[ruff] Avoid f-string false positives in gettext calls (RUF027) (…

…astral-sh#10118)

## Summary

It is a convention to use the `_()` alias for `gettext()`. We want to
avoid
statement expressions and assignments related to aliases of the gettext
API.
See https://docs.python.org/3/library/gettext.html for details. When one
uses `_() to mark a string for translation, the tools look for these
markers
and replace the original string with its translated counterpart. If the
string contains variable placeholders or formatting, it can complicate
the
translation process, lead to errors or incorrect translations.

## Test Plan

* Test file `RUF027_1.py` was extended such that the test reproduces the
false-positive

Closes astral-sh#10023.

---------

Co-authored-by: Charlie Marsh <charlie.r.marsh@gmail.com>

crates/ruff_linter/resources/test/fixtures/ruff/RUF027_1.py

@@ -25,6 +25,10 @@ def negative_cases():
     json3 = "{ 'positive': 'false' }"
     alternative_formatter("{a}", a=5)
     formatted = "{a}".fmt(a=7)
+    partial = "partial sentence"
+    a = _("formatting of {partial} in a translation string is bad practice")
+    _("formatting of {partial} in a translation string is bad practice")
+    print(_("formatting of {partial} in a translation string is bad practice"))
     print(do_nothing("{a}".format(a=3)))
     print(do_nothing(alternative_formatter("{a}", a=5)))
     print(format(do_nothing("{a}"), a=5))

crates/ruff_linter/src/rules/ruff/rules/missing_fstring_syntax.rs

@@ -70,13 +70,38 @@ pub(crate) fn missing_fstring_syntax(
         }
     }
 
+    // We also want to avoid expressions that are intended to be translated.
+    if semantic.current_expressions().any(is_gettext) {
+        return;
+    }
+
     if should_be_fstring(literal, locator, semantic) {
         let diagnostic = Diagnostic::new(MissingFStringSyntax, literal.range())
             .with_fix(fix_fstring_syntax(literal.range()));
         diagnostics.push(diagnostic);
     }
 }
 
+/// Returns `true` if an expression appears to be a `gettext` call.
+///
+/// We want to avoid statement expressions and assignments related to aliases
+/// of the gettext API.
+///
+/// See <https://docs.python.org/3/library/gettext.html> for details. When one
+/// uses `_` to mark a string for translation, the tools look for these markers
+/// and replace the original string with its translated counterpart. If the
+/// string contains variable placeholders or formatting, it can complicate the
+/// translation process, lead to errors or incorrect translations.
+fn is_gettext(expr: &ast::Expr) -> bool {
+    let ast::Expr::Call(ast::ExprCall { func, .. }) = expr else {
+        return false;
+    };
+    let ast::Expr::Name(ast::ExprName { id, .. }) = func.as_ref() else {
+        return false;
+    };
+    matches!(id.as_str(), "_" | "gettext" | "ngettext")
+}
+
 /// Returns `true` if `literal` is likely an f-string with a missing `f` prefix.
 /// See [`MissingFStringSyntax`] for the validation criteria.
 fn should_be_fstring(