From f4c6ff3f68ace5160c6b7bbdd734bec1885541a9 Mon Sep 17 00:00:00 2001
From: Victor Hugo Gomes <labatata101@gmail.com>
Date: Mon, 23 Jun 2025 11:15:53 -0300
Subject: [PATCH] [`pylint`] Fix `PLC2801` autofix creating a syntax error
 (#18857)

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## Summary
This PR fixes `PLC2801` autofix creating a syntax error due to lack of
padding if it is directly after a keyword.

Fixes https://github.com/astral-sh/ruff/issues/18813
<!-- What's the purpose of the change? What does it do, and why? -->

## Test Plan
Add regression test
<!-- How was it tested? -->
---
 .../pylint/unnecessary_dunder_call.py         |  3 +++
 .../pylint/rules/unnecessary_dunder_call.rs   |  3 ++-
 ...s__PLC2801_unnecessary_dunder_call.py.snap | 20 +++++++++++++++++++
 3 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/crates/ruff_linter/resources/test/fixtures/pylint/unnecessary_dunder_call.py b/crates/ruff_linter/resources/test/fixtures/pylint/unnecessary_dunder_call.py
index 2f46174fd3..8bdb4d6605 100644
--- a/crates/ruff_linter/resources/test/fixtures/pylint/unnecessary_dunder_call.py
+++ b/crates/ruff_linter/resources/test/fixtures/pylint/unnecessary_dunder_call.py
@@ -129,3 +129,6 @@ blah = dict[{"a": 1}.__delitem__("a")]  # OK
 
 # https://github.com/astral-sh/ruff/issues/14597
 assert "abc".__str__() == "abc"
+
+# https://github.com/astral-sh/ruff/issues/18813
+three = 1 if 1 else(3.0).__str__()
diff --git a/crates/ruff_linter/src/rules/pylint/rules/unnecessary_dunder_call.rs b/crates/ruff_linter/src/rules/pylint/rules/unnecessary_dunder_call.rs
index a5b9c61aa9..62f69fad7b 100644
--- a/crates/ruff_linter/src/rules/pylint/rules/unnecessary_dunder_call.rs
+++ b/crates/ruff_linter/src/rules/pylint/rules/unnecessary_dunder_call.rs
@@ -4,6 +4,7 @@ use ruff_python_semantic::SemanticModel;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
+use crate::fix::edits;
 use crate::rules::pylint::helpers::is_known_dunder_method;
 use crate::{Edit, Fix, FixAvailability, Violation};
 use ruff_python_ast::PythonVersion;
@@ -232,7 +233,7 @@ pub(crate) fn unnecessary_dunder_call(checker: &Checker, call: &ast::ExprCall) {
         }
 
         diagnostic.set_fix(Fix::unsafe_edit(Edit::range_replacement(
-            fixed,
+            edits::pad(fixed, call.range(), checker.locator()),
             call.range(),
         )));
     }
diff --git a/crates/ruff_linter/src/rules/pylint/snapshots/ruff_linter__rules__pylint__tests__PLC2801_unnecessary_dunder_call.py.snap b/crates/ruff_linter/src/rules/pylint/snapshots/ruff_linter__rules__pylint__tests__PLC2801_unnecessary_dunder_call.py.snap
index 4d897e73d9..971cc51c39 100644
--- a/crates/ruff_linter/src/rules/pylint/snapshots/ruff_linter__rules__pylint__tests__PLC2801_unnecessary_dunder_call.py.snap
+++ b/crates/ruff_linter/src/rules/pylint/snapshots/ruff_linter__rules__pylint__tests__PLC2801_unnecessary_dunder_call.py.snap
@@ -1193,6 +1193,8 @@ unnecessary_dunder_call.py:131:8: PLC2801 [*] Unnecessary dunder call to `__str_
 130 | # https://github.com/astral-sh/ruff/issues/14597
 131 | assert "abc".__str__() == "abc"
     |        ^^^^^^^^^^^^^^^ PLC2801
+132 |
+133 | # https://github.com/astral-sh/ruff/issues/18813
     |
     = help: Use `str()` builtin
 
@@ -1202,3 +1204,21 @@ unnecessary_dunder_call.py:131:8: PLC2801 [*] Unnecessary dunder call to `__str_
 130 130 | # https://github.com/astral-sh/ruff/issues/14597
 131     |-assert "abc".__str__() == "abc"
     131 |+assert str("abc") == "abc"
+132 132 | 
+133 133 | # https://github.com/astral-sh/ruff/issues/18813
+134 134 | three = 1 if 1 else(3.0).__str__()
+
+unnecessary_dunder_call.py:134:20: PLC2801 [*] Unnecessary dunder call to `__str__`. Use `str()` builtin.
+    |
+133 | # https://github.com/astral-sh/ruff/issues/18813
+134 | three = 1 if 1 else(3.0).__str__()
+    |                    ^^^^^^^^^^^^^^^ PLC2801
+    |
+    = help: Use `str()` builtin
+
+ℹ Unsafe fix
+131 131 | assert "abc".__str__() == "abc"
+132 132 | 
+133 133 | # https://github.com/astral-sh/ruff/issues/18813
+134     |-three = 1 if 1 else(3.0).__str__()
+    134 |+three = 1 if 1 else str(3.0)