Respect `applies_in` scope when processing nested ignores (#746)

Previously, when importing multiple nested ignore files, some info from
the parent—notably the "root" path—would be inherited. This lead to some
problems with matching of "pseudo-absolute" rules (those with a leading
slash) in nested ignore files (see #745 for more details). To fix this,
we now fully isolate each path of the tree during the import process.
This leads to more accurate, though unfortunately slightly less
performant, rule matching. The only time a builder is reused now is if
two input files have the same `applies_in` value, in which case they are
merged together.

I have added tests to ensure correctness and prevent a regression. I
also was careful to make sure no previous tests broke in any way (all
changes to existing tests were made in isolation, and thus are not
affected by the logic changes). As far as I can tell, the only behavior
change is that now some previously-ignored rules will now be applied,
which could, in very rare configurations, lead to files being
unintentionally ignored. However, due to the aforementioned logic bug,
those files were all ignored by git already, so I suspect the number of
people actually caught off guard by this change to be extremely low,
likely zero.

Fixes #745.

Cargo.lock

@@ -1936,6 +1936,7 @@ dependencies = [
  "thiserror",
  "tokio",
  "tracing",
+ "tracing-subscriber",
 ]
 
 [[package]]

crates/filterer/ignore/tests/filtering.rs

@@ -60,7 +60,7 @@ fn folders_suite(filterer: &IgnoreFilterer, name: &str) {
 
 #[tokio::test]
 async fn globs() {
-	let filterer = filt("", &[file("globs")]).await;
+	let filterer = filt("", &[file("globs").applies_globally()]).await;
 
 	// Unmatched
 	filterer.file_does_pass("FINAL-FINAL.docx");
@@ -214,8 +214,8 @@ async fn scopes() {
 	let filterer = filt(
 		"",
 		&[
-			file("scopes-global"),
-			file("scopes-local").applies_in(""),
+			file("scopes-global").applies_globally(),
+			file("scopes-local"),
 			file("scopes-sublocal").applies_in("tests"),
 			file("none-allowed").applies_in("tests/child"),
 		],

crates/filterer/ignore/tests/helpers/mod.rs

@@ -187,24 +187,27 @@ pub async fn ignore_filt(origin: &str, ignore_files: &[IgnoreFile]) -> IgnoreFil
 }
 
 pub fn ig_file(name: &str) -> IgnoreFile {
-	let path = std::fs::canonicalize(".")
-		.unwrap()
-		.join("tests")
-		.join("ignores")
-		.join(name);
+	let origin = std::fs::canonicalize(".").unwrap();
+	let path = origin.join("tests").join("ignores").join(name);
 	IgnoreFile {
 		path,
-		applies_in: None,
+		applies_in: Some(origin),
 		applies_to: None,
 	}
 }
 
 pub trait Applies {
+	fn applies_globally(self) -> Self;
 	fn applies_in(self, origin: &str) -> Self;
 	fn applies_to(self, project_type: ProjectType) -> Self;
 }
 
 impl Applies for IgnoreFile {
+	fn applies_globally(mut self) -> Self {
+		self.applies_in = None;
+		self
+	}
+
 	fn applies_in(mut self, origin: &str) -> Self {
 		let origin = std::fs::canonicalize(".").unwrap().join(origin);
 		self.applies_in = Some(origin);

crates/ignore-files/Cargo.toml

@@ -36,3 +36,6 @@ features = [
 [dependencies.project-origins]
 version = "1.2.1"
 path = "../project-origins"
+
+[dev-dependencies]
+tracing-subscriber = "0.3.6"

crates/ignore-files/src/filter.rs

@@ -115,14 +115,9 @@ impl IgnoreFilter {
 
 			let applies_in = get_applies_in_path(origin, &file);
 
-			let parent_ignore = ignores_trie
-				.get_ancestor_value(&applies_in.display().to_string())
-				// unwrap will always succeed because we created an entry with the root of the origin
-				.unwrap();
-
-			let mut builder = parent_ignore
-				.builder
-				.clone()
+			let mut builder = ignores_trie
+				.get(&applies_in.display().to_string())
+				.and_then(|node| node.builder.clone())
 				.unwrap_or_else(|| GitignoreBuilder::new(&applies_in));
 
 			for line in content.lines() {
@@ -313,17 +308,46 @@ impl IgnoreFilter {
 	pub fn match_path(&self, path: &Path, is_dir: bool) -> Match<&Glob> {
 		let path = dunce::simplified(path);
 
-		let Some(ignores) = self.ignores.get_ancestor_value(&path.display().to_string()) else {
-			trace!(?path, "no ignores for path");
-			return Match::None;
-		};
+		let mut search_path = path;
+		loop {
+			let Some(trie_node) = self
+				.ignores
+				.get_ancestor(&search_path.display().to_string())
+			else {
+				trace!(?path, ?search_path, "no ignores for path");
+				return Match::None;
+			};
 
