fix: harden the observability fields against the verifier findings

tests/integration/test_postgres_telemetry.py

@@ -119,6 +119,105 @@ async def _fetch(dsn: str, sql: str, *args):
         await conn.close()
 
 
+_LEGACY_DDL = """
+CREATE TABLE {schema}.llm_calls (
+    call_id            TEXT PRIMARY KEY,
+    parent_call_id     TEXT,
+    session_id         TEXT,
+    model              TEXT NOT NULL,
+    provider           TEXT NOT NULL,
+    source_name        TEXT NOT NULL,
+    messages           TEXT NOT NULL,
+    response           TEXT NOT NULL,
+    thinking           TEXT NOT NULL DEFAULT '',
+    prompt_tokens      INTEGER NOT NULL,
+    completion_tokens  INTEGER NOT NULL,
+    usage_source       TEXT NOT NULL,
+    latency_ms         INTEGER NOT NULL,
+    ttft_ms            DOUBLE PRECISION,
+    max_inter_token_ms DOUBLE PRECISION,
+    cache_hit          BOOLEAN NOT NULL DEFAULT FALSE,
+    error              TEXT,
+    cost               DOUBLE PRECISION,
+    created_at         TIMESTAMPTZ NOT NULL DEFAULT now()
+)
+"""
+
+
+@pytest.fixture
+async def legacy_schema(dsn):
+    """在**自建的临时 schema** 里造一张 18 列旧表,验证补列(issue #3)。
+
+    绝不碰共享的 public.llm_calls: 用 search_path 把 recorder 指向临时 schema,
+    teardown 只 DROP 自己建的 schema。
+    """
+    import asyncpg
+
+    name = f"pgwtest_{uuid4().hex[:8]}"
+    conn = await asyncpg.connect(dsn, timeout=10)
+    try:
+        await conn.execute(f"CREATE SCHEMA {name}")
+        await conn.execute(_LEGACY_DDL.format(schema=name))
+    finally:
+        await conn.close()
+    sep = "&" if "?" in dsn else "?"
+    yield f"{dsn}{sep}options=-csearch_path%3D{name}", name
+    conn = await asyncpg.connect(dsn, timeout=10)
+    try:
+        await conn.execute(f"DROP SCHEMA {name} CASCADE")
+    finally:
+        await conn.close()
+
+
+class TestObservabilityColumns:
+    """issue #3: 两列写入可回读,且已存在的 18 列旧表会被自动补列。"""
+
+    async def test_values_round_trip(self, dsn):
+        recorder = PostgresRecorder(dsn)
+        try:
+            await _record_minimal(recorder, call_id=_cid("hit"), cached_prompt_tokens=64)
+            await _record_minimal(recorder, call_id=_cid("zero"), cached_prompt_tokens=0)
+            await _record_minimal(recorder, call_id=_cid("model"), model_reported="MiniMax-01")
+            rows = await _fetch(
+                dsn,
+                "SELECT call_id, cached_prompt_tokens, model_reported FROM llm_calls "
+                "WHERE call_id LIKE $1",
+                f"{_RUN_PREFIX}-%",
+            )
+            by_id = {r["call_id"]: r for r in rows}
+            assert by_id[_cid("hit")]["cached_prompt_tokens"] == 64
+            assert by_id[_cid("zero")]["cached_prompt_tokens"] == 0  # 真实零命中 ≠ NULL
+            assert by_id[_cid("model")]["cached_prompt_tokens"] is None
+            assert by_id[_cid("model")]["model_reported"] == "MiniMax-01"
+        finally:
+            await recorder.aclose()
+
+    async def test_legacy_table_is_upgraded_in_place(self, legacy_schema):
+        """18 列旧表不补列的话,每行写入都会被逐行 warning 丢弃(遥测静默全失)。"""
+        schema_dsn, schema = legacy_schema
+        recorder = PostgresRecorder(schema_dsn)
+        try:
+            await _record_minimal(
+                recorder, call_id=_cid("legacy"), cached_prompt_tokens=7, model_reported="m-real"
+            )
+            cols = await _fetch(
+                schema_dsn,
+                "SELECT column_name FROM information_schema.columns "
+                "WHERE table_schema = $1 AND table_name = 'llm_calls' ORDER BY ordinal_position",
+                schema,
+            )
+            # ALTER 只能追加到末尾: 与新建库的列序一致才不会分叉
+            assert [r["column_name"] for r in cols] == _EXPECTED_COLUMNS
+            rows = await _fetch(
+                schema_dsn,
+                "SELECT cached_prompt_tokens, model_reported FROM llm_calls WHERE call_id = $1",
+                _cid("legacy"),
+            )
+            assert (rows[0]["cached_prompt_tokens"], rows[0]["model_reported"]) == (7, "m-real")
+        finally:
+            await recorder.aclose()
+
+
 class TestSchema:
     async def test_schema_has_frozen_columns_in_order(self, dsn):
         recorder = PostgresRecorder(dsn)

