Commit c90aa996b for llama.cpp

commit c90aa996bab649751c065a7a27b77f53f5141e66
Author: Vladimir Sotnikov <bubert9@gmail.com>
Date:   Tue Nov 10 09:56:53 2026 +0200

    common : escape control characters in tool argument strings (#31937)

    normalize_quotes_to_json copies raw control characters verbatim while
    converting pythonic tool arguments to JSON, so calls like
    python(code='a<LF>b') produce invalid JSON in the arguments returned to
    clients; replaying that history then fails hard. Escape C0 control
    characters inside quoted strings via escape_json_string_inner.

diff --git a/common/chat-peg-parser.cpp b/common/chat-peg-parser.cpp
index 21620a7a4..4440b2ebd 100644
--- a/common/chat-peg-parser.cpp
+++ b/common/chat-peg-parser.cpp
@@ -131,6 +131,12 @@ static std::string normalize_quotes_to_json(const std::string & input) {
             continue;
         }

+        // Models can emit raw control characters inside string literals; escape them to keep the JSON valid.
+        if ((in_single_quoted || in_double_quoted) && static_cast<unsigned char>(c) < 0x20) {
+            result += escape_json_string_inner(std::string(1, c));
+            continue;
+        }
+
         // Handle quote characters
         if (c == '"') {
             if (in_single_quoted) {
diff --git a/tests/test-chat.cpp b/tests/test-chat.cpp
index 57955b983..a583604a7 100644
--- a/tests/test-chat.cpp
+++ b/tests/test-chat.cpp
@@ -2160,6 +2160,12 @@ static void test_lfm2_parser(const std::string & template_path, bool detailed_de
         })
         .run();

+    // Raw control characters in pythonic string arguments must be escaped into valid JSON.
+    tst.test("<|tool_call_start|>[python(code='a\nb')]<|tool_call_end|>")
+        .tools({ python_tool })
+        .expect_tool_calls({ { "python", R"#({"code": "a\nb"})#", "" } })
+        .run();
+
     // String escape sequences decode to their actual characters (newline + tab here),
     // so a "write a two line file" style call produces real line breaks, not literal "\n".
     tst.test("<|tool_call_start|>[python(code=\"First line\\nSecond line\\tindented\")]<|tool_call_end|>")