RustPython · youknowone · Jan 1, 2026 · Dec 31, 2025 · Dec 31, 2025 · Jan 1, 2026
diff --git a/.cspell.dict/python-more.txt b/.cspell.dict/python-more.txt
@@ -178,6 +178,7 @@ PYTHONHASHSEED
 PYTHONHOME
 PYTHONINSPECT
 PYTHONINTMAXSTRDIGITS
+PYTHONIOENCODING
 PYTHONNODEBUGRANGES
 PYTHONNOUSERSITE
 PYTHONOPTIMIZE

diff --git a/Lib/test/test_tarfile.py b/Lib/test/test_tarfile.py
@@ -2494,8 +2494,6 @@ def test_test_command_invalid_file(self):
                 finally:
                     os_helper.unlink(tmpname)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_list_command(self):
         for tar_name in testtarnames:
             with support.captured_stdout() as t:
@@ -2507,8 +2505,6 @@ def test_list_command(self):
                                       PYTHONIOENCODING='ascii')
                 self.assertEqual(out, expected)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_list_command_verbose(self):
         for tar_name in testtarnames:
             with support.captured_stdout() as t:

diff --git a/crates/vm/Lib/core_modules/encodings_ascii.py b/crates/vm/Lib/core_modules/encodings_ascii.py
@@ -0,0 +1 @@
+../../../../Lib/encodings/ascii.py
diff --git a/crates/vm/src/vm/mod.rs b/crates/vm/src/vm/mod.rs
@@ -261,17 +261,28 @@ impl VirtualMachine {
         Ok(())
     }
 
-    fn import_utf8_encodings(&mut self) -> PyResult<()> {
+    fn import_ascii_utf8_encodings(&mut self) -> PyResult<()> {
         import::import_frozen(self, "codecs")?;
-        // FIXME: See corresponding part of `core_frozen_inits`
-        // let encoding_module_name = if cfg!(feature = "freeze-stdlib") {
-        //     "encodings.utf_8"
-        // } else {
-        //     "encodings_utf_8"
-        // };
-        let encoding_module_name = "encodings_utf_8";
-        let encoding_module = import::import_frozen(self, encoding_module_name)?;
-        let getregentry = encoding_module.get_attr("getregentry", self)?;
+
+        // Use dotted names when freeze-stdlib is enabled (modules come from Lib/encodings/),
+        // otherwise use underscored names (modules come from core_modules/).
+        let (ascii_module_name, utf8_module_name) = if cfg!(feature = "freeze-stdlib") {
+            ("encodings.ascii", "encodings.utf_8")
+        } else {
+            ("encodings_ascii", "encodings_utf_8")
+        };
+
+        // Register ascii encoding
+        let ascii_module = import::import_frozen(self, ascii_module_name)?;
+        let getregentry = ascii_module.get_attr("getregentry", self)?;
+        let codec_info = getregentry.call((), self)?;
+        self.state
+            .codec_registry
+            .register_manual("ascii", codec_info.try_into_value(self)?)?;
+
+        // Register utf-8 encoding
+        let utf8_module = import::import_frozen(self, utf8_module_name)?;
+        let getregentry = utf8_module.get_attr("getregentry", self)?;
         let codec_info = getregentry.call((), self)?;
         self.state
             .codec_registry
@@ -298,7 +309,7 @@ impl VirtualMachine {
             #[cfg(not(feature = "threading"))]
             import::import_frozen(self, "_thread")?;
             let importlib = import::init_importlib_base(self)?;
-            self.import_utf8_encodings()?;
+            self.import_ascii_utf8_encodings()?;
 
             #[cfg(any(not(target_arch = "wasm32"), target_os = "wasi"))]
             {
@@ -327,17 +338,25 @@ impl VirtualMachine {
                     let line_buffering = buffered_stdio && (isatty || fd == 2);
 
                     let newline = if cfg!(windows) { None } else { Some("\n") };
-                    // stderr uses backslashreplace error handler
-                    let errors: Option<&str> = if fd == 2 {
+                    let encoding = self.state.config.settings.stdio_encoding.as_deref();
+                    // stderr always uses backslashreplace (ignores stdio_errors)
+                    let errors = if fd == 2 {
                         Some("backslashreplace")
                     } else {
-                        None
+                        self.state.config.settings.stdio_errors.as_deref()
                     };
 
                     let stdio = self.call_method(
                         &io,
                         "TextIOWrapper",
-                        (buf, (), errors, newline, line_buffering, write_through),
+                        (
+                            buf,
+                            encoding,
+                            errors,
+                            newline,
+                            line_buffering,
+                            write_through,
+                        ),
                     )?;
                     let mode = if write { "w" } else { "r" };
                     stdio.set_attr("mode", self.ctx.new_str(mode), self)?;
@@ -1007,6 +1026,8 @@ pub fn resolve_frozen_alias(name: &str) -> &str {
     match name {
         "_frozen_importlib" => "importlib._bootstrap",
         "_frozen_importlib_external" => "importlib._bootstrap_external",
+        "encodings_ascii" => "encodings.ascii",
+        "encodings_utf_8" => "encodings.utf_8",
         _ => name,
     }
 }

diff --git a/crates/vm/src/vm/setting.rs b/crates/vm/src/vm/setting.rs
@@ -112,9 +112,11 @@ pub struct Settings {
     /// -u, PYTHONUNBUFFERED=x
     pub buffered_stdio: bool,
 
-    // wchar_t *stdio_encoding;
+    /// PYTHONIOENCODING - stdio encoding
+    pub stdio_encoding: Option<String>,
+    /// PYTHONIOENCODING - stdio error handler
+    pub stdio_errors: Option<String>,
     pub utf8_mode: u8,
-    // wchar_t *stdio_errors;
     /// --check-hash-based-pycs
     pub check_hash_pycs_mode: CheckHashPycsMode,
 
@@ -197,6 +199,8 @@ impl Default for Settings {
             buffered_stdio: true,
             check_hash_pycs_mode: CheckHashPycsMode::Default,
             allow_external_library: cfg!(feature = "importlib"),
+            stdio_encoding: None,
+            stdio_errors: None,
             utf8_mode: 1,
             int_max_str_digits: 4300,
             #[cfg(feature = "flame-it")]

diff --git a/src/settings.rs b/src/settings.rs
@@ -298,6 +298,23 @@ pub fn parse_opts() -> Result<(Settings, RunMode), lexopt::Error> {
         settings.code_debug_ranges = false;
     }
 
+    // Parse PYTHONIOENCODING=encoding[:errors]
+    if let Some(val) = get_env("PYTHONIOENCODING")
+        && let Some(val_str) = val.to_str()
+        && !val_str.is_empty()
+    {
+        if let Some((enc, err)) = val_str.split_once(':') {
+            if !enc.is_empty() {
+                settings.stdio_encoding = Some(enc.to_owned());
+            }
+            if !err.is_empty() {
+                settings.stdio_errors = Some(err.to_owned());
+            }
+        } else {
+            settings.stdio_encoding = Some(val_str.to_owned());
+        }
+    }
+
     if settings.dev_mode {
         settings.warnoptions.push("default".to_owned());
         settings.faulthandler = true;