Implement Pylint's yield-inside-async-function rule (PLE1700) (#4668

)

crates/ruff/resources/test/fixtures/pylint/yield_from_in_async_function.py

@@ -0,0 +1,7 @@
+async def success():
+    yield 42
+
+
+async def fail():
+    l = (1, 2, 3)
+    yield from l

crates/ruff/src/checkers/ast/mod.rs

@@ -3077,13 +3077,16 @@ where
                     pylint::rules::yield_in_init(self, expr);
                 }
             }
-            Expr::YieldFrom(_) => {
+            Expr::YieldFrom(yield_from) => {
                 if self.enabled(Rule::YieldOutsideFunction) {
                     pyflakes::rules::yield_outside_function(self, expr);
                 }
                 if self.enabled(Rule::YieldInInit) {
                     pylint::rules::yield_in_init(self, expr);
                 }
+                if self.enabled(Rule::YieldFromInAsyncFunction) {
+                    pylint::rules::yield_from_in_async_function(self, yield_from);
+                }
             }
             Expr::Await(_) => {
                 if self.enabled(Rule::YieldOutsideFunction) {

crates/ruff/src/codes.rs

@@ -165,6 +165,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Pylint, "E1307") => (RuleGroup::Unspecified, Rule::BadStringFormatType),
         (Pylint, "E1310") => (RuleGroup::Unspecified, Rule::BadStrStripCall),
         (Pylint, "E1507") => (RuleGroup::Unspecified, Rule::InvalidEnvvarValue),
+        (Pylint, "E1700") => (RuleGroup::Unspecified, Rule::YieldFromInAsyncFunction),
         (Pylint, "E2502") => (RuleGroup::Unspecified, Rule::BidirectionalUnicode),
         (Pylint, "E2510") => (RuleGroup::Unspecified, Rule::InvalidCharacterBackspace),
         (Pylint, "E2512") => (RuleGroup::Unspecified, Rule::InvalidCharacterSub),

crates/ruff/src/registry.rs

@@ -117,6 +117,7 @@ ruff_macros::register_rules!(
     // pylint
     rules::pylint::rules::AssertOnStringLiteral,
     rules::pylint::rules::UselessReturn,
+    rules::pylint::rules::YieldFromInAsyncFunction,
     rules::pylint::rules::YieldInInit,
     rules::pylint::rules::InvalidAllObject,
     rules::pylint::rules::InvalidAllFormat,

crates/ruff/src/rules/pylint/mod.rs

@@ -73,6 +73,7 @@ mod tests {
     #[test_case(Rule::UselessElseOnLoop, Path::new("useless_else_on_loop.py"); "PLW0120")]
     #[test_case(Rule::UselessImportAlias, Path::new("import_aliasing.py"); "PLC0414")]
     #[test_case(Rule::UselessReturn, Path::new("useless_return.py"); "PLR1711")]
+    #[test_case(Rule::YieldFromInAsyncFunction, Path::new("yield_from_in_async_function.py"); "PLE1700")]
     #[test_case(Rule::YieldInInit, Path::new("yield_in_init.py"); "PLE0100")]
     #[test_case(Rule::NestedMinMax, Path::new("nested_min_max.py"); "PLW3301")]
     fn rules(rule_code: Rule, path: &Path) -> Result<()> {

crates/ruff/src/rules/pylint/rules/mod.rs

@@ -48,6 +48,9 @@ pub(crate) use unnecessary_direct_lambda_call::{
 pub(crate) use useless_else_on_loop::{useless_else_on_loop, UselessElseOnLoop};
 pub(crate) use useless_import_alias::{useless_import_alias, UselessImportAlias};
 pub(crate) use useless_return::{useless_return, UselessReturn};
+pub(crate) use yield_from_in_async_function::{
+    yield_from_in_async_function, YieldFromInAsyncFunction,
+};
 pub(crate) use yield_in_init::{yield_in_init, YieldInInit};
 
 mod assert_on_string_literal;
@@ -91,4 +94,5 @@ mod unnecessary_direct_lambda_call;
 mod useless_else_on_loop;
 mod useless_import_alias;
 mod useless_return;
+mod yield_from_in_async_function;
 mod yield_in_init;

crates/ruff/src/rules/pylint/rules/yield_from_in_async_function.rs

@@ -0,0 +1,47 @@
+use rustpython_parser::ast::{ExprYieldFrom, Ranged};
+
+use ruff_diagnostics::{Diagnostic, Violation};
+use ruff_macros::{derive_message_formats, violation};
+
+use crate::checkers::ast::Checker;
+
+/// ## What it does
+/// Checks for uses of `yield from` in async functions.
+///
+/// ## Why is this bad?
+/// Python doesn't support the use of `yield from` in async functions, and will
+/// raise a `SyntaxError` in such cases.
+///
+/// Instead, considering refactoring the code to use an `async for` loop instead.
+///
+/// ## Example
+/// ```python
+/// async def numbers():
+///     yield from [1, 2, 3, 4, 5]
+/// ```
+///
+/// Use instead:
+/// ```python
+/// async def numbers():
+///   async for number in [1, 2, 3, 4, 5]:
+///        yield number
+/// ```
+#[violation]
+pub struct YieldFromInAsyncFunction;
+
+impl Violation for YieldFromInAsyncFunction {
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        format!("`yield from` statement in async function; use `async for` instead")
+    }
+}
+
+/// PLE1700
+pub(crate) fn yield_from_in_async_function(checker: &mut Checker, expr: &ExprYieldFrom) {
+    let scope = checker.semantic_model().scope();
+    if scope.kind.is_async_function() {
+        checker
+            .diagnostics
+            .push(Diagnostic::new(YieldFromInAsyncFunction, expr.range()));
+    }
+}

crates/ruff/src/rules/pylint/snapshots/ruff__rules__pylint__tests__PLE1700_yield_from_in_async_function.py.snap

@@ -0,0 +1,12 @@
+---
+source: crates/ruff/src/rules/pylint/mod.rs
+---
+yield_from_in_async_function.py:7:5: PLE1700 `yield from` statement in async function; use `async for` instead
+  |
+7 | async def fail():
+8 |     l = (1, 2, 3)
+9 |     yield from l
+  |     ^^^^^^^^^^^^ PLE1700
+  |
+
+