Quote virtual environment activation paths with shell metacharacters

crates/uv-shell/src/shlex.rs

@@ -6,13 +6,15 @@ pub fn shlex_posix(executable: impl AsRef<Path>) -> String {
     // Convert to a display path.
     let executable = executable.as_ref().portable_display().to_string();
 
-    // Like Python's `shlex.quote`:
-    // > Use single quotes, and put single quotes into double quotes
-    // > The string $'b is then quoted as '$'"'"'b'
-    if executable.contains(' ') {
-        format!("'{}'", escape_posix_for_single_quotes(&executable))
-    } else {
+    // Match Python's `shlex.quote` and leave only shell-safe ASCII characters unquoted.
+    if !executable.is_empty()
+        && executable
+            .bytes()
+            .all(|byte| byte.is_ascii_alphanumeric() || b"@%+=:,./-_".contains(&byte))
+    {
         executable
+    } else {
+        format!("'{}'", escape_posix_for_single_quotes(&executable))
     }
 }
 
@@ -48,3 +50,26 @@ pub fn shlex_windows(executable: impl AsRef<Path>, shell: Shell) -> String {
         executable
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::shlex_posix;
+
+    #[test]
+    fn posix_safe_path() {
+        assert_eq!(shlex_posix("/usr/bin/python3.12"), "/usr/bin/python3.12");
+    }
+
+    #[test]
+    fn posix_empty_path() {
+        assert_eq!(shlex_posix(""), "''");
+    }
+
+    #[test]
+    fn posix_path_with_metacharacters() {
+        assert_eq!(
+            shlex_posix("Testing's/$venv;activate"),
+            r#"'Testing'"'"'s/$venv;activate'"#
+        );
+    }
+}

crates/uv/tests/python/venv.rs

@@ -1610,7 +1610,7 @@ fn create_venv_apostrophe() {
     ----- stderr -----
     Using CPython 3.12.[X] interpreter at: [PYTHON-3.12]
     Creating virtual environment at: Testing's
-    Activate with: source Testing's/[BIN]/activate
+    Activate with: source 'Testing'\"'\"'s/[BIN]/activate'
     "
     );