Implement exempt-modules setting from flake8-type-checking (#2230)

README.md

@@ -3108,6 +3108,24 @@ and can be circumvented via `eval` or `importlib`.
 
 ### `flake8-type-checking`
 
+#### [`exempt-modules`](#exempt-modules)
+
+Exempt certain modules from needing to be moved into type-checking
+blocks.
+
+**Default value**: `[]`
+
+**Type**: `Vec<String>`
+
+**Example usage**:
+
+```toml
+[tool.ruff.flake8-type-checking]
+exempt-modules = ["typing_extensions"]
+```
+
+---
+
 #### [`strict`](#strict)
 
 Enforce TC001, TC002, and TC003 rules even when valid runtime imports

resources/test/fixtures/flake8_type_checking/exempt_modules.py

@@ -0,0 +1,16 @@
+def f():
+    import pandas as pd
+
+    x: pd.DataFrame
+
+
+def f():
+    import pandas.core.frame as pd
+
+    x: pd.DataFrame
+
+
+def f():
+    import flask
+
+    x: flask

ruff.schema.json

@@ -836,6 +836,16 @@
     "Flake8TypeCheckingOptions": {
       "type": "object",
       "properties": {
+        "exempt-modules": {
+          "description": "Exempt certain modules from needing to be moved into type-checking blocks.",
+          "type": [
+            "array",
+            "null"
+          ],
+          "items": {
+            "type": "string"
+          }
+        },
         "strict": {
           "description": "Enforce TC001, TC002, and TC003 rules even when valid runtime imports are present for the same module. See: https://github.com/snok/flake8-type-checking#strict.",
           "type": [

src/rules/flake8_type_checking/mod.rs

@@ -47,7 +47,28 @@ mod tests {
                 .join(path)
                 .as_path(),
             &settings::Settings {
-                flake8_type_checking: super::settings::Settings { strict: true },
+                flake8_type_checking: super::settings::Settings {
+                    strict: true,
+                    ..Default::default()
+                },
+                ..settings::Settings::for_rule(rule_code)
+            },
+        )?;
+        assert_yaml_snapshot!(diagnostics);
+        Ok(())
+    }
+
+    #[test_case(Rule::TypingOnlyThirdPartyImport, Path::new("exempt_modules.py"); "exempt_modules")]
+    fn exempt_modules(rule_code: Rule, path: &Path) -> Result<()> {
+        let diagnostics = test_path(
+            Path::new("./resources/test/fixtures/flake8_type_checking")
+                .join(path)
+                .as_path(),
+            &settings::Settings {
+                flake8_type_checking: super::settings::Settings {
+                    exempt_modules: vec!["pandas".to_string()],
+                    ..Default::default()
+                },
                 ..settings::Settings::for_rule(rule_code)
             },
         )?;

src/rules/flake8_type_checking/rules/typing_only_runtime_import.rs

@@ -95,6 +95,22 @@ fn is_implicit_import(this: &Binding, that: &Binding) -> bool {
     }
 }
 
+/// Return `true` if `name` is exempt from typing-only enforcement.
+fn is_exempt(name: &str, exempt_modules: &[&str]) -> bool {
+    let mut name = name;
+    loop {
+        if exempt_modules.contains(&name) {
+            return true;
+        }
+        match name.rfind('.') {
+            Some(idx) => {
+                name = &name[..idx];
+            }
+            None => return false,
+        }
+    }
+}
+
 /// TCH001
 pub fn typing_only_runtime_import(
     binding: &Binding,
@@ -120,6 +136,18 @@ pub fn typing_only_runtime_import(
         _ => return None,
     };
 
+    if is_exempt(
+        full_name,
+        &settings
+            .flake8_type_checking
+            .exempt_modules
+            .iter()
+            .map(String::as_str)
+            .collect::<Vec<_>>(),
+    ) {
+        return None;
+    }
+
     let defined_in_type_checking = blocks
         .iter()
         .any(|block| Range::from_located(block).contains(&binding.range));

src/rules/flake8_type_checking/settings.rs

@@ -24,17 +24,29 @@ pub struct Options {
     /// are present for the same module.
     /// See: https://github.com/snok/flake8-type-checking#strict.
     pub strict: Option<bool>,
+    #[option(
+        default = "[]",
+        value_type = "Vec<String>",
+        example = r#"
+            exempt-modules = ["typing_extensions"]
+        "#
+    )]
+    /// Exempt certain modules from needing to be moved into type-checking
+    /// blocks.
+    pub exempt_modules: Option<Vec<String>>,
 }
 
 #[derive(Debug, Hash, Default)]
 pub struct Settings {
     pub strict: bool,
+    pub exempt_modules: Vec<String>,
 }
 
 impl From<Options> for Settings {
     fn from(options: Options) -> Self {
         Self {
             strict: options.strict.unwrap_or_default(),
+            exempt_modules: options.exempt_modules.unwrap_or_default(),
         }
     }
 }
@@ -43,6 +55,7 @@ impl From<Settings> for Options {
     fn from(settings: Settings) -> Self {
         Self {
             strict: Some(settings.strict),
+            exempt_modules: Some(settings.exempt_modules),
         }
     }
 }

src/rules/flake8_type_checking/snapshots/ruff__rules__flake8_type_checking__tests__exempt_modules.snap

@@ -0,0 +1,16 @@
+---
+source: src/rules/flake8_type_checking/mod.rs
+expression: diagnostics
+---
+- kind:
+    TypingOnlyThirdPartyImport:
+      full_name: flask
+  location:
+    row: 14
+    column: 11
+  end_location:
+    row: 14
+    column: 16
+  fix: ~
+  parent: ~
+