Add support for namespace packages (#1859)

Closes #1817.

README.md

@@ -2154,6 +2154,25 @@ line-length = 120
 
 ---
 
+#### [`namespace-packages`](#namespace-packages)
+
+Mark the specified directories as namespace packages. For the purpose of
+module resolution, Ruff will treat those directories as if they
+contained an `__init__.py` file.
+
+**Default value**: `[]`
+
+**Type**: `Vec<PathBuf>`
+
+**Example usage**:
+
+```toml
+[tool.ruff]
+namespace-packages = ["airflow/providers"]
+```
+
+---
+
 #### [`per-file-ignores`](#per-file-ignores)
 
 A list of mappings from file pattern to rule codes or prefixes to

flake8_to_ruff/src/converter.rs

@@ -423,6 +423,7 @@ mod tests {
             ignore: Some(vec![]),
             ignore_init_module_imports: None,
             line_length: None,
+            namespace_packages: None,
             per_file_ignores: None,
             required_version: None,
             respect_gitignore: None,
@@ -488,6 +489,7 @@ mod tests {
             ignore: Some(vec![]),
             ignore_init_module_imports: None,
             line_length: Some(100),
+            namespace_packages: None,
             per_file_ignores: None,
             required_version: None,
             respect_gitignore: None,
@@ -553,6 +555,7 @@ mod tests {
             ignore: Some(vec![]),
             ignore_init_module_imports: None,
             line_length: Some(100),
+            namespace_packages: None,
             per_file_ignores: None,
             required_version: None,
             respect_gitignore: None,
@@ -618,6 +621,7 @@ mod tests {
             ignore: Some(vec![]),
             ignore_init_module_imports: None,
             line_length: None,
+            namespace_packages: None,
             per_file_ignores: None,
             required_version: None,
             respect_gitignore: None,
@@ -683,6 +687,7 @@ mod tests {
             ignore: Some(vec![]),
             ignore_init_module_imports: None,
             line_length: None,
+            namespace_packages: None,
             per_file_ignores: None,
             required_version: None,
             respect_gitignore: None,
@@ -756,6 +761,7 @@ mod tests {
             ignore: Some(vec![]),
             ignore_init_module_imports: None,
             line_length: None,
+            namespace_packages: None,
             per_file_ignores: None,
             required_version: None,
             respect_gitignore: None,
@@ -824,6 +830,7 @@ mod tests {
             ignore: Some(vec![]),
             ignore_init_module_imports: None,
             line_length: None,
+            namespace_packages: None,
             per_file_ignores: None,
             required_version: None,
             respect_gitignore: None,

ruff.schema.json

@@ -285,6 +285,16 @@
         }
       ]
     },
+    "namespace-packages": {
+      "description": "Mark the specified directories as namespace packages. For the purpose of module resolution, Ruff will treat those directories as if they contained an `__init__.py` file.",
+      "type": [
+        "array",
+        "null"
+      ],
+      "items": {
+        "type": "string"
+      }
+    },
     "pep8-naming": {
       "description": "Options for the `pep8-naming` plugin.",
       "anyOf": [

ruff_cli/src/commands.rs

@@ -83,6 +83,8 @@ pub fn run(
             .flatten()
             .map(ignore::DirEntry::path)
             .collect::<Vec<_>>(),
+        &resolver,
+        pyproject_strategy,
     );
 
     let start = Instant::now();
@@ -169,7 +171,7 @@ pub fn run_stdin(
     };
     let package_root = filename
         .and_then(Path::parent)
-        .and_then(packaging::detect_package_root);
+        .and_then(|path| packaging::detect_package_root(path, &settings.namespace_packages));
     let stdin = read_from_stdin()?;
     let mut diagnostics = lint_stdin(filename, package_root, &stdin, settings, autofix)?;
     diagnostics.messages.sort_unstable();

src/lib_native.rs

@@ -51,7 +51,7 @@ pub fn check(path: &Path, contents: &str, autofix: bool) -> Result<Vec<Diagnosti
     // Generate diagnostics.
     let diagnostics = check_path(
         path,
-        packaging::detect_package_root(path),
+        packaging::detect_package_root(path, &settings.namespace_packages),
         contents,
         tokens,
         &locator,

src/lib_wasm.rs

@@ -105,14 +105,15 @@ pub fn defaultSettings() -> Result<JsValue, JsValue> {
         force_exclude: None,
         format: None,
         ignore_init_module_imports: None,
+        namespace_packages: None,
         per_file_ignores: None,
         required_version: None,
         respect_gitignore: None,
         show_source: None,
         src: None,
-        unfixable: None,
-        typing_modules: None,
         task_tags: None,
+        typing_modules: None,
+        unfixable: None,
         update_check: None,
         // Use default options for all plugins.
         flake8_annotations: Some(flake8_annotations::settings::Settings::default().into()),

src/packaging.rs

@@ -1,9 +1,11 @@
 //! Detect Python package roots and file associations.
 