-		if path.strip_prefix(&self.origin).is_ok() {
-			trace!("checking against path or parents");
-			ignores.gitignore.matched_path_or_any_parents(path, is_dir)
-		} else {
-			trace!("checking against path only");
-			ignores.gitignore.matched(path, is_dir)
+			// Unwrap will always succeed because every node has an entry.
+			let ignores = trie_node.value().unwrap();
+
+			let match_ = if path.strip_prefix(&self.origin).is_ok() {
+				trace!(?path, ?search_path, "checking against path or parents");
+				ignores.gitignore.matched_path_or_any_parents(path, is_dir)
+			} else {
+				trace!(?path, ?search_path, "checking against path only");
+				ignores.gitignore.matched(path, is_dir)
+			};
+
+			match match_ {
+				Match::None => {
+					trace!(
+						?path,
+						?search_path,
+						"no match found, searching for parent ignores"
+					);
+					// Unwrap will always succeed because every node has an entry.
+					let trie_path = Path::new(trie_node.key().unwrap());
+					if let Some(trie_parent) = trie_path.parent() {
+						trace!(?path, ?search_path, "checking parent ignore");
+						search_path = trie_parent;
+					} else {
+						trace!(?path, ?search_path, "no parent ignore found");
+						return Match::None;
+					}
+				}
+				_ => return match_,
+			}
 		}
 	}
 

crates/ignore-files/tests/filtering.rs

@@ -0,0 +1,69 @@
+mod helpers;
+
+use helpers::ignore_tests::*;
+
+#[tokio::test]
+async fn globals() {
+	let filter = filt(
+		"tree",
+		&[
+			file("global/first").applies_globally(),
+			file("global/second").applies_globally(),
+		],
+	)
+	.await;
+
+	// Both ignores should be loaded as global
+	filter.agnostic_fail("/apples");
+	filter.agnostic_fail("/oranges");
+
+	// Sanity check
+	filter.agnostic_pass("/kiwi");
+}
+
+#[tokio::test]
+async fn tree() {
+	let filter = filt("tree", &[file("tree/base"), file("tree/branch/inner")]).await;
+
+	// "oranges" is not ignored at any level
+	filter.agnostic_pass("tree/oranges");
+	filter.agnostic_pass("tree/branch/oranges");
+	filter.agnostic_pass("tree/branch/inner/oranges");
+	filter.agnostic_pass("tree/other/oranges");
+
+	// "apples" should only be ignored at the root
+	filter.agnostic_fail("tree/apples");
+	filter.agnostic_pass("tree/branch/apples");
+	filter.agnostic_pass("tree/branch/inner/apples");
+	filter.agnostic_pass("tree/other/apples");
+
+	// "carrots" should be ignored at any level
+	filter.agnostic_fail("tree/carrots");
+	filter.agnostic_fail("tree/branch/carrots");
+	filter.agnostic_fail("tree/branch/inner/carrots");
+	filter.agnostic_fail("tree/other/carrots");
+
+	// "pineapples/grapes" should only be ignored at the root
+	filter.agnostic_fail("tree/pineapples/grapes");
+	filter.agnostic_pass("tree/branch/pineapples/grapes");
+	filter.agnostic_pass("tree/branch/inner/pineapples/grapes");
+	filter.agnostic_pass("tree/other/pineapples/grapes");
+
+	// "cauliflowers" should only be ignored at the root of "branch/"
+	filter.agnostic_pass("tree/cauliflowers");
+	filter.agnostic_fail("tree/branch/cauliflowers");
+	filter.agnostic_pass("tree/branch/inner/cauliflowers");
+	filter.agnostic_pass("tree/other/cauliflowers");
+
+	// "artichokes" should be ignored anywhere inside of "branch/"
+	filter.agnostic_pass("tree/artichokes");
+	filter.agnostic_fail("tree/branch/artichokes");
+	filter.agnostic_fail("tree/branch/inner/artichokes");
+	filter.agnostic_pass("tree/other/artichokes");
+
+	// "bananas/pears" should only be ignored at the root of "branch/"
+	filter.agnostic_pass("tree/bananas/pears");
+	filter.agnostic_fail("tree/branch/bananas/pears");
+	filter.agnostic_pass("tree/branch/inner/bananas/pears");
+	filter.agnostic_pass("tree/other/bananas/pears");
+}

