Fix slack_bolt engine UnboundLocalError on workflow/bot messages (#68105)

changelog/68105.fixed.md

@@ -0,0 +1 @@
+Fixed ``slack_bolt`` engine crashing with ``UnboundLocalError`` when a Slack workflow or other bot posts a message to a monitored channel. Bot messages (``subtype: bot_message``) carry ``bot_id`` and ``username`` instead of a ``user`` field, and these are now used as fallbacks so the engine continues running.

salt/engines/slack_bolt_engine.py

@@ -584,6 +584,8 @@ def generate_triggered_messages(
 
         def just_data(m_data):
             """Always try to return the user and channel anyway"""
+            user_id = None
+            user_name = None
             if "user" not in m_data:
                 if "message" in m_data and "user" in m_data["message"]:
                     log.debug(
@@ -595,17 +597,30 @@ def just_data(m_data):
                 elif "comment" in m_data and "user" in m_data["comment"]:
                     log.debug("Comment was added, so we look for user in the comment.")
                     user_id = m_data["comment"]["user"]
+                elif m_data.get("subtype") == "bot_message":
+                    # Workflows and other bot-posted messages do not carry a
+                    # ``user`` field. Fall back to the bot identity so the
+                    # message can still be processed instead of crashing the
+                    # engine with UnboundLocalError. See issue #68105.
+                    log.debug(
+                        "Message was posted by a bot/workflow, "
+                        "so we use the bot id and username."
+                    )
+                    user_id = m_data.get("bot_id")
+                    user_name = m_data.get("username")
             else:
                 user_id = m_data.get("user")
             channel_id = m_data.get("channel")
             if channel_id.startswith("D"):  # private chate with bot user
                 channel_name = "private chat"
             else:
                 channel_name = all_slack_channels.get(channel_id)
+            if user_name is None:
+                user_name = all_slack_users.get(user_id)
             data = {
                 "message_data": m_data,
                 "user_id": user_id,
-                "user_name": all_slack_users.get(user_id),
+                "user_name": user_name,
                 "channel_name": channel_name,
             }
             if not data["user_name"]:

tests/pytests/unit/engines/test_slack_bolt_engine.py

@@ -2,6 +2,8 @@
 unit tests for the slack engine
 """
 
+from collections import deque
+
 import pytest
 
 import salt.engines.slack_bolt_engine as slack_bolt_engine
@@ -416,6 +418,80 @@ def test_run_commands_from_slack_async(slack_client):
         mock_event_send.asser_has_calls(event_send_calls)
 
 
+def test_generate_triggered_messages_bot_message_68105(slack_client):
+    """
+    Regression test for issue #68105.
+
+    A Slack workflow that posts to a channel produces a message with
+    ``subtype: 'bot_message'`` and no ``user`` field (it carries ``bot_id``
+    and ``username`` instead). Previously this raised
+    ``UnboundLocalError: local variable 'user_id' referenced before assignment``
+    inside ``just_data`` and crashed the engine. The engine must now handle
+    these bot messages gracefully.
+    """
+
+    # A workflow-posted message: ``subtype: bot_message`` with no ``user``
+    # field. The text does not start with the trigger string so the engine
+    # should simply yield it back without dispatching a command.
+    bot_msg = {
+        "subtype": "bot_message",
+        "text": "hello from a workflow",
+        "username": "Salt Run",
+        "type": "message",
+        "ts": "1750761076.971029",
+        "bot_id": "B092CEC63HV",
+        "app_id": "A092TF7N4R2",
+        "channel": "C02QY11UQ",
+        "event_ts": "1750761076.971029",
+        "channel_type": "group",
+    }
+
+    slack_client.msg_queue = deque([bot_msg])
+
+    patch_run_until = patch.object(
+        slack_client, "_run_until", MagicMock(side_effect=[True, False])
+    )
+    patch_get_users = patch.object(
+        slack_client,
+        "get_slack_users",
+        MagicMock(return_value={"U02QY11UJ": "garethgreenaway"}),
+    )
+    patch_get_channels = patch.object(
+        slack_client,
+        "get_slack_channels",
+        MagicMock(return_value={"C02QY11UQ": "general"}),
+    )
+    patch_get_config_groups = patch.object(
+        slack_client,
+        "get_config_groups",
+        MagicMock(return_value={}),
+    )
+
+    with patch_run_until, patch_get_users, patch_get_channels, patch_get_config_groups:
+        # Consume the generator. The bug raised UnboundLocalError inside
+        # just_data, propagating out of the generator on the first ``next``.
+        results = list(
+            slack_client.generate_triggered_messages(
+                token="xoxb-test",
+                trigger_string="!",
+                groups={},
+                groups_pillar_name="",
+            )
+        )
+
+    # The generator must complete without raising. The bot message is
+    # yielded back as ``data`` (non-trigger path), then the final
+    # ``done`` sentinel.
+    assert any(item.get("done") for item in results)
+    yielded = [item for item in results if not item.get("done")]
+    assert len(yielded) == 1
+    # The bot identity is carried through in place of ``user_id`` /
+    # ``user_name`` so downstream code has something to log.
+    assert yielded[0]["user_id"] == "B092CEC63HV"
+    assert yielded[0]["user_name"] == "Salt Run"
+    assert yielded[0]["message_data"] is bot_msg
+
+
 def test_run_command_async(slack_client):
     """
     Test slack engine: test_run_command_async