Skip to content

[ruff] Ignore str() when not used for simple conversion (RUF065) #21330

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
ntBre merged 6 commits into from
Nov 10, 2025
Merged

[ruff] Ignore str() when not used for simple conversion (RUF065) #21330

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
6 commits
Select commit Hold shift + click to select a range
30efe9a
fix-21315
danparizher Nov 7, 2025
c830f26
flag `logging.warning("%s", str(object="!"))`
danparizher Nov 8, 2025
fe60f9f
Simplify
danparizher Nov 10, 2025
e624a8b
Separate test files
danparizher Nov 10, 2025
e4301fc
update test names
ntBre Nov 10, 2025
3551c6f
revert line removal
ntBre Nov 10, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
13 changes: 13 additions & 0 deletions crates/ruff_linter/resources/test/fixtures/ruff/RUF065.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -69,3 +69,16 @@ def str(s): return f"str = {s}"
info("Hex: %s", hex(42))
log(logging.INFO, "Hex: %s", hex(255))

# Test cases for str() that should NOT be flagged (issue #21315)
# str() with no arguments - should not be flagged
logging.warning("%s", str())

# str() with multiple arguments - should not be flagged
logging.warning("%s", str(b"\xe2\x9a\xa0", "utf-8"))

# str() with starred arguments - should not be flagged
logging.warning("%s", str(*(b"\xf0\x9f\x9a\xa7", "utf-8")))

# str() with keyword unpacking - should not be flagged
logging.warning("%s", str(**{"object": b"\xf0\x9f\x9a\xa8", "encoding": "utf-8"}))

13 changes: 11 additions & 2 deletions crates/ruff_linter/src/rules/ruff/rules/logging_eager_conversion.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -138,16 +138,25 @@ pub(crate) fn logging_eager_conversion(checker: &Checker, call: &ast::ExprCall)
.zip(call.arguments.args.iter().skip(msg_pos + 1))
{
// Check if the argument is a call to eagerly format a value
if let Expr::Call(ast::ExprCall { func, .. }) = arg {
if let Expr::Call(ast::ExprCall {
func,
arguments: str_call_args,
..
}) = arg
{
let CFormatType::String(format_conversion) = spec.format_type else {
continue;
};

// Check for various eager conversion patterns
match format_conversion {
// %s with str() - remove str() call
// Only flag if str() has exactly one non-starred positional argument and no keyword arguments
FormatConversion::Str
if checker.semantic().match_builtin_expr(func.as_ref(), "str") =>
if checker.semantic().match_builtin_expr(func.as_ref(), "str")
&& str_call_args.args.len() == 1
&& !str_call_args.args[0].is_starred_expr()
&& str_call_args.keywords.is_empty() =>
Copy link

@dscorbett dscorbett Nov 8, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

logging.warning("%s", str(object="!")), with one keyword argument, should still be flagged.

{
checker.report_diagnostic(
LoggingEagerConversion {
Expand Down
2 changes: 2 additions & 0 deletions ...ff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__RUF065_RUF065.py.snap
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -216,4 +216,6 @@ RUF065 Unnecessary `hex()` conversion when formatting with `%s`. Use `%#x` inste
69 | info("Hex: %s", hex(42))
70 | log(logging.INFO, "Hex: %s", hex(255))
| ^^^^^^^^
71 |
72 | # Test cases for str() that should NOT be flagged (issue #21315)
|