Phase 7: Directory restructuring (messaging/ and tests/)

- Create messaging/platforms/ (base, discord, telegram, factory)
- Create messaging/rendering/ (discord_markdown, telegram_markdown)
- Create messaging/trees/ (data, repository, processor, queue_manager)
- Organize tests/ into api/, providers/, messaging/, cli/, config/
- Add backward-compatible re-exports at old locations
- Update handler.py and test_messaging_factory.py imports
- Fix Telegram type hints for TELEGRAM_AVAILABLE=False case
- Fix Python 3 except syntax in discord_markdown

Co-authored-by: Ali Khokhar <alishahryar2@gmail.com>

tests/messaging/test_handler_context_isolation.py

@@ -0,0 +1,157 @@
+import pytest
+from unittest.mock import AsyncMock, MagicMock
+
+from messaging.handler import ClaudeMessageHandler
+from messaging.tree_data import MessageState
+
+
+async def _gen_session(events):
+    for e in events:
+        yield e
+
+
+@pytest.fixture
+def handler(mock_platform, mock_cli_manager, mock_session_store):
+    return ClaudeMessageHandler(mock_platform, mock_cli_manager, mock_session_store)
+
+
+@pytest.mark.asyncio
+async def test_sibling_replies_fork_from_parent_session_id(
+    handler, mock_cli_manager, incoming_message_factory
+):
+    # Root node A with a known session_id.
+    root_incoming = incoming_message_factory(text="A", message_id="A")
+    tree = await handler.tree_queue.create_tree(
+        node_id="A", incoming=root_incoming, status_message_id="status_A"
+    )
+    await tree.update_state("A", MessageState.COMPLETED, session_id="sess_A")
+
+    # Add two sibling replies R1 and R2 under A.
+    r1_incoming = incoming_message_factory(
+        text="R1", message_id="R1", reply_to_message_id="A"
+    )
+    r2_incoming = incoming_message_factory(
+        text="R2", message_id="R2", reply_to_message_id="A"
+    )
+    _, r1_node = await handler.tree_queue.add_to_tree(
+        "A", "R1", r1_incoming, "status_R1"
+    )
+    _, r2_node = await handler.tree_queue.add_to_tree(
+        "A", "R2", r2_incoming, "status_R2"
+    )
+
+    # Mock a fresh cli_session per node.
+    calls = []
+
+    async def _get_or_create_session(session_id=None):
+        cli_session = MagicMock()
+
+        async def _start_task(prompt, session_id=None, fork_session=False):
+            calls.append((prompt, session_id, fork_session))
+            child_sid = f"sess_{prompt}"
+            async for ev in _gen_session(
+                [
+                    {"type": "session_info", "session_id": child_sid},
+                    {"type": "exit", "code": 0, "stderr": None},
+                ]
+            ):
+                yield ev
+
+        cli_session.start_task = _start_task
+        return cli_session, f"pending_{len(calls) + 1}", True
+
+    mock_cli_manager.get_or_create_session = AsyncMock(
+        side_effect=_get_or_create_session
+    )
+
+    await handler._process_node("R1", r1_node)
+    await handler._process_node("R2", r2_node)
+
+    # Both siblings must resume from the same parent session and fork.
+    assert calls[0][0] == "R1"
+    assert calls[0][1] == "sess_A"
+    assert calls[0][2] is True
+
+    assert calls[1][0] == "R2"
+    assert calls[1][1] == "sess_A"
+    assert calls[1][2] is True
+
+
+@pytest.mark.asyncio
+async def test_grandchild_reply_forks_from_branch_session(
+    handler, mock_cli_manager, incoming_message_factory
+):
+    root_incoming = incoming_message_factory(text="A", message_id="A")
+    tree = await handler.tree_queue.create_tree(
+        node_id="A", incoming=root_incoming, status_message_id="status_A"
+    )
+    await tree.update_state("A", MessageState.COMPLETED, session_id="sess_A")
+
+    r1_incoming = incoming_message_factory(
+        text="R1", message_id="R1", reply_to_message_id="A"
+    )
+    _, r1_node = await handler.tree_queue.add_to_tree(
+        "A", "R1", r1_incoming, "status_R1"
+    )
+
+    calls = []
+
+    async def _get_or_create_session(session_id=None):
+        cli_session = MagicMock()
+
+        async def _start_task(prompt, session_id=None, fork_session=False):
+            calls.append((prompt, session_id, fork_session))
+            # R1 gets its own forked session id.
+            child_sid = "sess_R1"
+            async for ev in _gen_session(
+                [
+                    {"type": "session_info", "session_id": child_sid},
+                    {"type": "exit", "code": 0, "stderr": None},
+                ]
+            ):
+                yield ev
+
+        cli_session.start_task = _start_task
+        return cli_session, "pending_R1", True
+
+    mock_cli_manager.get_or_create_session = AsyncMock(
+        side_effect=_get_or_create_session
+    )
+
+    await handler._process_node("R1", r1_node)
+    assert r1_node.session_id == "sess_R1"
+
+    # Grandchild C1 replies to R1 and must fork from sess_R1, not sess_A.
+    c1_incoming = incoming_message_factory(
+        text="C1", message_id="C1", reply_to_message_id="R1"
+    )
+    _, c1_node = await handler.tree_queue.add_to_tree(
+        "R1", "C1", c1_incoming, "status_C1"
+    )
+
+    async def _get_or_create_session_c1(session_id=None):
+        cli_session = MagicMock()
+
+        async def _start_task(prompt, session_id=None, fork_session=False):
+            calls.append((prompt, session_id, fork_session))
+            async for ev in _gen_session(
+                [
+                    {"type": "session_info", "session_id": "sess_C1"},
+                    {"type": "exit", "code": 0, "stderr": None},
+                ]
+            ):
+                yield ev
+
+        cli_session.start_task = _start_task
+        return cli_session, "pending_C1", True
+
+    mock_cli_manager.get_or_create_session = AsyncMock(
+        side_effect=_get_or_create_session_c1
+    )
+
+    await handler._process_node("C1", c1_node)
+
+    # The last call should be for C1 and must resume from sess_R1.
+    assert calls[-1][0] == "C1"
+    assert calls[-1][1] == "sess_R1"
+    assert calls[-1][2] is True