From 752c0f68fd76b76aa85552be33a880fac65745e7 Mon Sep 17 00:00:00 2001
From: "Jeong, YunWon" <jeong@youknowone.org>
Date: Fri, 12 Dec 2025 20:12:30 +0900
Subject: [PATCH] fix windows locale

---
 Lib/test/test_locale.py     |  1 -
 crates/stdlib/src/locale.rs | 43 +++++++++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/Lib/test/test_locale.py b/Lib/test/test_locale.py
index 9e1f46f64..71d03f3a3 100644
--- a/Lib/test/test_locale.py
+++ b/Lib/test/test_locale.py
@@ -511,7 +511,6 @@ class TestRealLocales(unittest.TestCase):
             self.skipTest(f"setlocale(LC_CTYPE, {loc!r}) failed: {exc!r}")
         self.assertEqual(loc, locale.getlocale(locale.LC_CTYPE))
 
-    @unittest.expectedFailureIfWindows('TODO: RUSTPYTHON; Error not raised')
     @unittest.skipUnless(os.name == 'nt', 'requires Windows')
     def test_setlocale_long_encoding(self):
         with self.assertRaises(locale.Error):
diff --git a/crates/stdlib/src/locale.rs b/crates/stdlib/src/locale.rs
index 630d2a419..6cca8b912 100644
--- a/crates/stdlib/src/locale.rs
+++ b/crates/stdlib/src/locale.rs
@@ -198,6 +198,34 @@ mod _locale {
         locale: OptionalArg<Option<PyStrRef>>,
     }
 
+    /// Maximum code page encoding name length on Windows
+    #[cfg(windows)]
+    const MAX_CP_LEN: usize = 15;
+
+    /// Check if the encoding part of a locale string is too long (Windows only)
+    #[cfg(windows)]
+    fn check_locale_name(locale: &str) -> bool {
+        if let Some(dot_pos) = locale.find('.') {
+            let encoding_part = &locale[dot_pos + 1..];
+            // Find the end of encoding (could be followed by '@' modifier)
+            let encoding_len = encoding_part.find('@').unwrap_or(encoding_part.len());
+            encoding_len <= MAX_CP_LEN
+        } else {
+            true
+        }
+    }
+
+    /// Check locale names for LC_ALL (handles semicolon-separated locales)
+    #[cfg(windows)]
+    fn check_locale_name_all(locale: &str) -> bool {
+        for part in locale.split(';') {
+            if !check_locale_name(part) {
+                return false;
+            }
+        }
+        true
+    }
+
     #[pyfunction]
     fn setlocale(args: LocaleArgs, vm: &VirtualMachine) -> PyResult {
         let error = error(vm);
@@ -208,6 +236,21 @@ mod _locale {
             let result = match args.locale.flatten() {
                 None => libc::setlocale(args.category, ptr::null()),
                 Some(locale) => {
+                    // On Windows, validate encoding name length
+                    #[cfg(windows)]
+                    {
+                        let valid = if args.category == LC_ALL {
+                            check_locale_name_all(locale.as_str())
+                        } else {
+                            check_locale_name(locale.as_str())
+                        };
+                        if !valid {
+                            return Err(vm.new_exception_msg(
+                                error,
+                                String::from("unsupported locale setting"),
+                            ));
+                        }
+                    }
                     let c_locale: CString =
                         CString::new(locale.as_str()).map_err(|e| e.to_pyexception(vm))?;
                     libc::setlocale(args.category, c_locale.as_ptr())