feat(linter): no-barrel-file

closes #3069
closes #3215

Cargo.toml

@@ -92,6 +92,7 @@ oxc_traverse = { version = "0.13.0", path = "crates/oxc_traverse" }
 oxc_macros = { path = "crates/oxc_macros" }
 oxc_linter = { path = "crates/oxc_linter" }
 oxc_prettier = { path = "crates/oxc_prettier" }
+oxc_module_lexer = { path = "crates/oxc_module_lexer" }
 oxc_tasks_common = { path = "tasks/common" }
 
 napi = "2"

crates/oxc_ast/src/ast/js.rs

@@ -2660,6 +2660,16 @@ macro_rules! match_module_declaration {
 pub use match_module_declaration;
 
 impl<'a> ModuleDeclaration<'a> {
+ pub fn is_type(&self) -> bool {
+ match self {
+ Self::TSExportAssignment(_) | Self::TSNamespaceExportDeclaration(_) => true,
+ Self::ExportNamedDeclaration(decl) => decl.export_kind.is_type(),
+ Self::ExportAllDeclaration(decl) => decl.export_kind.is_type(),
+ Self::ImportDeclaration(decl) => decl.import_kind.is_type(),
+ Self::ExportDefaultDeclaration(_) => false,
+ }
+ }
+
  pub fn is_import(&self) -> bool {
  matches!(self, Self::ImportDeclaration(_))
  }

crates/oxc_linter/Cargo.toml

@@ -19,16 +19,16 @@ workspace = true
 doctest = false
 
 [dependencies]
-oxc_allocator = { workspace = true }
-oxc_parser = { workspace = true }
-oxc_span = { workspace = true }
-oxc_ast = { workspace = true }
-oxc_diagnostics = { workspace = true }
-oxc_macros = { workspace = true }
-oxc_semantic = { workspace = true }
-oxc_syntax = { workspace = true }
-oxc_codegen = { workspace = true }
-oxc_resolver = { workspace = true }
+oxc_allocator  = { workspace = true }
+oxc_parser  = { workspace = true }
+oxc_span  = { workspace = true }
+oxc_ast  = { workspace = true }
+oxc_diagnostics  = { workspace = true }
+oxc_macros  = { workspace = true }
+oxc_semantic  = { workspace = true }
+oxc_syntax  = { workspace = true }
+oxc_codegen  = { workspace = true }
+oxc_resolver  = { workspace = true }
 
 rayon = { workspace = true }
 lazy_static = { workspace = true } # used in oxc_macros

crates/oxc_linter/src/rules/oxc/no_barrel_file.rs

@@ -1,115 +1,144 @@
-use oxc_ast::AstKind;
-use oxc_diagnostics::OxcDiagnostic;
-
+use oxc_diagnostics::{LabeledSpan, OxcDiagnostic};
 use oxc_macros::declare_oxc_lint;
-use oxc_span::Span;
+use oxc_semantic::ModuleRecord;
 use oxc_syntax::module_graph_visitor::{ModuleGraphVisitorBuilder, VisitFoldWhile};
 
 use crate::{context::LintContext, rule::Rule};
 
-fn no_barrel_file_diagnostic(span: Span, x1: u32) -> OxcDiagnostic {
- OxcDiagnostic::warning(format!(
- "oxc(no-barrel-file): \
- Avoid barrel files, they slow down performance, \
- and cause large module graphs with modules that go unused.\n\
- Loading this barrel file results in importing {x1} modules."
- ))
- .with_help("For more information visit this link: <https://marvinh.dev/blog/speeding-up-javascript-ecosystem-part-7/>")
- .with_label(span)
+#[derive(Debug, Clone)]
+pub struct NoBarrelFile {
+ threshold: usize,
 }
 
