runner: preserve UTF-8 in text-merge normalization

src/runner/modes/common_util/resolve/strip/merge.rs

@@ -217,8 +217,8 @@ fn normalize_text_for_inline(s: &str) -> String {
     // pattern: `;` followed by optional spaces/newlines then `}`
     // Do a few passes to cover nested cases without regex
     for _ in 0..2 {
-        let mut tmp = String::with_capacity(out.len());
         let bytes = out.as_bytes();
+        let mut tmp: Vec<u8> = Vec::with_capacity(bytes.len());
         let mut i = 0usize;
         while i < bytes.len() {
             if bytes[i] == b';' {
@@ -238,13 +238,25 @@ fn normalize_text_for_inline(s: &str) -> String {
                     continue;
                 }
             }
-            tmp.push(bytes[i] as char);
+            tmp.push(bytes[i]);
             i += 1;
         }
-        out = tmp;
+        out = String::from_utf8(tmp).expect("normalize_text_for_inline: invalid UTF-8");
     }
     if !out.ends_with('\n') {
         out.push('\n');
     }
     out
 }
+
+#[cfg(test)]
+mod tests {
+    use super::normalize_text_for_inline;
+
+    #[test]
+    fn normalize_text_for_inline_preserves_utf8() {
+        let src = "aé𝄞;\n}\n";
+        let out = normalize_text_for_inline(src);
+        assert_eq!(out, "aé𝄞\n}\n");
+    }
+}

tools/smokes/v2/profiles/integration/apps/string_cp_mode_min_vm.sh

@@ -13,7 +13,7 @@ run_case() {
     local expect_len="$2"
 
     set +e
-    OUTPUT=$(timeout "$RUN_TIMEOUT_SECS" env -u NYASH_ROOT NYASH_STR_CP="$mode" "$NYASH_BIN" "$INPUT" 2>&1)
+    OUTPUT=$(timeout "$RUN_TIMEOUT_SECS" env NYASH_STR_CP="$mode" "$NYASH_BIN" "$INPUT" 2>&1)
     EXIT_CODE=$?
     set -e