Update _strip_str to remove null characters

[wenyiz2021]

Modify _strip_str method to remove null characters.
e.g.sudo redis-cli -n 6 HGET 'TRANSCEIVER_INFO|Ethernet0' manufacturer | xxd | head -5;

The redis value stored is:
41 00 00 00 00 00 4e 65 74 77 6f 72 6b 73
A \0 \0 \0 \0 \0 N e t w o r k s

this is causing test_snmp_phy_entity to fail because of failing to parse the \0 above.

>           assert transceiver_snmp_fact['entPhysMfgName'] == transceiver_info['manufacturer'], (
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                'Transceiver manufacturer name mismatch. Expected "entPhysMfgName" to be {}, '
                'but got {}. '
            ).format(
                transceiver_info['manufacturer'],
                transceiver_snmp_fact['entPhysMfgName']
            )
E           AssertionError: Transceiver manufacturer name mismatch. Expected "entPhysMfgName" to be ANetworks, but got A.

the failure was only seen on one of the DUT

which had

docker exec snmp redis-cli -n 6 HGET 'TRANSCEIVER_INFO|Ethernet0' manufacturer | xxd | head -5
00000000: 4100 0000 0000 4e65 7477 6f72 6b73 0a    A.....Networks.

so failing to strip the \0 is causing ssnmp agent returns just A

on another DUT it is fine because of not having \0:

admin@str5-7280r4-ut2-3:~$ docker exec snmp redis-cli -n 6 HGET 'TRANSCEIVER_INFO|Ethernet0' manufacturer | xxd | head -5
00000000: 4172 6973 7461 204e 6574 776f 726b 730a  Arista Networks.

Description

Motivation and Context

How Has This Been Tested?

applied the fix on dut directly and restarted xcvrd:
in /usr/local/lib/python3.11/dist-packages/sonic_platform_base/sonic_xcvr/api/public/cmis.py

Before: 41 00 00 00 00 00 4e 65 74 77 6f 72 6b 73 → A\x00\x00\x00\x00\x00Networks
After: 41 4e 65 74 77 6f 72 6b 73 → ANetworks

Additional Information (Optional)

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[Copilot]

Pull request overview

This PR updates the CMIS transceiver API string sanitization so that EEPROM-decoded strings containing embedded NUL (\x00) characters are cleaned up before being returned, addressing cases where downstream consumers (e.g., SNMP-related tests) only see a truncated prefix.

Changes:

• Extend CmisApi._strip_str() to remove embedded \x00 characters before trimming trailing whitespace.

[mssonicbld]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[mihirpat1]

@wenyiz2021 Isn't this a module issue wherein the vendor has not padded spaces and has instead used null character?

[wenyiz2021]

@wenyiz2021 Isn't this a module issue wherein the vendor has not padded spaces and has instead used null character?

thanks @mihirpat1 for bringing up, not sure, I've also asked vendor to check thihs PR but they havn't replied. looks like just that string issue on dut.

[wenyiz2021]

looks like wrong cable transceiver info

[arista-nwolfe]

We believe this is a 1-off issue with a XCVR, we shouldn't try to handle this in S/W