tests/unit/test_openai_compat.py

@@ -360,6 +360,19 @@ class TestObservabilityFields:
         result = await _complete(_transport_for(handler), _source())
         assert result.model_reported == "MiniMax-Text-01-250321"
 
+    async def test_empty_first_model_does_not_block_a_later_real_one(self):
+        """首帧报空串不得锁死 sink: 守卫按"有效值"判断,否则真实版本会丢。"""
+
+        def handler(request):
+            return _sse_stream(
+                _chunk(content="a", model=""),
+                _chunk(content="b", model="MiniMax-Text-01-250321"),
+                _chunk(usage=_USAGE),
+            )
+
+        result = await _complete(_transport_for(handler), _source())
+        assert result.model_reported == "MiniMax-Text-01-250321"
+
     @pytest.mark.parametrize("bad", [None, "", "   ", 123, {}])
     async def test_missing_or_malformed_model_is_none(self, bad):
         def handler(request):

tests/unit/test_pricing.py

@@ -77,6 +77,10 @@ class TestCachedInputTier:
     def test_no_hit_is_billed_in_full(self, cached):
         assert self._CACHED.cost("m", 1_000_000, 0, cached) == pytest.approx(10.0)
 
+    def test_negative_cached_is_billed_in_full(self):
+        """负数命中数不得抬高成本: cost() 是公共方法,外部输入须校验后使用(P5)。"""
+        assert self._CACHED.cost("m", 1_000_000, 0, -500_000) == pytest.approx(10.0)
+
     def test_cached_over_prompt_is_clamped_and_never_negative(self):
         """网关口径异常时按输入总数夹取: 全部按缓存价,不得算出负成本。"""
         clamped = self._CACHED.cost("m", 1_000_000, 0, 5_000_000)

tests/unit/test_telemetry.py

@@ -202,8 +202,9 @@ class TestSQLiteColumnBackfill:
     async def test_backfill_failure_keeps_the_recorder_usable(self, tmp_path):
         """补列失败只能逐行降级,绝不能把 recorder 整体变成 no-op(设计 D1 纪律)。
 
-        把 llm_calls 建成 view: 表不存在故 CREATE TABLE IF NOT EXISTS 会撞名失败,
-        ALTER 也无从谈起——这是最坏路径。
+        把 llm_calls 建成同名 view: `CREATE TABLE IF NOT EXISTS` 遇 view 静默
+        no-op(不抛),随后的 ALTER 才抛 "Cannot add a column to a view"——正是
+        补列失败这条分支。`_conn` 必须保持非 None,否则整个 recorder 永久失能。
         """
         db = tmp_path / "view.db"
         conn = sqlite3.connect(db)
@@ -213,6 +214,7 @@ class TestSQLiteColumnBackfill:
         conn.close()
 
         recorder = SQLiteRecorder(db)  # 不得抛
+        assert recorder._conn is not None  # 补列失败 ≠ recorder 失能(D1 纪律)
         await _record_minimal(recorder)  # 不得抛
         recorder.close()