Respect parentheses for precedence in await (#7468)

## Summary

We were using `Parenthesize::IfBreaks` universally for `await`, but
dropping parentheses can change the AST due to precedence. It turns out
that Black's rules aren't _exactly_ the same as operator precedence
(e.g., they leave parentheses around `await ([1, 2, 3])`, although they
aren't strictly required).

Closes https://github.com/astral-sh/ruff/issues/7467.

## Test Plan

`cargo test`

No change in similarity.

Before:

| project | similarity index | total files | changed files |

|--------------|------------------:|------------------:|------------------:|
| cpython | 0.76083 | 1789 | 1632 |
| django | 0.99982 | 2760 | 37 |
| transformers | 0.99957 | 2587 | 398 |
| twine | 1.00000 | 33 | 0 |
| typeshed | 0.99983 | 3496 | 18 |
| warehouse | 0.99929 | 648 | 16 |
| zulip | 0.99962 | 1437 | 22 |

After:

| project | similarity index | total files | changed files |

|--------------|------------------:|------------------:|------------------:|
| cpython | 0.76083 | 1789 | 1632 |
| django | 0.99982 | 2760 | 37 |
| transformers | 0.99957 | 2587 | 398 |
| twine | 1.00000 | 33 | 0 |
| typeshed | 0.99983 | 3496 | 18 |
| warehouse | 0.99929 | 648 | 16 |
| zulip | 0.99962 | 1437 | 22 |

