llm_client: 진짜 JSON 앞에 군더더기 { 한 줄이 붙은 응답 처리 (고객사 실측)

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

tests/test_llm_backends.py

@@ -303,3 +303,16 @@ def test_extract_json_dumps_unreadable_content(tmp_path, monkeypatch):
         _extract_json("안녕하세요! 반갑습니다.")
     dumped = list((tmp_path / "_badjson").glob("*.txt"))
     assert len(dumped) == 1 and "안녕하세요" in dumped[0].read_text(encoding="utf-8")
+
+
+def test_extract_json_skips_stray_opening_brace(tmp_path, monkeypatch):
+    """고객사 실측: `{` 한 줄 뒤에 진짜 JSON (Expecting property name enclosed in double quotes: line 2 column 1)."""
+    from config.settings import settings
+    monkeypatch.setattr(settings, "data_llm_jobs", tmp_path)
+    assert _extract_json('{\n{"program": "ZRMEM2016", "business_purpose_ko": "요약"}') == {
+        "program": "ZRMEM2016", "business_purpose_ko": "요약"}
+    # 군더더기 { + 값 안 따옴표까지 같이 틀린 경우
+    assert _extract_json('{\n{"program": "Z1", "x": "a "b" c"}')["x"] == 'a "b" c'
+    # 서문 + 객체 두 개면 첫 번째 완전한 객체
+    assert _extract_json('결과:\n{"a": 1}\n{"b": 2}') == {"a": 1}
+    assert not list((tmp_path / "_badjson").glob("*")) if (tmp_path / "_badjson").exists() else True