-/// Minimum amount of exports to consider module as barrelfile
-const AMOUNT_OF_EXPORTS_TO_CONSIDER_MODULE_AS_BARREL: u8 = 3;
-
-/// <https://github.com/thepassle/eslint-plugin-barrel-files/blob/main/docs/rules/avoid-barrel-files.md>
-#[derive(Debug, Default, Clone)]
-pub struct NoBarrelFile;
+impl Default for NoBarrelFile {
+ fn default() -> Self {
+ Self { threshold: 100 }
+ }
+}
 
 declare_oxc_lint!(
  /// ### What it does
  ///
- /// Disallow the use of barrel files.
+ /// Disallow the use of barrel files where the file contains `export *` statements,
+ /// and the total number of modules exceed a threshold.
+ ///
+ /// The default threshold is 100;
+ ///
+ /// References:
+ ///
+ /// * <https://github.com/thepassle/eslint-plugin-barrel-files>
+ /// * <https://marvinh.dev/blog/speeding-up-javascript-ecosystem-part-7>
  ///
  /// ### Example
  ///
  /// Invalid:
+ ///
  /// ```javascript
- /// export { foo } from 'foo';
- /// export { bar } from 'bar';
- /// export { baz } from 'baz';
- /// export { qux } from 'qux';
+ /// export * from 'foo'; // where `foo` loads a subtree of 100 modules
+ /// import * as ns from 'foo'; // where `foo` loads a subtree of 100 modules
  /// ```
+ ///
  /// Valid:
+ ///
  /// ```javascript
- /// export type { foo } from './foo.js';
+ /// export { foo } from 'foo';
  /// ```
  NoBarrelFile,
- nursery
+ restriction
 );
 
 impl Rule for NoBarrelFile {
+ #[allow(clippy::cast_possible_truncation)]
+ fn from_configuration(value: serde_json::Value) -> Self {
+ Self {
+ threshold: value
+ .get(0)
+ .and_then(|config| config.get("threshold"))
+ .and_then(serde_json::Value::as_u64)
+ .map_or(NoBarrelFile::default().threshold, |n| n as usize),
+ }
+ }
+
  fn run_once(&self, ctx: &LintContext<'_>) {
  let semantic = ctx.semantic();
  let module_record = semantic.module_record();
- let Some(root) = semantic.nodes().root_node() else {
- // Return early if the semantic's root node isn't set.
- // It usually means we are running on an empty or invalid file.
+
+ if module_record.not_esm {
  return;
- };
-
- let AstKind::Program(program) = root.kind() else { unreachable!() };
-
- let declarations =
- program
- .body
- .iter()
- .fold(0, |acc, node| if node.is_declaration() { acc + 1 } else { acc });
- let exports =
- module_record.star_export_entries.len() + module_record.indirect_export_entries.len();
-
- if exports > declarations
- && exports > AMOUNT_OF_EXPORTS_TO_CONSIDER_MODULE_AS_BARREL as usize
- {
- let loaded_modules_count = ModuleGraphVisitorBuilder::default()
- .visit_fold(0, module_record, |acc, _, _| VisitFoldWhile::Next(acc + 1))
- .result;
- ctx.diagnostic(no_barrel_file_diagnostic(program.span, loaded_modules_count));
  }
+
+ let module_requests = module_record
+ .indirect_export_entries
+ .iter()
+ .chain(module_record.star_export_entries.iter())
+ .filter_map(|export_entry| {
+ if let Some(module_request) = &export_entry.module_request {
+ let import_name = &export_entry.import_name;
+ if import_name.is_all() || import_name.is_all_but_default() {
+ return Some(module_request);
+ }
+ }
+ None
+ })
+ .collect::<Vec<_>>();
+
+ let mut labels = vec![];
+ let mut total: usize = 0;
+
+ for module_request in module_requests {
+ if let Some(remote_module) = module_record.loaded_modules.get(module_request.name()) {
+ if let Some(count) = count_loaded_modules(remote_module.value()) {
+ total += count;
+ labels.push(LabeledSpan::new_with_span(
+ Some(format!("{count} modules")),
+ module_request.span(),
+ ));
+ }
+ };
+ }
+
+ if total >= self.threshold {
+ let diagnostic = OxcDiagnostic::warning(format!(
+ "oxc(no-barrel-file): Barrel file detected, {total} modules are loaded."
+ ))
+ .with_help(format!("Loading {total} modules is slow for runtimes and bundlers.\nSee also: <https://marvinh.dev/blog/speeding-up-javascript-ecosystem-part-7>."))
+ .with_labels(labels);
+ ctx.diagnostic(diagnostic);
+ }
+ }
+}
+
+fn count_loaded_modules(module_record: &ModuleRecord) -> Option<usize> {
+ if module_record.loaded_modules.is_empty() {
+ return None;
  }
+ Some(
+ ModuleGraphVisitorBuilder::default()
+ .visit_fold(0, module_record, |acc, _, _| VisitFoldWhile::Next(acc + 1))
+ .result,
+ )
 }
 
