[isort] Fix syntax error after docstring ending with backslash (I002)

crates/ruff_linter/resources/test/fixtures/isort/required_imports/docstring_followed_by_continuation.py

@@ -0,0 +1,3 @@
+"""Hello, world!"""\
+
+x = 1; y = 2

crates/ruff_linter/src/importer/insertion.rs

@@ -56,13 +56,19 @@ impl<'a> Insertion<'a> {
         stylist: &Stylist,
     ) -> Insertion<'static> {
         // Skip over any docstrings.
-        let mut location = if let Some(location) = match_docstring_end(body) {
+        let mut location = if let Some(mut location) = match_docstring_end(body) {
             // If the first token after the docstring is a semicolon, insert after the semicolon as
             // an inline statement.
             if let Some(offset) = match_semicolon(locator.after(location)) {
                 return Insertion::inline(" ", location.add(offset).add(TextSize::of(';')), ";");
             }
 
+            // If the first token after the docstring is a continuation character (i.e. "\"), advance
+            // an additional row to prevent inserting in the same logical line.
+            if match_continuation(locator.after(location)).is_some() {
+                location = locator.full_line_end(location);
+            }
+
             // Otherwise, advance to the next row.
             locator.full_line_end(location)
         } else {
@@ -363,6 +369,16 @@ mod tests {
             Insertion::own_line("", TextSize::from(20), "\n")
         );
 
+        let contents = r#"
+"""Hello, world!"""\
+
+"#
+        .trim_start();
+        assert_eq!(
+            insert(contents)?,
+            Insertion::own_line("", TextSize::from(22), "\n")
+        );
+
         let contents = r"
 x = 1
 "

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

@@ -794,6 +794,7 @@ mod tests {
     #[test_case(Path::new("comments_and_newlines.py"))]
     #[test_case(Path::new("docstring.py"))]
     #[test_case(Path::new("docstring.pyi"))]
+    #[test_case(Path::new("docstring_followed_by_continuation.py"))]
     #[test_case(Path::new("docstring_only.py"))]
     #[test_case(Path::new("docstring_with_continuation.py"))]
     #[test_case(Path::new("docstring_with_semicolon.py"))]
@@ -828,6 +829,7 @@ mod tests {
     #[test_case(Path::new("comments_and_newlines.py"))]
     #[test_case(Path::new("docstring.py"))]
     #[test_case(Path::new("docstring.pyi"))]
+    #[test_case(Path::new("docstring_followed_by_continuation.py"))]
     #[test_case(Path::new("docstring_only.py"))]
     #[test_case(Path::new("docstring_with_continuation.py"))]
     #[test_case(Path::new("docstring_with_semicolon.py"))]

crates/ruff_linter/src/rules/isort/snapshots/ruff_linter__rules__isort__tests__required_import_docstring_followed_by_continuation.py.snap

@@ -0,0 +1,9 @@
+---
+source: crates/ruff_linter/src/rules/isort/mod.rs
+---
+docstring_followed_by_continuation.py:1:1: I002 [*] Missing required import: `from __future__ import annotations`
+ℹ Safe fix
+1 1 | """Hello, world!"""\
+2 2 | 
+  3 |+from __future__ import annotations
+3 4 | x = 1; y = 2

crates/ruff_linter/src/rules/isort/snapshots/ruff_linter__rules__isort__tests__required_import_with_alias_docstring_followed_by_continuation.py.snap

@@ -0,0 +1,9 @@
+---
+source: crates/ruff_linter/src/rules/isort/mod.rs
+---
+docstring_followed_by_continuation.py:1:1: I002 [*] Missing required import: `from __future__ import annotations as _annotations`
+ℹ Safe fix
+1 1 | """Hello, world!"""\
+2 2 | 
+  3 |+from __future__ import annotations as _annotations
+3 4 | x = 1; y = 2