[refurb] Avoid triggering hardcoded-string-charset for reordered …

…sets (#14233)

## Summary

It's only safe to enforce the `x in "1234567890"` case if `x` is exactly
one character, since the set on the right has been reordered as compared
to `string.digits`. We can't know if `x` is exactly one character unless
it's a literal. And if it's a literal, well, it's kind of silly code in
the first place?

Closes #13802.

crates/ruff_linter/resources/test/fixtures/refurb/FURB156.py

@@ -9,8 +9,6 @@
 _ = r"""!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~"""
 _ = " \t\n\r\v\f"
 
-_ = "" in "1234567890"
-_ = "" in "12345670"
 _ = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ!"#$%&\'()*+,-./:;<=>?@[\\]^_`{|}~ \t\n\r\x0b\x0c'
 _ = (
     '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ!"#$%&'
@@ -19,23 +17,6 @@
 _ = id("0123"
        "4567"
        "89")
-_ = "" in ("123"
-           "456"
-           "789"
-           "0")
-
-_ = "" in ( # comment
-    "123"
-    "456"
-    "789"
-    "0")
-
-
-_ = "" in (
-    "123"
-    "456" # inline comment
-    "789"
-    "0")
 
 _ = (
     "0123456789"
@@ -46,8 +27,8 @@
     # with comment
 ).capitalize()
 
-# Ok
+# OK
 
 _ = "1234567890"
 _ = "1234"
-_ = "" in "1234"
+_ = "12" in "12345670"

crates/ruff_linter/src/checkers/ast/analyze/expression.rs

@@ -1371,9 +1371,6 @@ pub(crate) fn expression(expr: &Expr, checker: &mut Checker) {
             if checker.enabled(Rule::SingleItemMembershipTest) {
                 refurb::rules::single_item_membership_test(checker, expr, left, ops, comparators);
             }
-            if checker.enabled(Rule::HardcodedStringCharset) {
-                refurb::rules::hardcoded_string_charset_comparison(checker, compare);
-            }
         }
         Expr::NumberLiteral(number_literal @ ast::ExprNumberLiteral { .. }) => {
             if checker.source_type.is_stub() && checker.enabled(Rule::NumericLiteralTooLong) {

crates/ruff_linter/src/rules/refurb/rules/hardcoded_string_charset.rs

@@ -2,7 +2,7 @@ use crate::checkers::ast::Checker;
 use crate::importer::ImportRequest;
 use ruff_diagnostics::{AlwaysFixableViolation, Diagnostic, Edit, Fix};
 use ruff_macros::{derive_message_formats, violation};
-use ruff_python_ast::{CmpOp, Expr, ExprCompare, ExprStringLiteral};
+use ruff_python_ast::ExprStringLiteral;
 use ruff_text_size::TextRange;
 
 /// ## What it does
@@ -44,14 +44,22 @@ impl AlwaysFixableViolation for HardcodedStringCharset {
     }
 }
 
+/// FURB156
+pub(crate) fn hardcoded_string_charset_literal(checker: &mut Checker, expr: &ExprStringLiteral) {
+    if let Some(charset) = check_charset_exact(expr.value.to_str().as_bytes()) {
+        push_diagnostic(checker, expr.range, charset);
+    }
+}
+
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
 struct NamedCharset {
     name: &'static str,
     bytes: &'static [u8],
     ascii_char_set: AsciiCharSet,
 }
 
 /// Represents the set of ascii characters in form of a bitset.
-#[derive(Copy, Clone, Eq, PartialEq)]
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
 struct AsciiCharSet(u128);
 
 impl AsciiCharSet {
@@ -108,14 +116,6 @@ const KNOWN_NAMED_CHARSETS: [NamedCharset; 9] = [
     NamedCharset::new("whitespace", b" \t\n\r\x0b\x0c"),
 ];
 
-fn check_charset_as_set(bytes: &[u8]) -> Option<&NamedCharset> {
-    let ascii_char_set = AsciiCharSet::from_bytes(bytes)?;
-
-    KNOWN_NAMED_CHARSETS
-        .iter()
-        .find(|&charset| charset.ascii_char_set == ascii_char_set)
-}
-
 fn check_charset_exact(bytes: &[u8]) -> Option<&NamedCharset> {
     KNOWN_NAMED_CHARSETS
         .iter()
@@ -138,34 +138,3 @@ fn push_diagnostic(checker: &mut Checker, range: TextRange, charset: &NamedChars
     });
     checker.diagnostics.push(diagnostic);
 }
-
-/// FURB156
-pub(crate) fn hardcoded_string_charset_comparison(checker: &mut Checker, compare: &ExprCompare) {
-    let (
-        [CmpOp::In | CmpOp::NotIn],
-        [Expr::StringLiteral(string_literal @ ExprStringLiteral { value, .. })],
-    ) = (compare.ops.as_ref(), compare.comparators.as_ref())
-    else {
-        return;
-    };
-
-    let bytes = value.to_str().as_bytes();
-
-    let Some(charset) = check_charset_as_set(bytes) else {
-        return;
-    };
-
-    // In this case the diagnostic will be emitted via string_literal check.
-    if charset.bytes == bytes {
-        return;
-    }
-
-    push_diagnostic(checker, string_literal.range, charset);
-}
-
-/// FURB156
-pub(crate) fn hardcoded_string_charset_literal(checker: &mut Checker, expr: &ExprStringLiteral) {
-    if let Some(charset) = check_charset_exact(expr.value.to_str().as_bytes()) {
-        push_diagnostic(checker, expr.range, charset);
-    }
-}