 #[test]
 fn test() {
  use crate::tester::Tester;
 
  let pass = vec![
- r#"export type * from "foo";"#,
- r#"export type { foo } from "foo";"#,
- r#"export type * from "foo";
- export type { bar } from "bar";"#,
- r#"import { foo, bar, baz } from "../feature";
- export { foo };
- export { bar };"#,
+ (r#"export type * from "foo";"#, None),
+ (r#"export type { foo } from "foo";"#, None),
+ (r#"export type * from "foo"; export type { bar } from "bar";"#, None),
+ (r#"import { foo, bar, baz } from "../import/export-star/models";"#, None),
  ];
 
- let fail = vec![
+ let settings = Some(serde_json::json!([{"threshold": 1}]));
+
+ let fail = vec![(
  r#"export * from "./deep/a.js";
  export * from "./deep/b.js";
  export * from "./deep/c.js";
  export * from "./deep/d.js";"#,
- r#"export { foo } from "foo";
- export { bar } from "bar";
- export { baz } from "baz";
- export { qux } from "qux";"#,
- r#"export { default as module1 } from "./module1";
- export { default as module2 } from "./module2";
- export { default as module3 } from "./module3";
- export { default as module4 } from "./module4";"#,
- r#"export { foo, type Foo } from "foo";
- export { bar, type Bar } from "bar";
- export { baz, type Baz } from "baz";
- export { qux, type Qux } from "qux";"#,
- ];
+ settings,
+ )];
 
  Tester::new(NoBarrelFile::NAME, pass, fail)
  .change_rule_path("index.ts")