crates/ruff_python_formatter/README.md

@@ -305,3 +305,21 @@ import os
 
 import sys
 ```
+
+### Parentheses around awaited collections are not preserved
+
+Black preserves parentheses around awaited collections:
+
+```python
+await ([1, 2, 3])
+```
+
+Ruff will instead remove them:
+
+```python
+await [1, 2, 3]
+```
+
+This is more consistent to the formatting of other awaited expressions: Ruff and Black both
+remove parentheses around, e.g., `await (1)`, only retaining them when syntactically required,
+as in, e.g., `await (x := 1)`.

crates/ruff_python_formatter/resources/test/fixtures/ruff/expression/await.py

@@ -10,3 +10,41 @@ result = await (self.request(
 result = await (1 + f(1, 2, 3,))
 
 result = (await (1 + f(1, 2, 3,)))
+
+# Optional parentheses.
+await foo
+await (foo)
+await foo()
+await (foo())
+await []()
+await ([]())
+await (foo + bar)()
+await ((foo + bar)())
+await foo.bar
+await (foo.bar)
+await foo['bar']
+await (foo['bar'])
+await 1
+await (1)
+await ""
+await ("")
+await f""
+await (f"")
+await [foo]
+await ([foo])
+await {foo}
+await ({foo})
+await (lambda foo: foo)
+await (foo or bar)
+await (foo * bar)
+await (yield foo)
+await (not foo)
+await 1, 2, 3
+await (1, 2, 3)
+await ( # comment
+    [foo]
+)
+await (
+    # comment
+    [foo]
+)

crates/ruff_python_formatter/src/expression/expr_bin_op.rs

@@ -33,7 +33,7 @@ impl NeedsParentheses for ExprBinOp {
         parent: AnyNodeRef,
         context: &PyFormatContext,
     ) -> OptionalParentheses {
-        if parent.is_expr_await() && !self.op.is_pow() {
+        if parent.is_expr_await() {
             OptionalParentheses::Always
         } else if let Expr::Constant(constant) = self.left.as_ref() {
             // Multiline strings are guaranteed to never fit, avoid adding unnecessary parentheses

crates/ruff_python_formatter/src/expression/expr_bool_op.rs

@@ -19,10 +19,14 @@ impl FormatNodeRule<ExprBoolOp> for FormatExprBoolOp {
 impl NeedsParentheses for ExprBoolOp {
     fn needs_parentheses(
         &self,
-        _parent: AnyNodeRef,
+        parent: AnyNodeRef,
         _context: &PyFormatContext,
     ) -> OptionalParentheses {
-        OptionalParentheses::Multiline
+        if parent.is_expr_await() {
+            OptionalParentheses::Always
+        } else {
+            OptionalParentheses::Multiline
+        }
     }
 }
 

crates/ruff_python_formatter/src/expression/expr_compare.rs

@@ -31,10 +31,12 @@ impl FormatNodeRule<ExprCompare> for FormatExprCompare {
 impl NeedsParentheses for ExprCompare {
     fn needs_parentheses(
         &self,
-        _parent: AnyNodeRef,
+        parent: AnyNodeRef,
         context: &PyFormatContext,
     ) -> OptionalParentheses {
-        if let Expr::Constant(constant) = self.left.as_ref() {
+        if parent.is_expr_await() {
+            OptionalParentheses::Always
+        } else if let Expr::Constant(constant) = self.left.as_ref() {
             // Multiline strings are guaranteed to never fit, avoid adding unnecessary parentheses
             if !constant.value.is_implicit_concatenated()
                 && is_multiline_string(constant, context.source())

crates/ruff_python_formatter/src/expression/expr_generator_exp.rs

@@ -91,10 +91,14 @@ impl FormatNodeRule<ExprGeneratorExp> for FormatExprGeneratorExp {
 impl NeedsParentheses for ExprGeneratorExp {
     fn needs_parentheses(
         &self,
-        _parent: AnyNodeRef,
+        parent: AnyNodeRef,
         _context: &PyFormatContext,
     ) -> OptionalParentheses {
-        OptionalParentheses::Never
+        if parent.is_expr_await() {
+            OptionalParentheses::Always
+        } else {
+            OptionalParentheses::Never
+        }
     }
 }
 

crates/ruff_python_formatter/src/expression/expr_if_exp.rs

@@ -85,10 +85,14 @@ impl FormatNodeRule<ExprIfExp> for FormatExprIfExp {
 impl NeedsParentheses for ExprIfExp {
     fn needs_parentheses(
         &self,
-        _parent: AnyNodeRef,
+        parent: AnyNodeRef,
         _context: &PyFormatContext,
     ) -> OptionalParentheses {
-        OptionalParentheses::Multiline
+        if parent.is_expr_await() {
+            OptionalParentheses::Always
+        } else {
+            OptionalParentheses::Multiline
+        }
     }
 }
 

crates/ruff_python_formatter/src/expression/expr_lambda.rs

@@ -64,9 +64,13 @@ impl FormatNodeRule<ExprLambda> for FormatExprLambda {
 impl NeedsParentheses for ExprLambda {
     fn needs_parentheses(
         &self,
-        _parent: AnyNodeRef,
+        parent: AnyNodeRef,
         _context: &PyFormatContext,
     ) -> OptionalParentheses {
-        OptionalParentheses::Multiline
+        if parent.is_expr_await() {
+            OptionalParentheses::Always
+        } else {
+            OptionalParentheses::Multiline
+        }
     }
 }

crates/ruff_python_formatter/src/expression/expr_unary_op.rs

@@ -72,11 +72,12 @@ impl FormatNodeRule<ExprUnaryOp> for FormatExprUnaryOp {
 impl NeedsParentheses for ExprUnaryOp {
     fn needs_parentheses(
         &self,
-        _parent: AnyNodeRef,
+        parent: AnyNodeRef,
         context: &PyFormatContext,
     ) -> OptionalParentheses {
-        // We preserve the parentheses of the operand. It should not be necessary to break this expression.
+        if parent.is_expr_await() {
-        if is_expression_parenthesized(
+            OptionalParentheses::Always
+        } else if is_expression_parenthesized(
             self.operand.as_ref().into(),
             context.comments().ranges(),
             context.source(),

crates/ruff_python_formatter/tests/snapshots/format@expression__await.py.snap

@@ -16,6 +16,44 @@ result = await (self.request(
 result = await (1 + f(1, 2, 3,))
 
 result = (await (1 + f(1, 2, 3,)))
+
+# Optional parentheses.
+await foo
+await (foo)
+await foo()
+await (foo())
+await []()
+await ([]())
+await (foo + bar)()
+await ((foo + bar)())
+await foo.bar
+await (foo.bar)
+await foo['bar']
+await (foo['bar'])
+await 1
+await (1)
+await ""
+await ("")
+await f""
+await (f"")
+await [foo]
+await ([foo])
+await {foo}
+await ({foo})
+await (lambda foo: foo)
+await (foo or bar)
+await (foo * bar)
+await (yield foo)
+await (not foo)
+await 1, 2, 3
+await (1, 2, 3)
+await ( # comment
+    [foo]
+)
+await (
+    # comment
+    [foo]
+)
 ```
 
 ## Output
@@ -46,6 +84,44 @@ result = await (
         3,
     )
 )
+
+# Optional parentheses.
+await foo
+await foo
+await foo()
+await foo()
+await []()
+await []()
+await (foo + bar)()
+await (foo + bar)()
+await foo.bar
+await foo.bar
+await foo["bar"]
+await foo["bar"]
+await 1
+await 1
+await ""
+await ""
+await f""
+await f""
+await [foo]
+await [foo]
+await {foo}
+await {foo}
+await (lambda foo: foo)
+await (foo or bar)
+await (foo * bar)
+await (yield foo)
+await (not foo)
+await 1, 2, 3
+await (1, 2, 3)
+await (  # comment
+    [foo]
+)
+await (
+    # comment
+    [foo]
+)
 ```