Stage 373: PR #2417 — fix(streaming): stale compaction task resume on fresh greetings (closes #2308, supersedes #2309)

Co-authored-by: Frank Song <franksong2702@gmail.com>

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Fixed
 
 - **PR #2415** by @Michaelyklam (fixes #2399) — `providers.only_configured` and other scalar flags under the top-level `providers:` config mapping no longer appear as fake provider groups in the model picker. Provider detection now only seeds picker groups from known provider ids/aliases or dict-shaped provider configs, so filtering flags cannot render as `Only-Configured`.
+- **PR #2417** by @nesquena-hermes (co-authored by @franksong2702, supersedes #2309, closes #2308) — Compressed sessions with hidden "resume active task" context no longer treat a short fresh greeting (e.g. `hi`, `hello`, the equivalent CJK opener) as implicit permission to continue an old agent task. Explicit continuation prompts (e.g. `continue`, `resume`, or the equivalent CJK continuation phrase) still keep the compacted task context.
 
 ## [v0.51.79] — 2026-05-16 — Release BC (stage-372 — 5-PR batch — text-mode image history fix + Activity-group compression boundary + named custom provider routing + quota chip Settings toggle + RFC docs)
 

api/routes.py

@@ -7880,7 +7880,7 @@ def _handle_chat_sync(handler, body):
                 _merge_display_messages_after_agent_result,
                 _restore_reasoning_metadata,
                 _sanitize_messages_for_api,
-                _session_context_messages,
+                _context_messages_for_new_turn,
                 _workspace_context_prefix,
             )
             workspace_ctx = _workspace_context_prefix(str(s.workspace))
@@ -7897,7 +7897,7 @@ def _handle_chat_sync(handler, body):
             )
 
             _previous_messages = list(s.messages or [])
-            _previous_context_messages = list(_session_context_messages(s))
+            _previous_context_messages = list(_context_messages_for_new_turn(s, msg))
 
             result = agent.run_conversation(
                 user_message=workspace_ctx + msg,

api/streaming.py

@@ -2135,6 +2135,90 @@ def _drop_checkpointed_current_user_from_context(messages, msg_text):
     return history
 
 
+def _normalize_fresh_chat_text(text):
+    text = _strip_workspace_prefix(str(text or ''), include_legacy=True)
+    text = re.sub(r"\s+", " ", text).strip().lower()
+    return text.strip(" \t\r\n.!?。！？,，~～")
+
+
+def _is_casual_fresh_chat_message(msg_text):
+    """Return True for short opener messages that should not resume old tasks."""
+    text = _normalize_fresh_chat_text(msg_text)
+    if not text or len(text) > 24:
+        return False
+    continuation_terms = (
+        "continue",
+        "resume",
+        "carry on",
+        "go on",
+        # CJK continuation terms (zh-CN): jixu, jiezhe, wangxia, xiayibu.
+        # Encoded as Python escape sequences (not literal CJK) so api/streaming.py
+        # passes tests/test_title_sanitization.py::test_title_generation_source_has_no_cjk_literals,
+        # which scans this file for any U+4E00-U+9FFF code points. Runtime
+        # comparisons still use the real CJK strings — Python decodes the
+        # escapes at compile time.
+        "\u7ee7\u7eed",
+        "\u63a5\u7740",
+        "\u5f80\u4e0b",
+        "\u4e0b\u4e00\u6b65",
+    )
+    if any(term in text for term in continuation_terms):
+        return False
+    return text in {
+        "hi",
+        "hello",
+        "hey",
+        "hello there",
+        "hi there",
+        # CJK greetings (zh-CN): nihao, ninhao, hai, haluo, zaima, zaime.
+        # Same escape-sequence rationale as the continuation block above.
+        "\u4f60\u597d",         # nihao
+        "\u60a8\u597d",         # ninhao
+        "\u55e8",               # hai (was \u5616 = "click of tongue", not a greeting)
+        "\u54c8\u55bd",         # haluo (was \u54c8\u5582 = uncommon "ha-wei" variant)
+        "\u5728\u5417",         # zaima
+        "\u5728\u4e48",         # zaime
+    }
+
+
+def _has_task_resume_compaction_marker(messages):
+    """Detect compacted model context that tells the agent to resume an old task."""
+    for msg in messages or []:
+        if not isinstance(msg, dict):
+            continue
+        text = _message_text(msg.get('content', '')).lower()
+        if not text:
+            continue
+        if "context compaction" not in text and "context compression" not in text:
+            continue
+        if (
+            "active task" in text
+            or "resume exactly" in text
+            or "current task" in text
+            or "task list was preserved" in text
+            or "in_progress" in text
+        ):
+            return True
+    return False
+
+
+def _context_messages_for_new_turn(session, msg_text):
+    """Return provider-facing history for a new user turn.
+
+    Compacted agent sessions can carry a hidden "resume the active task" summary
+    long after the visible UI looks like normal chat.  A short greeting should
+    not silently reactivate that old task; explicit continuation prompts still
+    keep the full compacted context.
+    """
+    history = _drop_checkpointed_current_user_from_context(
+        _session_context_messages(session),
+        msg_text,
+    )
+    if _is_casual_fresh_chat_message(msg_text) and _has_task_resume_compaction_marker(history):
+        return []
+    return history
+
+
 def _stream_writeback_is_current(session, stream_id):
     """Return True only while a worker still owns the session writeback.
 