crates/oxc_linter/src/snapshots/no_barrel_file.snap

@@ -2,42 +2,18 @@
 source: crates/oxc_linter/src/tester.rs
 expression: no_barrel_file
 ---
- ⚠ oxc(no-barrel-file): Avoid barrel files, they slow down performance, and cause large module graphs with modules that go unused.
- │ Loading this barrel file results in importing 4 modules.
- ╭─[index.ts:1:1]
- 1 │ ╭─▶ export * from "./deep/a.js";
- 2 │ │ export * from "./deep/b.js";
- 3 │ │ export * from "./deep/c.js";
- 4 │ ╰─▶ export * from "./deep/d.js";
+ ⚠ oxc(no-barrel-file): Barrel file detected, 6 modules are loaded.
+ ╭─[index.ts:1:15]
+ 1 │ export * from "./deep/a.js";
+ · ──────┬──────
+ · ╰── 3 modules
+ 2 │ export * from "./deep/b.js";
+ · ──────┬──────
+ · ╰── 2 modules
+ 3 │ export * from "./deep/c.js";
+ · ──────┬──────
+ · ╰── 1 modules
+ 4 │ export * from "./deep/d.js";
  ╰────
- help: For more information visit this link: <https://marvinh.dev/blog/speeding-up-javascript-ecosystem-part-7/>
-
- ⚠ oxc(no-barrel-file): Avoid barrel files, they slow down performance, and cause large module graphs with modules that go unused.
- │ Loading this barrel file results in importing 0 modules.
- ╭─[index.ts:1:1]
- 1 │ ╭─▶ export { foo } from "foo";
- 2 │ │ export { bar } from "bar";
- 3 │ │ export { baz } from "baz";
- 4 │ ╰─▶ export { qux } from "qux";
- ╰────
- help: For more information visit this link: <https://marvinh.dev/blog/speeding-up-javascript-ecosystem-part-7/>
-
- ⚠ oxc(no-barrel-file): Avoid barrel files, they slow down performance, and cause large module graphs with modules that go unused.
- │ Loading this barrel file results in importing 0 modules.
- ╭─[index.ts:1:1]
- 1 │ ╭─▶ export { default as module1 } from "./module1";
- 2 │ │ export { default as module2 } from "./module2";
- 3 │ │ export { default as module3 } from "./module3";
- 4 │ ╰─▶ export { default as module4 } from "./module4";
- ╰────
- help: For more information visit this link: <https://marvinh.dev/blog/speeding-up-javascript-ecosystem-part-7/>
-
- ⚠ oxc(no-barrel-file): Avoid barrel files, they slow down performance, and cause large module graphs with modules that go unused.
- │ Loading this barrel file results in importing 0 modules.
- ╭─[index.ts:1:1]
- 1 │ ╭─▶ export { foo, type Foo } from "foo";
- 2 │ │ export { bar, type Bar } from "bar";
- 3 │ │ export { baz, type Baz } from "baz";
- 4 │ ╰─▶ export { qux, type Qux } from "qux";
- ╰────
- help: For more information visit this link: <https://marvinh.dev/blog/speeding-up-javascript-ecosystem-part-7/>
+ help: Loading 6 modules is slow for runtimes and bundlers.
+ See also: <https://marvinh.dev/blog/speeding-up-javascript-ecosystem-part-7>.

crates/oxc_syntax/src/module_graph_visitor.rs

@@ -1,4 +1,6 @@
-use std::{collections::HashSet, marker::PhantomData, path::PathBuf, sync::Arc};
+use std::{marker::PhantomData, path::PathBuf, sync::Arc};
+
+use rustc_hash::FxHashSet;
 
 use oxc_span::CompactStr;
 
@@ -92,8 +94,11 @@ impl<'a, T> ModuleGraphVisitorBuilder<'a, T> {
  module: &ModuleRecord,
  visit: V,
  ) -> ModuleGraphVisitResult<T> {
- let mut visitor =
- ModuleGraphVisitor { traversed: HashSet::new(), depth: 0, max_depth: self.max_depth };
+ let mut visitor = ModuleGraphVisitor {
+ traversed: FxHashSet::default(),
+ depth: 0,
+ max_depth: self.max_depth,
+ };
  let filter = self.filter.unwrap_or_else(|| Box::new(|_, _| true));
  let event = self.event.unwrap_or_else(|| Box::new(|_, _, _| {}));
  let enter = self.enter.unwrap_or_else(|| Box::new(|_, _| {}));
@@ -120,7 +125,7 @@ impl<'a, T> Default for ModuleGraphVisitorBuilder<'a, T> {
 
 pub struct ModuleGraphVisitResult<T> {
  pub result: T,
- pub traversed: HashSet<PathBuf>,
+ pub traversed: FxHashSet<PathBuf>,
  pub max_depth: u32,
 }
 
@@ -132,7 +137,7 @@ impl<T> ModuleGraphVisitResult<T> {
 
 #[derive(Debug)]
 struct ModuleGraphVisitor {
- traversed: HashSet<PathBuf>,
+ traversed: FxHashSet<PathBuf>,
  depth: u32,
  max_depth: u32,
 }