youknowone · Jun 10, 2026 · Jun 4, 2026 · Jun 4, 2026
diff --git a/crates/capi/src/unicodeobject.rs b/crates/capi/src/unicodeobject.rs
@@ -1,6 +1,5 @@
-use crate::PyObject;
 use crate::object::define_py_check;
-use crate::pystate::with_vm;
+use crate::{PyObject, pystate::with_vm};
 use core::ffi::{CStr, c_char, c_int};
 use core::ptr::NonNull;
 use core::slice;
@@ -92,6 +91,107 @@ pub unsafe extern "C" fn PyUnicode_AsEncodedString(
     })
 }
 
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn PyUnicode_AsUTF8String(unicode: *mut PyObject) -> *mut PyObject {
+    with_vm(|vm| {
+        let unicode = unsafe { &*unicode }
+            .try_downcast_ref::<PyStr>(vm)?
+            .to_owned();
+        vm.state
+            .codec_registry
+            .encode_text(unicode, "utf-8", None, vm)
+    })
+}
+
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn PyUnicode_DecodeFSDefaultAndSize(
+    s: *const c_char,
+    size: isize,
+) -> *mut PyObject {
+    with_vm(|vm| {
+        let size: usize = size
+            .try_into()
+            .map_err(|_| vm.new_system_error("size must be non-negative"))?;
+
+        let bytes = if s.is_null() {
+            if size != 0 {
+                return Err(vm.new_system_error(
+                    "PyUnicode_DecodeFSDefaultAndSize called with null data and non-zero size",
+                ));
+            }
+            &[][..]
+        } else {
+            unsafe { slice::from_raw_parts(s.cast::<u8>(), size) }
+        };
+
+        vm.state.codec_registry.decode_text(
+            vm.ctx.new_bytes(bytes.to_vec()).into(),
+            vm.fs_encoding().as_str(),
+            Some(vm.fs_encode_errors().to_owned()),
+            vm,
+        )
+    })
+}
+
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn PyUnicode_EncodeFSDefault(unicode: *mut PyObject) -> *mut PyObject {
+    with_vm(|vm| {
+        let unicode = unsafe { &*unicode }
+            .try_downcast_ref::<PyStr>(vm)?
+            .to_owned();
+        vm.state.codec_registry.encode_text(
+            unicode,
+            vm.fs_encoding().as_str(),
+            Some(vm.fs_encode_errors().to_owned()),
+            vm,
+        )
+    })
+}
+
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn PyUnicode_FromEncodedObject(
+    obj: *mut PyObject,
+    encoding: *const c_char,
+    errors: *const c_char,
+) -> *mut PyObject {
+    with_vm(|vm| {
+        let obj = unsafe { &*obj };
+
+        if obj.downcast_ref::<PyStr>().is_some() {
+            return Err(vm.new_type_error("decoding str is not supported".to_owned()));
+        }
+
+        let encoding = if encoding.is_null() {
+            "utf-8"
+        } else {
+            unsafe { CStr::from_ptr(encoding) }
+                .to_str()
+                .map_err(|_| vm.new_system_error("encoding must be valid UTF-8"))?
+        };
+        let errors = if errors.is_null() {
+            None
+        } else {
+            let errors = unsafe { CStr::from_ptr(errors) }
+                .to_str()
+                .map_err(|_| vm.new_system_error("errors must be valid UTF-8"))?;
+            Some(vm.ctx.new_utf8_str(errors))
+        };
+
+        let decoded = obj.try_bytes_like(vm, |b| {
+            vm.state.codec_registry.decode_text(
+                vm.ctx.new_bytes(b.to_vec()).into(),
+                encoding,
+                errors,
+                vm,
+            )
+        });
+
+        decoded.map_err(|_| {
+            vm.new_type_error("decoding to str: need a bytes-like object, not str".to_owned())
+        })?
+    })
+}
+
 #[unsafe(no_mangle)]
 pub unsafe extern "C" fn PyUnicode_InternInPlace(string: *mut *mut PyObject) {
     with_vm(|vm| {
@@ -131,12 +231,17 @@ pub unsafe extern "C" fn PyUnicode_EqualToUTF8AndSize(
 
 #[cfg(false)]
 mod tests {
+    use std::ffi::{OsStr, OsString};
+
     use pyo3::intern;
     use pyo3::prelude::*;
-    use pyo3::types::PyString;
+    use pyo3::types::{PyBytes, PyString, PyStringMethods};
+
+    #[cfg(unix)]
+    use std::os::unix::ffi::OsStrExt;
 
     #[test]
-    fn test_unicode() {
+    fn unicode() {
         Python::attach(|py| {
             let string = PyString::new(py, "Hello, World!");
             assert!(string.is_instance_of::<PyString>());
@@ -146,9 +251,48 @@ mod tests {
     }
 
     #[test]
-    fn test_intern_str() {
+    fn intern_str() {
         Python::attach(|py| {
             let _string = intern!(py, "Hello, World!");
         })
     }
+
+    #[test]
+    fn encode_utf8_via_wrapper() {
+        Python::attach(|py| {
+            let s = PyString::new(py, "h\u{00E9}llo");
+            let encoded = s.encode_utf8().unwrap();
+            assert_eq!(encoded.as_bytes(), "h\u{00E9}llo".as_bytes());
+        })
+    }
+
+    #[test]
+    fn from_encoded_object_bytes() {
+        Python::attach(|py| {
+            let src = PyBytes::new(py, b"h\xC3\xA9llo");
+            let s = PyString::from_encoded_object(src.as_any(), None, None).unwrap();
+            assert_eq!(s.to_str().unwrap(), "h\u{00E9}llo");
+        })
+    }
+
+    #[cfg(unix)]
+    #[test]
+    fn fs_default_roundtrip_non_utf8_unix() {
+        Python::attach(|py| {
+            let original = OsStr::from_bytes(&[b'f', b'o', 0x80]);
+            let py_str = original.into_pyobject(py).unwrap();
+            let roundtrip: OsString = py_str.extract().unwrap();
+            assert_eq!(roundtrip.as_os_str().as_bytes(), original.as_bytes());
+        })
+    }
+
+    #[test]
+    fn fs_default_roundtrip_utf8() {
+        Python::attach(|py| {
+            let original = OsStr::new("hello.txt");
+            let py_str = original.into_pyobject(py).unwrap();
+            let roundtrip: OsString = py_str.extract().unwrap();
+            assert_eq!(roundtrip, original);
+        })
+    }
 }