From 3d03e75a9d42c4d519062677405bc2fce307a22a Mon Sep 17 00:00:00 2001
From: Charlie Marsh <charlie.r.marsh@gmail.com>
Date: Sun, 15 Oct 2023 21:41:50 -0400
Subject: [PATCH] Force parentheses for power operations in unary expressions
 (#7955)

## Summary

E.g., given `-10**100`, reformat as `-(10**100)`.

Black special cases this (https://github.com/psf/black/pull/909) and
it's currently a deviation.

Closes https://github.com/astral-sh/ruff/issues/7951.
---
 .../src/expression/expr_unary_op.rs                   | 11 +++++++++--
 ...ack_compatibility@simple_cases__expression.py.snap | 11 +----------
 2 files changed, 10 insertions(+), 12 deletions(-)

diff --git a/crates/ruff_python_formatter/src/expression/expr_unary_op.rs b/crates/ruff_python_formatter/src/expression/expr_unary_op.rs
index 62646e2da8..cd5d30e97b 100644
--- a/crates/ruff_python_formatter/src/expression/expr_unary_op.rs
+++ b/crates/ruff_python_formatter/src/expression/expr_unary_op.rs
@@ -4,7 +4,7 @@ use ruff_python_ast::UnaryOp;
 
 use crate::comments::{trailing_comments, SourceComment};
 use crate::expression::parentheses::{
-    is_expression_parenthesized, NeedsParentheses, OptionalParentheses,
+    is_expression_parenthesized, NeedsParentheses, OptionalParentheses, Parentheses,
 };
 use crate::prelude::*;
 
@@ -57,7 +57,14 @@ impl FormatNodeRule<ExprUnaryOp> for FormatExprUnaryOp {
             space().fmt(f)?;
         }
 
-        operand.format().fmt(f)
+        if operand
+            .as_bin_op_expr()
+            .is_some_and(|bin_op| bin_op.op.is_pow())
+        {
+            operand.format().with_options(Parentheses::Always).fmt(f)
+        } else {
+            operand.format().fmt(f)
+        }
     }
 
     fn fmt_dangling_comments(
diff --git a/crates/ruff_python_formatter/tests/snapshots/black_compatibility@simple_cases__expression.py.snap b/crates/ruff_python_formatter/tests/snapshots/black_compatibility@simple_cases__expression.py.snap
index 43e5c13e54..02a6a4a76c 100644
--- a/crates/ruff_python_formatter/tests/snapshots/black_compatibility@simple_cases__expression.py.snap
+++ b/crates/ruff_python_formatter/tests/snapshots/black_compatibility@simple_cases__expression.py.snap
@@ -266,15 +266,6 @@ last_call()
 ```diff
 --- Black
 +++ Ruff
-@@ -31,7 +31,7 @@
- -1
- ~int and not v1 ^ 123 + v2 | True
- (~int) and (not ((v1 ^ (123 + v2)) | True))
--+(really ** -(confusing ** ~(operator**-precedence)))
-++really ** -confusing ** ~operator**-precedence
- flags & ~select.EPOLLIN and waiters.write_task is not None
- lambda arg: None
- lambda a=True: a
 @@ -115,7 +115,7 @@
      arg,
      another,
@@ -322,7 +313,7 @@ not great
 -1
 ~int and not v1 ^ 123 + v2 | True
 (~int) and (not ((v1 ^ (123 + v2)) | True))
-+really ** -confusing ** ~operator**-precedence
++(really ** -(confusing ** ~(operator**-precedence)))
 flags & ~select.EPOLLIN and waiters.write_task is not None
 lambda arg: None
 lambda a=True: a