fix: keep truncated session history tool-call consistent

tests/test_session_manager_history.py

@@ -1,52 +1,146 @@
 from nanobot.session.manager import Session
 
 
+def _assert_no_orphans(history: list[dict]) -> None:
+    """Assert every tool result in history has a matching assistant tool_call."""
+    declared = {
+        tc["id"]
+        for m in history if m.get("role") == "assistant"
+        for tc in (m.get("tool_calls") or [])
+    }
+    orphans = [
+        m.get("tool_call_id") for m in history
+        if m.get("role") == "tool" and m.get("tool_call_id") not in declared
+    ]
+    assert orphans == [], f"orphan tool_call_ids: {orphans}"
+
+
+def _tool_turn(prefix: str, idx: int) -> list[dict]:
+    """Helper: one assistant with 2 tool_calls + 2 tool results."""
+    return [
+        {
+            "role": "assistant",
+            "content": None,
+            "tool_calls": [
+                {"id": f"{prefix}_{idx}_a", "type": "function", "function": {"name": "x", "arguments": "{}"}},
+                {"id": f"{prefix}_{idx}_b", "type": "function", "function": {"name": "y", "arguments": "{}"}},
+            ],
+        },
+        {"role": "tool", "tool_call_id": f"{prefix}_{idx}_a", "name": "x", "content": "ok"},
+        {"role": "tool", "tool_call_id": f"{prefix}_{idx}_b", "name": "y", "content": "ok"},
+    ]
+
+
+# --- Original regression test (from PR 2075) ---
+
 def test_get_history_drops_orphan_tool_results_when_window_cuts_tool_calls():
     session = Session(key="telegram:test")
     session.messages.append({"role": "user", "content": "old turn"})
-
     for i in range(20):
-        session.messages.append(
-            {
-                "role": "assistant",
-                "content": None,
-                "tool_calls": [
-                    {"id": f"old_{i}_a", "type": "function", "function": {"name": "x", "arguments": "{}"}},
-                    {"id": f"old_{i}_b", "type": "function", "function": {"name": "y", "arguments": "{}"}},
-                ],
-            }
-        )
-        session.messages.append({"role": "tool", "tool_call_id": f"old_{i}_a", "name": "x", "content": "ok"})
-        session.messages.append({"role": "tool", "tool_call_id": f"old_{i}_b", "name": "y", "content": "ok"})
-
+        session.messages.extend(_tool_turn("old", i))
     session.messages.append({"role": "user", "content": "problem turn"})
     for i in range(25):
-        session.messages.append(
-            {
-                "role": "assistant",
-                "content": None,
-                "tool_calls": [
-                    {"id": f"cur_{i}_a", "type": "function", "function": {"name": "x", "arguments": "{}"}},
-                    {"id": f"cur_{i}_b", "type": "function", "function": {"name": "y", "arguments": "{}"}},
-                ],
-            }
-        )
-        session.messages.append({"role": "tool", "tool_call_id": f"cur_{i}_a", "name": "x", "content": "ok"})
-        session.messages.append({"role": "tool", "tool_call_id": f"cur_{i}_b", "name": "y", "content": "ok"})
-
+        session.messages.extend(_tool_turn("cur", i))
     session.messages.append({"role": "user", "content": "new telegram question"})
 
     history = session.get_history(max_messages=100)
-    assistant_ids = {
-        tool_call["id"]
-        for message in history
-        if message.get("role") == "assistant"
-        for tool_call in (message.get("tool_calls") or [])
-    }
-    orphan_tool_ids = [
-        message.get("tool_call_id")
-        for message in history
-        if message.get("role") == "tool" and message.get("tool_call_id") not in assistant_ids
-    ]
+    _assert_no_orphans(history)
 
