[caclmgrd] Skip empty ACL tables

[nazariig]

This PR propagates a fix for timing issue caused by caclmgrd processing of ACL tables during Config DB record removal operation.

Evidence from code

• What caclmgrd does

self._tables_db_info = config_db_connector.get_table(self.ACL_TABLE)
...
if table_data["type"] != self.ACL_TABLE_TYPE_CTRLPLANE:

• ConfigDBConnector.get_table() is implemented as

const auto& keys = client.keys(pattern);
for (auto& key: keys)
{
    auto const& entry = client.hgetall<map<string, string>>(key);

This is a two-step read:

1. list keys (KEYS ACL_TABLE|*)
2. per key HGETALL

If a key is deleted/changed between step 1 and step 2, hgetall can return {}.
Then table_data exists as an empty map in _tables_db_info, and table_data["type"] throws KeyError.

So missing type does NOT require field-only deletion; plain key deletion racing with get_table() is enough.

Also field-only deletion is possible in the stack:

client.hmset(_hash, data.begin(), data.end());
...
if (!found)
{
    client.hdel(_hash, k);
}

set_entry() can remove extra fields with HDEL while keeping the record key alive.

Evidence from pytest

The log shows rapid table deletes:

sudo config acl remove table DATA_INGRESS_L3TEST
...
sudo config acl remove table DATA_EGRESS_L3V6TEST

That high churn exactly matches a race window for the non-atomic get_table() read in caclmgrd.

So missing type can happen via:

• field-level HDEL updates
• key-level delete race during KEYS + HGETALL snapshot collection

SYSLOG:

syslog:2026 Mar 27 03:57:03.486679 sonic INFO start-LogAnalyzer-test_acl_config.2026-03-27-00:57:02
syslog:2026 Mar 27 03:57:08.378308 sonic ERR caclmgrd: Exception occured at Thread-2 (check_and_update_control_plane_acls) thread for namespace '' due to KeyErro
r('type')
syslog:2026 Mar 27 03:57:08.874919 sonic ERR caclmgrd: Main thread detected exception in child thread for namespace '': KeyError('type')
syslog:2026 Mar 27 03:57:08.875092 sonic ERR caclmgrd: Full traceback from child thread:
syslog:2026 Mar 27 03:57:08.875239 sonic ERR caclmgrd: Traceback (most recent call last):
syslog:2026 Mar 27 03:57:08.875386 sonic ERR caclmgrd:   File "/usr/local/bin/caclmgrd", line 970, in check_and_update_control_plane_acls
syslog:2026 Mar 27 03:57:08.875532 sonic ERR caclmgrd:     self.update_control_plane_acls(namespace, new_config_db_connector)
syslog:2026 Mar 27 03:57:08.875668 sonic ERR caclmgrd:     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
syslog:2026 Mar 27 03:57:08.875845 sonic ERR caclmgrd:   File "/usr/local/bin/caclmgrd", line 907, in update_control_plane_acls
syslog:2026 Mar 27 03:57:08.875984 sonic ERR caclmgrd:     iptables_cmds, service_to_source_ip_map  = self.get_acl_rules_and_translate_to_iptables_commands(names
pace, config_db_connector)
syslog:2026 Mar 27 03:57:08.876104 sonic ERR caclmgrd:                                                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^
^^^^^^^^^^^^^^^^^^^^^^^^^^
syslog:2026 Mar 27 03:57:08.876176 sonic ERR caclmgrd:   File "/usr/local/bin/caclmgrd", line 740, in get_acl_rules_and_translate_to_iptables_commands
syslog:2026 Mar 27 03:57:08.876239 sonic ERR caclmgrd:     if table_data["type"] != self.ACL_TABLE_TYPE_CTRLPLANE:
syslog:2026 Mar 27 03:57:08.876302 sonic ERR caclmgrd:        ~~~~~~~~~~^^^^^^^^
syslog:2026 Mar 27 03:57:08.876362 sonic ERR caclmgrd: KeyError: 'type'
syslog:2026 Mar 27 03:57:08.876420 sonic ERR caclmgrd: Detect exception in Child thread, generating SIGKILL for main thread
syslog:2026 Mar 27 03:57:21.252620 sonic INFO end-LogAnalyzer-test_acl_config.2026-03-27-00:57:02
syslog:2026 Mar 27 03:57:22.329663 sonic INFO python3.13[156612]: ansible-extract_log Invoked with directory=/var/log file_prefix=syslog start_string=start-LogAnalyzer-test_acl_config.2026-03-27-00:57:02 target_filename=/tmp/syslog
syslog:2026 Mar 27 03:57:22.329874 sonic DEBUG extract_log for start string LogAnalyzer-test_acl_config.2026-03-27-00:57:02

A picture of a cute animal (not mandatory but encouraged)

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   //////   ' \/ `   ---
  //// / // :    : ---
 // /   /  /`    '--
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             ''``

[mssonicbld]

/azp run

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Azure Pipelines successfully started running 1 pipeline(s).

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[nazariig]

@vmittal-msft this is a simple fix. Can you please help to merge?

[mssonicbld]

Cherry-pick PR to 202511: #381