feat: support ignoring unauthorized gateway DMs (#1919)

Add unauthorized_dm_behavior config (pair|ignore) with global default
and per-platform override. WhatsApp can silently drop unknown DMs
instead of sending pairing codes.

Adapted config bridging to work with gw_data dict (pre-construction)
rather than config object. Dropped implementation plan document.

Co-authored-by: Frederico Ribeiro <fr@tecompanytea.com>

tests/gateway/test_config.py

@@ -115,6 +115,22 @@ class TestGatewayConfigRoundtrip:
         assert restored.quick_commands == {"limits": {"type": "exec", "command": "echo ok"}}
         assert restored.group_sessions_per_user is False
 
+    def test_roundtrip_preserves_unauthorized_dm_behavior(self):
+        config = GatewayConfig(
+            unauthorized_dm_behavior="ignore",
+            platforms={
+                Platform.WHATSAPP: PlatformConfig(
+                    enabled=True,
+                    extra={"unauthorized_dm_behavior": "pair"},
+                ),
+            },
+        )
+
+        restored = GatewayConfig.from_dict(config.to_dict())
+
+        assert restored.unauthorized_dm_behavior == "ignore"
+        assert restored.platforms[Platform.WHATSAPP].extra["unauthorized_dm_behavior"] == "pair"
+
 
 class TestLoadGatewayConfig:
     def test_bridges_quick_commands_from_config_yaml(self, tmp_path, monkeypatch):
@@ -158,3 +174,21 @@ class TestLoadGatewayConfig:
         config = load_gateway_config()
 
         assert config.quick_commands == {}
+
+    def test_bridges_unauthorized_dm_behavior_from_config_yaml(self, tmp_path, monkeypatch):
+        hermes_home = tmp_path / ".hermes"
+        hermes_home.mkdir()
+        config_path = hermes_home / "config.yaml"
+        config_path.write_text(
+            "unauthorized_dm_behavior: ignore\n"
+            "whatsapp:\n"
+            "  unauthorized_dm_behavior: pair\n",
+            encoding="utf-8",
+        )
+
+        monkeypatch.setenv("HERMES_HOME", str(hermes_home))
+
+        config = load_gateway_config()
+
+        assert config.unauthorized_dm_behavior == "ignore"
+        assert config.platforms[Platform.WHATSAPP].extra["unauthorized_dm_behavior"] == "pair"

tests/gateway/test_unauthorized_dm_behavior.py

@@ -0,0 +1,137 @@
+from types import SimpleNamespace
+from unittest.mock import AsyncMock, MagicMock
+
+import pytest
+
+from gateway.config import GatewayConfig, Platform, PlatformConfig
+from gateway.platforms.base import MessageEvent
+from gateway.session import SessionSource
+
+
+def _clear_auth_env(monkeypatch) -> None:
+    for key in (
+        "TELEGRAM_ALLOWED_USERS",
+        "DISCORD_ALLOWED_USERS",
+        "WHATSAPP_ALLOWED_USERS",
+        "SLACK_ALLOWED_USERS",
+        "SIGNAL_ALLOWED_USERS",
+        "EMAIL_ALLOWED_USERS",
+        "SMS_ALLOWED_USERS",
+        "MATTERMOST_ALLOWED_USERS",
+        "MATRIX_ALLOWED_USERS",
+        "DINGTALK_ALLOWED_USERS",
+        "GATEWAY_ALLOWED_USERS",
+        "TELEGRAM_ALLOW_ALL_USERS",
+        "DISCORD_ALLOW_ALL_USERS",
+        "WHATSAPP_ALLOW_ALL_USERS",
+        "SLACK_ALLOW_ALL_USERS",
+        "SIGNAL_ALLOW_ALL_USERS",
+        "EMAIL_ALLOW_ALL_USERS",
+        "SMS_ALLOW_ALL_USERS",
+        "MATTERMOST_ALLOW_ALL_USERS",
+        "MATRIX_ALLOW_ALL_USERS",
+        "DINGTALK_ALLOW_ALL_USERS",
+        "GATEWAY_ALLOW_ALL_USERS",
+    ):
+        monkeypatch.delenv(key, raising=False)
+
+
+def _make_event(platform: Platform, user_id: str, chat_id: str) -> MessageEvent:
+    return MessageEvent(
+        text="hello",
+        message_id="m1",
+        source=SessionSource(
+            platform=platform,
+            user_id=user_id,
+            chat_id=chat_id,
+            user_name="tester",
+            chat_type="dm",
+        ),
+    )
+
+
+def _make_runner(platform: Platform, config: GatewayConfig):
+    from gateway.run import GatewayRunner
+
+    runner = object.__new__(GatewayRunner)
+    runner.config = config
+    adapter = SimpleNamespace(send=AsyncMock())
+    runner.adapters = {platform: adapter}
+    runner.pairing_store = MagicMock()
+    runner.pairing_store.is_approved.return_value = False
+    return runner, adapter
+
+
+@pytest.mark.asyncio
+async def test_unauthorized_dm_pairs_by_default(monkeypatch):
+    _clear_auth_env(monkeypatch)
+    config = GatewayConfig(
+        platforms={Platform.WHATSAPP: PlatformConfig(enabled=True)},
+    )
+    runner, adapter = _make_runner(Platform.WHATSAPP, config)
+    runner.pairing_store.generate_code.return_value = "ABC12DEF"
+
+    result = await runner._handle_message(
+        _make_event(
+            Platform.WHATSAPP,
+            "15551234567@s.whatsapp.net",
+            "15551234567@s.whatsapp.net",
+        )
+    )
+
+    assert result is None
+    runner.pairing_store.generate_code.assert_called_once_with(
+        "whatsapp",
+        "15551234567@s.whatsapp.net",
+        "tester",
+    )
+    adapter.send.assert_awaited_once()
+    assert "ABC12DEF" in adapter.send.await_args.args[1]
+
+
+@pytest.mark.asyncio
+async def test_unauthorized_whatsapp_dm_can_be_ignored(monkeypatch):
+    _clear_auth_env(monkeypatch)
+    config = GatewayConfig(
+        platforms={
+            Platform.WHATSAPP: PlatformConfig(
+                enabled=True,
+                extra={"unauthorized_dm_behavior": "ignore"},
+            ),
+        },
+    )
+    runner, adapter = _make_runner(Platform.WHATSAPP, config)
+
+    result = await runner._handle_message(
+        _make_event(
+            Platform.WHATSAPP,
+            "15551234567@s.whatsapp.net",
+            "15551234567@s.whatsapp.net",
+        )
+    )
+
+    assert result is None
+    runner.pairing_store.generate_code.assert_not_called()
+    adapter.send.assert_not_awaited()
+
+
+@pytest.mark.asyncio
+async def test_global_ignore_suppresses_pairing_reply(monkeypatch):
+    _clear_auth_env(monkeypatch)
+    config = GatewayConfig(
+        unauthorized_dm_behavior="ignore",
+        platforms={Platform.TELEGRAM: PlatformConfig(enabled=True, token="***")},
+    )
+    runner, adapter = _make_runner(Platform.TELEGRAM, config)
+
+    result = await runner._handle_message(
+        _make_event(
+            Platform.TELEGRAM,
+            "12345",
+            "12345",
+        )
+    )
+
+    assert result is None
+    runner.pairing_store.generate_code.assert_not_called()
+    adapter.send.assert_not_awaited()