-    assert orphan_tool_ids == []
+
+# --- Positive test: legitimate pairs survive trimming ---
+
+def test_legitimate_tool_pairs_preserved_after_trim():
+    """Complete tool-call groups within the window must not be dropped."""
+    session = Session(key="test:positive")
+    session.messages.append({"role": "user", "content": "hello"})
+    for i in range(5):
+        session.messages.extend(_tool_turn("ok", i))
+    session.messages.append({"role": "assistant", "content": "done"})
+
+    history = session.get_history(max_messages=500)
+    _assert_no_orphans(history)
+    tool_ids = [m["tool_call_id"] for m in history if m.get("role") == "tool"]
+    assert len(tool_ids) == 10
+    assert history[0]["role"] == "user"
+
+
+# --- last_consolidated > 0 ---
+
+def test_orphan_trim_with_last_consolidated():
+    """Orphan trimming works correctly when session is partially consolidated."""
+    session = Session(key="test:consolidated")
+    for i in range(10):
+        session.messages.append({"role": "user", "content": f"old {i}"})
+        session.messages.extend(_tool_turn("cons", i))
+    session.last_consolidated = 30
+
+    session.messages.append({"role": "user", "content": "recent"})
+    for i in range(15):
+        session.messages.extend(_tool_turn("new", i))
+    session.messages.append({"role": "user", "content": "latest"})
+
+    history = session.get_history(max_messages=20)
+    _assert_no_orphans(history)
+    assert all(m.get("role") != "tool" or m["tool_call_id"].startswith("new_") for m in history)
+
+
+# --- Edge: no tool messages at all ---
+
+def test_no_tool_messages_unchanged():
+    session = Session(key="test:plain")
+    for i in range(5):
+        session.messages.append({"role": "user", "content": f"q{i}"})
+        session.messages.append({"role": "assistant", "content": f"a{i}"})
+
+    history = session.get_history(max_messages=6)
+    assert len(history) == 6
+    _assert_no_orphans(history)
+
+
+# --- Edge: all leading messages are orphan tool results ---
+
+def test_all_orphan_prefix_stripped():
+    """If the window starts with orphan tool results and nothing else, they're all dropped."""
+    session = Session(key="test:all-orphan")
+    session.messages.append({"role": "tool", "tool_call_id": "gone_1", "name": "x", "content": "ok"})
+    session.messages.append({"role": "tool", "tool_call_id": "gone_2", "name": "y", "content": "ok"})
+    session.messages.append({"role": "user", "content": "fresh start"})
+    session.messages.append({"role": "assistant", "content": "hi"})
+
+    history = session.get_history(max_messages=500)
+    _assert_no_orphans(history)
+    assert history[0]["role"] == "user"
+    assert len(history) == 2
+
+
+# --- Edge: empty session ---
+
+def test_empty_session_history():
+    session = Session(key="test:empty")
+    history = session.get_history(max_messages=500)
+    assert history == []
+
+
+# --- Window cuts mid-group: assistant present but some tool results orphaned ---
+
+def test_window_cuts_mid_tool_group():
+    """If the window starts between an assistant's tool results, the partial group is trimmed."""
+    session = Session(key="test:mid-cut")
+    session.messages.append({"role": "user", "content": "setup"})
+    session.messages.append({
+        "role": "assistant", "content": None,
+        "tool_calls": [
+            {"id": "split_a", "type": "function", "function": {"name": "x", "arguments": "{}"}},
+            {"id": "split_b", "type": "function", "function": {"name": "y", "arguments": "{}"}},
+        ],
+    })
+    session.messages.append({"role": "tool", "tool_call_id": "split_a", "name": "x", "content": "ok"})
+    session.messages.append({"role": "tool", "tool_call_id": "split_b", "name": "y", "content": "ok"})
+    session.messages.append({"role": "user", "content": "next"})
+    session.messages.extend(_tool_turn("intact", 0))
+    session.messages.append({"role": "assistant", "content": "final"})
+
+    # Window of 6 should cut off the "setup" user msg and the assistant with split_a/split_b,
+    # leaving orphan tool results for split_a at the front.
+    history = session.get_history(max_messages=6)
+    _assert_no_orphans(history)