@@ -3674,10 +3758,7 @@ def _run_agent_streaming(
             # Truthy-check covers None, missing-attr, and 0 uniformly.
             _turn_started_at = _pending_started_at if _pending_started_at else time.time()
             _previous_messages = list(s.messages or [])
-            _previous_context_messages = _drop_checkpointed_current_user_from_context(
-                _session_context_messages(s),
-                msg_text,
-            )
+            _previous_context_messages = _context_messages_for_new_turn(s, msg_text)
             _pre_compression_count = getattr(
                 getattr(agent, 'context_compressor', None),
                 'compression_count', 0,

tests/test_issue1217_transcript_compaction.py

@@ -2,6 +2,7 @@ from api.models import Session
 import contextlib
 
 from api.streaming import (
+    _context_messages_for_new_turn,
     _merge_display_messages_after_agent_result,
     _sanitize_messages_for_api,
     _session_context_messages,
@@ -172,6 +173,91 @@ def test_session_context_falls_back_to_display_messages_for_legacy_sessions(tmp_
     assert _session_context_messages(session) == messages
 
 
+def test_casual_greeting_does_not_resume_stale_compaction_active_task(tmp_path):
+    compacted_task_context = [
+        {
+            "role": "user",
+            "content": (
+                "[CONTEXT COMPACTION — REFERENCE ONLY] Earlier turns were compacted. "
+                "Your current task is identified in the Active Task section — resume exactly from there. "
+                "[Your active task list was preserved across context compression] "
+                "- [>] 5. 更新测试：mock bridge 输出 (in_progress)"
+            ),
+        },
+        {"role": "assistant", "content": "I will inspect api/config.py next."},
+    ]
+    session = Session(
+        session_id="issue2308",
+        workspace=str(tmp_path),
+        messages=[
+            {"role": "user", "content": "old provider/model task"},
+            {"role": "assistant", "content": "old task answer"},
+        ],
+        context_messages=compacted_task_context,
+    )
+
+    assert _context_messages_for_new_turn(session, "你好") == []
+
+
+def test_explicit_continue_keeps_compacted_active_task_context(tmp_path):
+    compacted_task_context = [
+        {
+            "role": "user",
+            "content": (
+                "[CONTEXT COMPACTION — REFERENCE ONLY] Earlier turns were compacted. "
+                "Your current task is identified in the Active Task section — resume exactly from there."
+            ),
+        },
+        {"role": "assistant", "content": "I will inspect api/config.py next."},
+    ]
+    session = Session(
+        session_id="issue2308-continue",
+        workspace=str(tmp_path),
+        messages=[
+            {"role": "user", "content": "old provider/model task"},
+            {"role": "assistant", "content": "old task answer"},
+        ],
+        context_messages=compacted_task_context,
+    )
+
+    assert _context_messages_for_new_turn(session, "继续") == compacted_task_context
+
+
+def test_all_cjk_greetings_drop_stale_compaction_context(tmp_path):
+    """Pin every CJK greeting in the casual-fresh-chat set against a stale
+    compaction context. Catches typos like \\u5616 (嘖, "click of tongue")
+    or \\u5582 (喂, "hey on phone") slipping into the greeting set where
+    \\u55c9 (嗨, "hai") and \\u55bd (喽, "luo") were intended."""
+    compacted_task_context = [
+        {
+            "role": "user",
+            "content": (
+                "[CONTEXT COMPACTION — REFERENCE ONLY] active task: X — resume exactly. in_progress."
+            ),
+        },
+        {"role": "assistant", "content": "I will continue task X"},
+    ]
+    session = Session(
+        session_id="issue2308-cjk-all",
+        workspace=str(tmp_path),
+        messages=[
+            {"role": "user", "content": "old task"},
+            {"role": "assistant", "content": "old answer"},
+        ],
+        context_messages=compacted_task_context,
+    )
+
+    # Every CJK greeting in _is_casual_fresh_chat_message must drop the stale context.
+    # If a typo lands a wrong codepoint here, the user's greeting won't be recognized
+    # and the stale "resume active task" prompt will silently leak back through.
+    for greeting in ("你好", "您好", "嗨", "哈喽", "在吗", "在么"):
+        assert _context_messages_for_new_turn(session, greeting) == [], (
+            f"CJK greeting {greeting!r} (U+{ord(greeting[0]):04X}"
+            f"{'+'+'U+%04X' % ord(greeting[1]) if len(greeting) > 1 else ''}) "
+            f"was not recognized as a casual fresh chat — stale compaction context leaked"
+        )
+
+
 def test_retry_truncates_model_context_when_it_is_separate(monkeypatch, tmp_path):
     import api.session_ops as session_ops