fix(slack): split csv mention pattern fallback

plugins/platforms/slack/adapter.py

@@ -3838,9 +3838,7 @@ class SlackAdapter(BasePlatformAdapter):
                     import json as _json
                     patterns = _json.loads(raw)
                 except Exception:
-                    patterns = [p.strip() for p in raw.splitlines() if p.strip()] or [
-                        p.strip() for p in raw.split(",") if p.strip()
-                    ]
+                    patterns = [p.strip() for p in raw.replace("\n", ",").split(",") if p.strip()]
 
         if isinstance(patterns, str):
             patterns = [patterns]

tests/gateway/test_slack_mention.py

@@ -735,6 +735,16 @@ def test_mention_patterns_env_var_fallback(monkeypatch):
     assert adapter._slack_message_matches_mention_patterns("hey hermes") is True
 
 
+def test_mention_patterns_env_var_csv_fallback_splits_patterns(monkeypatch):
+    monkeypatch.setenv("SLACK_MENTION_PATTERNS", "hey hermes,hermes,")
+    adapter = _make_adapter()  # no config value -> falls back to env
+
+    patterns = adapter._slack_mention_patterns()
+
+    assert [pattern.pattern for pattern in patterns] == ["hey hermes", "hermes"]
+    assert adapter._slack_message_matches_mention_patterns("hey hermes") is True
+
+
 def test_mention_patterns_trigger_in_channel_without_literal_mention():
     """A wake word triggers the bot in a channel even with require_mention on."""
     adapter = _make_adapter(require_mention=True, mention_patterns=["hey hermes"])