-use std::path::Path;
+use std::path::{Path, PathBuf};
 
 use rustc_hash::FxHashMap;
 
+use crate::resolver::{PyprojectDiscovery, Resolver};
+
 // If we have a Python package layout like:
 // - root/
 //   - foo/
@@ -27,15 +29,21 @@ use rustc_hash::FxHashMap;
 
 /// Return `true` if the directory at the given `Path` appears to be a Python
 /// package.
-pub fn is_package(path: &Path) -> bool {
+pub fn is_package(path: &Path, namespace_packages: &[PathBuf]) -> bool {
     path.join("__init__.py").is_file()
+        || namespace_packages
+            .iter()
+            .any(|namespace_package| namespace_package == path)
 }
 
 /// Return the package root for the given Python file.
-pub fn detect_package_root(path: &Path) -> Option<&Path> {
+pub fn detect_package_root<'a>(
+    path: &'a Path,
+    namespace_packages: &'a [PathBuf],
+) -> Option<&'a Path> {
     let mut current = None;
     for parent in path.ancestors() {
-        if !is_package(parent) {
+        if !is_package(parent, namespace_packages) {
             return current;
         }
         current = Some(parent);
@@ -46,21 +54,23 @@ pub fn detect_package_root(path: &Path) -> Option<&Path> {
 /// A wrapper around `is_package` to cache filesystem lookups.
 fn is_package_with_cache<'a>(
     path: &'a Path,
+    namespace_packages: &'a [PathBuf],
     package_cache: &mut FxHashMap<&'a Path, bool>,
 ) -> bool {
     *package_cache
         .entry(path)
-        .or_insert_with(|| is_package(path))
+        .or_insert_with(|| is_package(path, namespace_packages))
 }
 
 /// A wrapper around `detect_package_root` to cache filesystem lookups.
 fn detect_package_root_with_cache<'a>(
     path: &'a Path,
+    namespace_packages: &'a [PathBuf],
     package_cache: &mut FxHashMap<&'a Path, bool>,
 ) -> Option<&'a Path> {
     let mut current = None;
     for parent in path.ancestors() {
-        if !is_package_with_cache(parent, package_cache) {
+        if !is_package_with_cache(parent, namespace_packages, package_cache) {
             return current;
         }
         current = Some(parent);
@@ -69,7 +79,11 @@ fn detect_package_root_with_cache<'a>(
 }
 
 /// Return a mapping from Python file to its package root.
-pub fn detect_package_roots<'a>(files: &[&'a Path]) -> FxHashMap<&'a Path, Option<&'a Path>> {
+pub fn detect_package_roots<'a>(
+    files: &[&'a Path],
+    resolver: &'a Resolver,
+    pyproject_strategy: &'a PyprojectDiscovery,
+) -> FxHashMap<&'a Path, Option<&'a Path>> {
     // Pre-populate the module cache, since the list of files could (but isn't
     // required to) contain some `__init__.py` files.
     let mut package_cache: FxHashMap<&Path, bool> = FxHashMap::default();
@@ -84,13 +98,16 @@ pub fn detect_package_roots<'a>(files: &[&'a Path]) -> FxHashMap<&'a Path, Optio
     // Search for the package root for each file.
     let mut package_roots: FxHashMap<&Path, Option<&Path>> = FxHashMap::default();
     for file in files {
+        let namespace_packages = &resolver
+            .resolve(file, pyproject_strategy)
+            .namespace_packages;
         if let Some(package) = file.parent() {
             if package_roots.contains_key(package) {
                 continue;
             }
             package_roots.insert(
                 package,
-                detect_package_root_with_cache(package, &mut package_cache),
+                detect_package_root_with_cache(package, namespace_packages, &mut package_cache),
             );
         }
     }
@@ -111,6 +128,7 @@ mod tests {
                 PathBuf::from(env!("CARGO_MANIFEST_DIR"))
                     .join("resources/test/package/src/package")
                     .as_path(),
+                &[],
             ),
             Some(
                 PathBuf::from(env!("CARGO_MANIFEST_DIR"))
@@ -124,6 +142,7 @@ mod tests {
                 PathBuf::from(env!("CARGO_MANIFEST_DIR"))
                     .join("resources/test/project/python_modules/core/core")
                     .as_path(),
+                &[],
             ),
             Some(
                 PathBuf::from(env!("CARGO_MANIFEST_DIR"))
@@ -137,6 +156,7 @@ mod tests {
                 PathBuf::from(env!("CARGO_MANIFEST_DIR"))
                     .join("resources/test/project/examples/docs/docs/concepts")
                     .as_path(),
+                &[],
             ),
             Some(
                 PathBuf::from(env!("CARGO_MANIFEST_DIR"))
@@ -150,6 +170,7 @@ mod tests {
                 PathBuf::from(env!("CARGO_MANIFEST_DIR"))
                     .join("setup.py")
                     .as_path(),
+                &[],
             ),
             None,
         );