crates/ignore-files/tests/global/first

@@ -0,0 +1 @@
+apples

crates/ignore-files/tests/global/second

@@ -0,0 +1 @@
+oranges

crates/ignore-files/tests/helpers/mod.rs

@@ -0,0 +1,159 @@
+use std::path::{Path, PathBuf};
+
+use ignore::{gitignore::Glob, Match};
+use ignore_files::{IgnoreFile, IgnoreFilter};
+
+pub mod ignore_tests {
+	pub use super::ig_file as file;
+	pub use super::ignore_filt as filt;
+	pub use super::Applies;
+	pub use super::PathHarness;
+}
+
+/// Get the drive letter of the current working directory.
+#[cfg(windows)]
+fn drive_root() -> String {
+	let path = std::fs::canonicalize(".").unwrap();
+
+	let Some(prefix) = path.components().next() else {
+		return r"C:\".into();
+	};
+
+	match prefix {
+		std::path::Component::Prefix(prefix_component) => prefix_component
+			.as_os_str()
+			.to_str()
+			.map(|p| p.to_owned() + r"\")
+			.unwrap_or(r"C:\".into()),
+		_ => r"C:\".into(),
+	}
+}
+
+fn normalize_path(path: &str) -> PathBuf {
+	#[cfg(windows)]
+	let path: &str = &String::from(path)
+		.strip_prefix("/")
+		.map_or(path.into(), |p| drive_root() + p);
+
+	let path: PathBuf = if Path::new(path).has_root() {
+		path.into()
+	} else {
+		std::fs::canonicalize(".").unwrap().join("tests").join(path)
+	};
+
+	dunce::simplified(&path).into()
+}
+
+pub trait PathHarness {
+	fn check_path(&self, path: &Path, is_dir: bool) -> Match<&Glob>;
+
+	fn path_pass(&self, path: &str, is_dir: bool, pass: bool) {
+		let full_path = &normalize_path(path);
+
+		tracing::info!(?path, ?is_dir, ?pass, "check");
+
+		let result = self.check_path(full_path, is_dir);
+
+		assert_eq!(
+			match result {
+				Match::None => true,
+				Match::Ignore(glob) => !glob.from().map_or(true, |f| full_path.starts_with(f)),
+				Match::Whitelist(_glob) => true,
+			},
+			pass,
+			"{} {:?} (expected {}) [result: {}]",
+			if is_dir { "dir" } else { "file" },
+			full_path,
+			if pass { "pass" } else { "fail" },
+			match result {
+				Match::None => String::from("None"),
+				Match::Ignore(glob) => format!(
+					"Ignore({})",
+					glob.from()
+						.map_or(String::from(""), |f| f.display().to_string())
+				),
+				Match::Whitelist(glob) => format!(
+					"Whitelist({})",
+					glob.from()
+						.map_or(String::from(""), |f| f.display().to_string())
+				),
+			},
+		);
+	}
+
+	fn file_does_pass(&self, path: &str) {
+		self.path_pass(path, false, true);
+	}
+
+	fn file_doesnt_pass(&self, path: &str) {
+		self.path_pass(path, false, false);
+	}
+
+	fn dir_does_pass(&self, path: &str) {
+		self.path_pass(path, true, true);
+	}
+
+	fn dir_doesnt_pass(&self, path: &str) {
+		self.path_pass(path, true, false);
+	}
+
+	fn agnostic_pass(&self, path: &str) {
+		self.file_does_pass(path);
+		self.dir_does_pass(path);
+	}
+
+	fn agnostic_fail(&self, path: &str) {
+		self.file_doesnt_pass(path);
+		self.dir_doesnt_pass(path);
+	}
+}
+
+impl PathHarness for IgnoreFilter {
+	fn check_path(&self, path: &Path, is_dir: bool) -> Match<&Glob> {
+		self.match_path(&path, is_dir)
+	}
+}
+
+fn tracing_init() {
+	use tracing_subscriber::{
+		fmt::{format::FmtSpan, Subscriber},
+		util::SubscriberInitExt,
+		EnvFilter,
+	};
+	Subscriber::builder()
+		.pretty()
+		.with_span_events(FmtSpan::NEW | FmtSpan::CLOSE)
+		.with_env_filter(EnvFilter::from_default_env())
+		.finish()
+		.try_init()
+		.ok();
+}
+
+pub async fn ignore_filt(origin: &str, ignore_files: &[IgnoreFile]) -> IgnoreFilter {
+	tracing_init();
+	let origin = normalize_path(origin);
+	IgnoreFilter::new(origin, ignore_files)
+		.await
+		.expect("making filterer")
+}
+
+pub fn ig_file(name: &str) -> IgnoreFile {
+	let path = normalize_path(name);
+	let parent: PathBuf = path.parent().unwrap_or(&path).into();
+	IgnoreFile {
+		path,
+		applies_in: Some(parent),
+		applies_to: None,
+	}
+}
+
+pub trait Applies {
+	fn applies_globally(self) -> Self;
+}
+
+impl Applies for IgnoreFile {
+	fn applies_globally(mut self) -> Self {
+		self.applies_in = None;
+		self
+	}
+}

crates/ignore-files/tests/tree/base

@@ -0,0 +1,3 @@
+/apples
+carrots
+pineapples/grapes

crates/ignore-files/tests/tree/branch/inner

@@ -0,0 +1,3 @@
+/cauliflowers
+artichokes
+bananas/pears