From e1c6be0682b795862d4105da91f7c15b97ceaeb4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andreas=20K=C3=A4llberg?= <anka.213@gmail.com>
Date: Wed, 20 Sep 2023 18:04:28 +0200
Subject: [PATCH] Fix tilde-expansion for multi-byte unicode chars (#10434)

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# Description
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Fixes #10365

Use bytes() instead of chars() to get an actual index that can be used
with file.split_at(). utf8 is safe to process bytewise, since an ascii
character can never be mistaken for a non-ascii character


# User-Facing Changes
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# Tests + Formatting

- [x] Don't forget to add tests that cover your changes.

Make sure you've run and fixed any issues with these commands:

- [x] `cargo fmt --all -- --check` to check standard code formatting
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- [x] `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used`
to check that you're using the standard code style
- [x] `cargo test --workspace` to check that all tests pass (on Windows
make sure to [enable developer
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---
 crates/nu-path/src/tilde.rs | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/crates/nu-path/src/tilde.rs b/crates/nu-path/src/tilde.rs
index 48c43a74a2..b7df144237 100644
--- a/crates/nu-path/src/tilde.rs
+++ b/crates/nu-path/src/tilde.rs
@@ -22,9 +22,9 @@ fn expand_tilde_with_home(path: impl AsRef<Path>, home: Option<PathBuf>) -> Path
 
     if !path.starts_with("~") {
         let string = path.to_string_lossy();
-        let mut path_as_string = string.as_ref().chars();
+        let mut path_as_string = string.as_ref().bytes();
         return match path_as_string.next() {
-            Some('~') => expand_tilde_with_another_user_home(path),
+            Some(b'~') => expand_tilde_with_another_user_home(path),
             _ => path.into(),
         };
     }
@@ -121,7 +121,7 @@ fn expand_tilde_with_another_user_home(path: &Path) -> PathBuf {
     return match path.to_str() {
         Some(file_path) => {
             let mut file = file_path.to_string();
-            match file_path.chars().position(|c| c == '/' || c == '\\') {
+            match file_path.find(|c| c == '/' || c == '\\') {
                 None => {
                     file.remove(0);
                     user_home_dir(&file)
@@ -185,6 +185,22 @@ mod tests {
         check_expanded("~//test/");
     }
 
+    #[test]
+    fn string_with_tilde_other_user() {
+        let s = "~someone/test/";
+        let expected = format!("{FALLBACK_USER_HOME_BASE_DIR}/someone/test/");
+
+        assert_eq!(expand_tilde(Path::new(s)), PathBuf::from(expected));
+    }
+
+    #[test]
+    fn string_with_multi_byte_chars() {
+        let s = "~あ/";
+        let expected = format!("{FALLBACK_USER_HOME_BASE_DIR}/あ/");
+
+        assert_eq!(expand_tilde(Path::new(s)), PathBuf::from(expected));
+    }
+
     #[test]
     fn does_not_expand_tilde_if_tilde_is_not_first_character() {
         check_not_expanded("1~1");