[pysnmp-users] UnboundLocalError: local variable 'errorIndication' referenced before assignment

[Patrick O. <pa...@og...>]

Hello,

I ran into a problem after upgrading to pysnmp 4.3.0.

Just running snmpwalk it looks like this:

$ snmpwalk -v2c -c public 172.29.50.5 1.3.6.1.4.1.9.9.46.1.4.2
SNMPv2-SMI::enterprises.9.9.46.1.4.2 = No Such Object available on this
agent at this OID

The problem seems to be when you run a nextCmd against an object which
currently doesn't exist.

The code below works with pysnmp 4.2.5

from pysnmp.entity.rfc3413.oneliner import cmdgen
cmdGen = cmdgen.CommandGenerator()

errorIndication, errorStatus, errorIndex, varBindTable = cmdGen.nextCmd(
    cmdgen.CommunityData('public'),
    cmdgen.UdpTransportTarget(('172.29.50.5', 161)),
    '1.3.6.1.4.1.9.9.46.1.4.2',
    lookupMib=False,
)

if errorIndication:
    print(errorIndication)
else:
    if errorStatus:
        print('%s at %s' % (
            errorStatus.prettyPrint(),
            errorIndex and varBindTable[-1][int(errorIndex)-1] or '?'
            )
        )
    else:
        for varBindTableRow in varBindTable:
            for name, val in varBindTableRow:
                print('%s = %s' % (name.prettyPrint(), val.prettyPrint()))

As the object doesn't exist on the device nothing is printed out. However
running the same code with 4.3.0 gives this error:

Traceback (most recent call last):
  File "<stdin>", line 5, in <module>
  File
"/Users/patrick/.virtualenvs/prod/lib/python2.7/site-packages/pysnmp/entity/rfc3413/oneliner/cmdgen.py",
line 222, in nextCmd
    return errorIndication, errorStatus, errorIndex, varBindTable
UnboundLocalError: local variable 'errorIndication' referenced before
assignment

Is this something which can be solved in an easy way?

Best regards
Patrick