Thanks to the very detailed bug report, this has now been fixed. Sequences used inside OBJECT TYPE:s have their elements checked against the MIB, and any missing element is added to the MIB with reasonable default values. A loader warning is also issued when creating new symbols like this.

This validation check has found errors in RFC 1243 and RFC 1253 that have also been corrected.

This fix will be released in version 2.2.

Sequence elements with a defined type but no defined
left-hand symbol should be assigned a default symbol name based on the enclosing Sequence's OID.

Example:

--Defined symbols:
--
-- nncAlmDateAndTime
-- nncAlmPriority
-- nncAlmText

--Undefined Symbols:
--
-- nncAlmSubcode
-- nncAlmParms

.
.
.

   nncAlmInfo        OBJECT-TYPE
                 SYNTAX  SEQUENCE OF NncAlmInfo
                 MAX-ACCESS  not-accessible
                 STATUS  current
                 DESCRIPTION
                   "Alarm information shared by all alarm trap types."
                 ::= { nncExtNotifObjects 2 }

   NncAlmInfo        ::= SEQUENCE {
                     nncAlmDateAndTime         TimeTicks,
                     nncAlmPriority       AlmPriorityType,
                     nncAlmText                StringType,
                     nncAlmSubcode             StringType,
                     nncAlmParms      ParameterStringType
                  }

-- Discussion

The undefined symbols (nncAlmSubcode and nncAlmParms) in the sequence are shown in Java via:

mibvalsym.getValue().toString()

where mibvalsym is the nncAlmInfo ObjectIdentifierValue. The toString() resolves to:

OBJECT-TYPE (
  Syntax: SEQUENCE OF SEQUENCE [nncAlmDateAndTime INTEGER (0..4294967295), nncAl
mPriority TEXTUAL-CONVENTION (
  Status: current
  Description: Different alarm priorities.
  Syntax: INTEGER (1 | 2 | 3 | 4)
), nncAlmText TEXTUAL-CONVENTION (
  Status: current
  Description: Types used to forward various text fields.
  Syntax: OCTET STRING (SIZE (0..30))
), nncAlmSubcode TEXTUAL-CONVENTION (
  Status: current
  Description: Types used to forward various text fields.
  Syntax: OCTET STRING (SIZE (0..30))
), nncAlmParms TEXTUAL-CONVENTION (
  Status: current
  Description: Types used to forward various text fields.
  Syntax: OCTET STRING (SIZE (0..40))
)[
  Access: not-accessible
  Status: current
  Description: Alaram information shared by all alarm trap types.


The child count in the sequence's ObjectIdentifierValue is three instead of five, which means that the unknown input element's objects where not created.


In contrast, using snmptrap daemon (from NET-SNMP, formerly UCD-SNMP) under Linux, the trapdaemon's ASN.1 analyser fills in missing nams with the parent sequence's OID plus the missing symbol's position:

.
.
.1.3.6.1.4.1.123.3.44.1.2.1 --> nncAlmDateAndTime == 122:21:52:09.33
.1.3.6.1.4.1.123.3.44.1.2.2 --> nncAlmPriority == 3
.1.3.6.1.4.1.123.3.44.1.2.3 --> nncAlmText == "PVC Active S1"
.1.3.6.1.4.1.123.3.44.1.2.4 --> nncAlmInfo.4 == "S1 1,39 "
.1.3.6.1.4.1.123.3.44.1.2.5 --> nncAlmInfo.5 == "1,39 "

-----------

Reason for bringing this up: external customers can load arbitrary MIBs and the java code is expected to see and manipulate the "missing" entries.