestricted {
+        gitignore.add(&gitignore_path);
+    }
+
+    for i in ignore {
+        gitignore.add_line(None, i.as_str())?;
+    }
+
+    gitignore.build()
+}
+
+pub fn walk_nix_files<P: AsRef<Path>>(
+    ignore: Gitignore,
+    target: P,
+) -> Result<impl Iterator<Item = PathBuf>, io::Error> {
+    let walker = dirs::Walker::new(target, ignore)?;
+    Ok(walker.filter(|path: &PathBuf| matches!(path.extension(), Some(e) if e == "nix")))
+}
diff --git a/bin/src/err.rs b/bin/src/err.rs
index 1e52c2b..b776d9f 100644
--- a/bin/src/err.rs
+++ b/bin/src/err.rs
@@ -1,13 +1,13 @@
 use std::io;
 
-use globset::ErrorKind;
+// use globset::ErrorKind;
 // use rnix::parser::ParseError;
 use thiserror::Error;
 
 #[derive(Error, Debug)]
 pub enum ConfigErr {
-    #[error("error parsing glob `{0:?}`: {1}")]
-    InvalidGlob(Option<String>, ErrorKind),
+    #[error("error parsing ignore list `{0}`")]
+    InvalidGlob(#[from] ignore::Error),
     #[error("path error: {0}")]
     InvalidPath(#[from] io::Error),
     #[error("unable to parse `{0}` as line and column")]
diff --git a/bin/src/main.rs b/bin/src/main.rs
index 4090701..3adf42e 100644
--- a/bin/src/main.rs
+++ b/bin/src/main.rs
@@ -1,4 +1,5 @@
 mod config;
+mod dirs;
 mod err;
 mod explain;
 mod fix;