From 3f227adc6120b5e3c9d953373d909d3ef254fab2 Mon Sep 17 00:00:00 2001
From: Sylvestre Ledru <sylvestre@debian.org>
Date: Thu, 2 Apr 2026 21:36:07 +0200
Subject: [PATCH] uucore: use wasi OsStrExt/OsStringExt for byte-level access
 on wasm
MIME-Version: 1.0
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WASI provides std::os::wasi::ffi::{OsStrExt, OsStringExt} with the same
as_bytes()/from_bytes()/into_vec()/from_vec() API as Unix. Without this,
os_str_as_bytes() fell into the not(unix) path requiring UTF-8 validation
via to_str(), causing failures like:
  echo '🍎,🍌,🍒,🥝' => "invalid UTF-8 input encountered"
---
 src/uucore/src/lib/lib.rs | 30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/src/uucore/src/lib/lib.rs b/src/uucore/src/lib/lib.rs
index 4b2cb9b50..275486889 100644
--- a/src/uucore/src/lib/lib.rs
+++ b/src/uucore/src/lib/lib.rs
@@ -142,6 +142,8 @@ use std::io::{BufRead, BufReader};
 use std::iter;
 #[cfg(unix)]
 use std::os::unix::ffi::{OsStrExt, OsStringExt};
+#[cfg(target_os = "wasi")]
+use std::os::wasi::ffi::{OsStrExt, OsStringExt};
 use std::str;
 use std::str::Utf8Chunk;
 use std::sync::{LazyLock, atomic::Ordering};
@@ -434,12 +436,12 @@ impl error::UError for NonUtf8OsStrError {}
 ///
 /// This always succeeds on unix platforms,
 /// and fails on other platforms if the string can't be coerced to UTF-8.
-#[cfg_attr(unix, expect(clippy::unnecessary_wraps))]
+#[cfg_attr(any(unix, target_os = "wasi"), expect(clippy::unnecessary_wraps))]
 pub fn os_str_as_bytes(os_string: &OsStr) -> Result<&[u8], NonUtf8OsStrError> {
-    #[cfg(unix)]
+    #[cfg(any(unix, target_os = "wasi"))]
     return Ok(os_string.as_bytes());
 
-    #[cfg(not(unix))]
+    #[cfg(not(any(unix, target_os = "wasi")))]
     os_string
         .to_str()
         .ok_or_else(|| NonUtf8OsStrError {
@@ -453,10 +455,10 @@ pub fn os_str_as_bytes(os_string: &OsStr) -> Result<&[u8], NonUtf8OsStrError> {
 /// This is always lossless on unix platforms,
 /// and wraps [`OsStr::to_string_lossy`] on non-unix platforms.
 pub fn os_str_as_bytes_lossy(os_string: &OsStr) -> Cow<'_, [u8]> {
-    #[cfg(unix)]
+    #[cfg(any(unix, target_os = "wasi"))]
     return Cow::from(os_string.as_bytes());
 
-    #[cfg(not(unix))]
+    #[cfg(not(any(unix, target_os = "wasi")))]
     match os_string.to_string_lossy() {
         Cow::Borrowed(slice) => Cow::from(slice.as_bytes()),
         Cow::Owned(owned) => Cow::from(owned.into_bytes()),
@@ -468,12 +470,12 @@ pub fn os_str_as_bytes_lossy(os_string: &OsStr) -> Cow<'_, [u8]> {
 ///
 /// This always succeeds on unix platforms,
 /// and fails on other platforms if the bytes can't be parsed as UTF-8.
-#[cfg_attr(unix, expect(clippy::unnecessary_wraps))]
+#[cfg_attr(any(unix, target_os = "wasi"), expect(clippy::unnecessary_wraps))]
 pub fn os_str_from_bytes(bytes: &[u8]) -> error::UResult<Cow<'_, OsStr>> {
-    #[cfg(unix)]
+    #[cfg(any(unix, target_os = "wasi"))]
     return Ok(Cow::Borrowed(OsStr::from_bytes(bytes)));
 
-    #[cfg(not(unix))]
+    #[cfg(not(any(unix, target_os = "wasi")))]
     Ok(Cow::Owned(OsString::from(str::from_utf8(bytes).map_err(
         |_| error::UUsageError::new(1, "Unable to transform bytes into OsStr"),
     )?)))
@@ -483,12 +485,12 @@ pub fn os_str_from_bytes(bytes: &[u8]) -> error::UResult<Cow<'_, OsStr>> {
 ///
 /// This always succeeds on unix platforms,
 /// and fails on other platforms if the bytes can't be parsed as UTF-8.
-#[cfg_attr(unix, expect(clippy::unnecessary_wraps))]
+#[cfg_attr(any(unix, target_os = "wasi"), expect(clippy::unnecessary_wraps))]
 pub fn os_string_from_vec(vec: Vec<u8>) -> error::UResult<OsString> {
-    #[cfg(unix)]
+    #[cfg(any(unix, target_os = "wasi"))]
     return Ok(OsString::from_vec(vec));
 
-    #[cfg(not(unix))]
+    #[cfg(not(any(unix, target_os = "wasi")))]
     Ok(OsString::from(String::from_utf8(vec).map_err(|_| {
         error::UUsageError::new(1, "invalid UTF-8 was detected in one or more arguments")
     })?))
@@ -498,11 +500,11 @@ pub fn os_string_from_vec(vec: Vec<u8>) -> error::UResult<OsString> {
 ///
 /// This always succeeds on unix platforms,
 /// and fails on other platforms if the bytes can't be parsed as UTF-8.
-#[cfg_attr(unix, expect(clippy::unnecessary_wraps))]
+#[cfg_attr(any(unix, target_os = "wasi"), expect(clippy::unnecessary_wraps))]
 pub fn os_string_to_vec(s: OsString) -> error::UResult<Vec<u8>> {
-    #[cfg(unix)]
+    #[cfg(any(unix, target_os = "wasi"))]
     let v = s.into_vec();
-    #[cfg(not(unix))]
+    #[cfg(not(any(unix, target_os = "wasi")))]
     let v = s
         .into_string()
         .map_err(|_| {