src/settings/configuration.rs

@@ -44,6 +44,7 @@ pub struct Configuration {
     pub ignore: Option<Vec<RuleCodePrefix>>,
     pub ignore_init_module_imports: Option<bool>,
     pub line_length: Option<usize>,
+    pub namespace_packages: Option<Vec<PathBuf>>,
     pub per_file_ignores: Option<Vec<PerFileIgnore>>,
     pub required_version: Option<Version>,
     pub respect_gitignore: Option<bool>,
@@ -135,6 +136,10 @@ impl Configuration {
             ignore: options.ignore,
             ignore_init_module_imports: options.ignore_init_module_imports,
             line_length: options.line_length,
+            namespace_packages: options
+                .namespace_packages
+                .map(|namespace_package| resolve_src(&namespace_package, project_root))
+                .transpose()?,
             per_file_ignores: options.per_file_ignores.map(|per_file_ignores| {
                 per_file_ignores
                     .into_iter()
@@ -211,6 +216,7 @@ impl Configuration {
                 .ignore_init_module_imports
                 .or(config.ignore_init_module_imports),
             line_length: self.line_length.or(config.line_length),
+            namespace_packages: self.namespace_packages.or(config.namespace_packages),
             per_file_ignores: self.per_file_ignores.or(config.per_file_ignores),
             required_version: self.required_version.or(config.required_version),
             respect_gitignore: self.respect_gitignore.or(config.respect_gitignore),

src/settings/mod.rs

@@ -55,6 +55,7 @@ pub struct Settings {
     pub format: SerializationFormat,
     pub ignore_init_module_imports: bool,
     pub line_length: usize,
+    pub namespace_packages: Vec<PathBuf>,
     pub per_file_ignores: Vec<(GlobMatcher, GlobMatcher, FxHashSet<RuleCode>)>,
     pub required_version: Option<Version>,
     pub respect_gitignore: bool,
@@ -169,6 +170,7 @@ impl Settings {
             force_exclude: config.force_exclude.unwrap_or(false),
             ignore_init_module_imports: config.ignore_init_module_imports.unwrap_or_default(),
             line_length: config.line_length.unwrap_or(88),
+            namespace_packages: config.namespace_packages.unwrap_or_default(),
             per_file_ignores: resolve_per_file_ignores(
                 config.per_file_ignores.unwrap_or_default(),
             )?,
@@ -235,6 +237,7 @@ impl Settings {
             format: SerializationFormat::Text,
             ignore_init_module_imports: false,
             line_length: 88,
+            namespace_packages: vec![],
             per_file_ignores: vec![],
             required_version: None,
             respect_gitignore: true,
@@ -279,6 +282,7 @@ impl Settings {
             format: SerializationFormat::Text,
             ignore_init_module_imports: false,
             line_length: 88,
+            namespace_packages: vec![],
             per_file_ignores: vec![],
             required_version: None,
             respect_gitignore: true,

src/settings/options.rs

@@ -352,6 +352,17 @@ pub struct Options {
     /// packages in that directory. User home directory and environment
     /// variables will also be expanded.
     pub src: Option<Vec<String>>,
+    #[option(
+        default = r#"[]"#,
+        value_type = "Vec<PathBuf>",
+        example = r#"
+            namespace-packages = ["airflow/providers"]
+        "#
+    )]
+    /// Mark the specified directories as namespace packages. For the purpose of
+    /// module resolution, Ruff will treat those directories as if they
+    /// contained an `__init__.py` file.
+    pub namespace_packages: Option<Vec<String>>,
     #[option(
         default = r#""py310""#,
         value_type = "PythonVersion",

src/settings/pyproject.rs

@@ -181,6 +181,7 @@ mod tests {
                     ignore: None,
                     ignore_init_module_imports: None,
                     line_length: None,
+                    namespace_packages: None,
                     per_file_ignores: None,
                     required_version: None,
                     respect_gitignore: None,
@@ -239,6 +240,7 @@ line-length = 79
                     ignore: None,
                     ignore_init_module_imports: None,
                     line_length: Some(79),
+                    namespace_packages: None,
                     per_file_ignores: None,
                     respect_gitignore: None,
                     required_version: None,
@@ -299,6 +301,7 @@ exclude = ["foo.py"]
                     ignore: None,
                     ignore_init_module_imports: None,
                     line_length: None,
+                    namespace_packages: None,
                     per_file_ignores: None,
                     required_version: None,
                     respect_gitignore: None,
@@ -358,6 +361,7 @@ select = ["E501"]
                     ignore: None,
                     ignore_init_module_imports: None,
                     line_length: None,
+                    namespace_packages: None,
                     per_file_ignores: None,
                     required_version: None,
                     respect_gitignore: None,
@@ -418,6 +422,7 @@ ignore = ["E501"]
                     ignore: Some(vec![RuleCodePrefix::E501]),
                     ignore_init_module_imports: None,
                     line_length: None,
+                    namespace_packages: None,
                     per_file_ignores: None,
                     required_version: None,
                     respect_gitignore: None,
@@ -515,6 +520,7 @@ other-attribute = 1
                 fixable: None,
                 format: None,
                 force_exclude: None,
+                namespace_packages: None,
                 unfixable: None,
                 typing_modules: None,
                 task_tags: None,