[refurb] Further special cases added to `verbose-decimal-constructo…

…r (FURB157)` (#14216)

This PR accounts for further subtleties in `Decimal` parsing:

- Strings which are empty modulo underscores and surrounding whitespace
are skipped
- `Decimal("-0")` is skipped
- `Decimal("{integer literal that is longer than 640 digits}")` are
skipped (see linked issue for explanation)

NB: The snapshot did not need to be updated since the new test cases are
"Ok" instances and added below the diff.

Closes #14204

crates/ruff_linter/resources/test/fixtures/refurb/FURB157.py

@@ -34,4 +34,11 @@
 # Ok: even though this is equal to `Decimal(123)`,
 # we assume that a developer would
 # only write it this way if they meant to.
-Decimal("١٢٣") 
+Decimal("١٢٣") 
+
+# Further subtleties
+# https://github.com/astral-sh/ruff/issues/14204
+Decimal("-0") # Ok
+Decimal("_") # Ok
+Decimal(" ") # Ok
+Decimal("10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000") # Ok

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

@@ -94,6 +94,12 @@ pub(crate) fn verbose_decimal_constructor(checker: &mut Checker, call: &ast::Exp
                 ("", trimmed)
             };
 
+            // Early return if we now have an empty string
+            // or a very long string:
+            if (rest.len() > PYTHONINTMAXSTRDIGITS) || (rest.len() == 0) {
+                return;
+            }
+
             // Skip leading zeros.
             let rest = rest.trim_start_matches('0');
 
@@ -103,7 +109,15 @@ pub(crate) fn verbose_decimal_constructor(checker: &mut Checker, call: &ast::Exp
             };
 
             // If all the characters are zeros, then the value is zero.
-            let rest = if rest.is_empty() { "0" } else { rest };
+            let rest = match (unary, rest.is_empty()) {
+                // `Decimal("-0")` is not the same as `Decimal("0")`
+                // so we return early.
+                ("-", true) => {
+                    return;
+                }
+                (_, true) => "0",
+                _ => rest,
+            };
 
             let replacement = format!("{unary}{rest}");
             let mut diagnostic = Diagnostic::new(
@@ -168,25 +182,10 @@ pub(crate) fn verbose_decimal_constructor(checker: &mut Checker, call: &ast::Exp
     checker.diagnostics.push(diagnostic);
 }
 
-// // Slightly modified from [CPython regex] to ignore  https://github.com/python/cpython/blob/ac556a2ad1213b8bb81372fe6fb762f5fcb076de/Lib/_pydecimal.py#L6060-L6077
-// static DECIMAL_PARSER_REGEX: LazyLock<Regex> = LazyLock::new(|| {
-//     Regex::new(
-//         r"(?x)                   # Verbose mode for comments
-// ^                                             # Start of string
-// (?P<sign>[-+])?                               # Optional sign
-// (?:
-//     (?P<int>\d*)                              # Integer part (can be empty)
-//     (\.(?P<frac>\d+))?                        # Optional fractional part
-//     (E(?P<exp>[-+]?\d+))?                     # Optional exponent
-// |
-//     Inf(inity)?                               # Infinity
-// |
-//     (?P<signal>s)?                            # Optional signal
-//     NaN                                       # NaN
-//     (?P<diag>\d*)                             # Optional diagnostic info
-// )
-// $                                             # End of string
-// ",
-//     )
-//     .unwrap()
-// });
+// ```console
+// $ python
+// >>> import sys
+// >>> sys.int_info.str_digits_check_threshold
+// 640
+// ```
+const PYTHONINTMAXSTRDIGITS: usize = 640;