Fix await-outside-async to allow await at the top-level scope of a notebook

crates/ruff_linter/resources/test/fixtures/pylint/await_outside_async.ipynb

@@ -0,0 +1,42 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import asyncio\n",
+    "\n",
+    "await asyncio.sleep(1)  # This is okay\n",
+    "\n",
+    "if True:\n",
+    "    await asyncio.sleep(1)  # This is okay\n",
+    "\n",
+    "def foo():\n",
+    "    await asyncio.sleep(1)  # # [await-outside-async]"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "base",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.8.5"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 2
+}

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

@@ -27,6 +27,7 @@ mod tests {
     )]
     #[test_case(Rule::AssertOnStringLiteral, Path::new("assert_on_string_literal.py"))]
     #[test_case(Rule::AwaitOutsideAsync, Path::new("await_outside_async.py"))]
+    #[test_case(Rule::AwaitOutsideAsync, Path::new("await_outside_async.ipynb"))]
     #[test_case(Rule::BadOpenMode, Path::new("bad_open_mode.py"))]
     #[test_case(
         Rule::BadStringFormatCharacter,

crates/ruff_linter/src/rules/pylint/rules/await_outside_async.rs

@@ -11,6 +11,9 @@ use crate::checkers::ast::Checker;
 /// ## Why is this bad?
 /// Using `await` outside an `async` function is a syntax error.
 ///
+/// As an exception, `await` is allowed at the top level of a Jupyter notebook
+/// (see: [autoawait]).
+///
 /// ## Example
 /// ```python
 /// import asyncio
@@ -32,6 +35,8 @@ use crate::checkers::ast::Checker;
 /// ## References
 /// - [Python documentation: Await expression](https://docs.python.org/3/reference/expressions.html#await)
 /// - [PEP 492: Await Expression](https://peps.python.org/pep-0492/#await-expression)
+///
+/// [autoawait]: https://ipython.readthedocs.io/en/stable/interactive/autoawait.html
 #[violation]
 pub struct AwaitOutsideAsync;
 
@@ -49,6 +54,12 @@ pub(crate) fn await_outside_async<T: Ranged>(checker: &mut Checker, node: T) {
         return;
     }
 
+    // `await` is allowed at the top level of a Jupyter notebook.
+    // See: https://ipython.readthedocs.io/en/stable/interactive/autoawait.html.
+    if checker.semantic().current_scope().kind.is_module() && checker.source_type.is_ipynb() {
+        return;
+    }
+
     // Generators are evaluated lazily, so you can use `await` in them. For example:
     // ```python
     // # This is valid

crates/ruff_linter/src/rules/pylint/snapshots/ruff_linter__rules__pylint__tests__PLE1142_await_outside_async.ipynb.snap

@@ -0,0 +1,11 @@
+---
+source: crates/ruff_linter/src/rules/pylint/mod.rs
+assertion_line: 236
+snapshot_kind: text
+---
+await_outside_async.ipynb:9:5: PLE1142 `await` should be used within an async function
+  |
+8 | def foo():
+9 |     await asyncio.sleep(1)  # # [await-outside-async]
+  |     ^^^^^^^^^^^^^^^^^^^^^^ PLE1142
+  |