Assertion: 10320:BSONElement: bad type

[Pawel Veselov]

Mongo: 2.2.0.

I was seeing exceptions, like the one below. The actual 'bad type' varied - I've seen 49, and 51. That's probably not important.

What I was doing : calling a map/reduce job using Java drivers. To create 'compound' keys for some of the reduced data, I was passing over a character code that would separate the elements of a compound key:

                char separator = '\u0000';

                scope.put("G_SEPARATOR", (int)separator);

The scope map is passed as scope for M/R job. In JS:

    var sep = String.fromCharCode(G_SEPARATOR);

Then certain keys are built with:

            key = this.field1 + sep + this.field2;

The special key code is used to prevent clashing character between the separators and the values of the keys.

I don't really know at which point this all breaks. I assume that it breaks when trying to retrieve "G_SEPARATOR" from the global scope, otherwise I don't see how this exception will happen where it happens.

I don know that once I changed the character code to '\0001', things got back to normal. I would expect that there may be some problems with handling strings that have '\0' in them, but this value is passed as an integer, so I don't know.

Anyway, may somebody should take a look into this, and see what may be going on. Let me know if you'd like to me create SSCCE.

Mon Oct 22 11:43:23 [conn2] Assertion: 10320:BSONElement: bad type 49

0x667666 0x621488 0x590b6d 0x8e02a3 0x654847 0x655958 0xa37294 0x83c377 0x848548 0x848c39 0xa57c05 0x8ec7be 0x9d3eb1 0x9ca3be 0x9cb49f 0x9cf894 0x9cfc89 0x9d645d 0xa5d8bc 0xa5f749 

 /usr/local/bin/mongod(_ZN5mongo15printStackTraceERSo+0x26) [0x667666]

 /usr/local/bin/mongod(_ZN5mongo11msgassertedEiPKc+0x98) [0x621488]

 /usr/local/bin/mongod(_ZNK5mongo11BSONElement4sizeEv+0x12d) [0x590b6d]

 /usr/local/bin/mongod(_ZN5mongo16resolveBSONFieldEP9JSContextP8JSObjectljPS3_+0x133) [0x8e02a3]

 /usr/local/bin/mongod(js_LookupPropertyWithFlags+0x1e7) [0x654847]

 /usr/local/bin/mongod(js_GetProperty+0x78) [0x655958]

 /usr/local/bin/mongod(js_ValueToIterator+0xb4) [0xa37294]

 /usr/local/bin/mongod(js_Interpret+0x20c7) [0x83c377]

 /usr/local/bin/mongod(js_Invoke+0xab8) [0x848548]

 /usr/local/bin/mongod(js_InternalInvoke+0x119) [0x848c39]

 /usr/local/bin/mongod(JS_CallFunction+0x25) [0xa57c05]

 /usr/local/bin/mongod(_ZN5mongo7SMScope6invokeEP10JSFunctionPKNS_7BSONObjES5_ibbb+0x3ce) [0x8ec7be]

 /usr/local/bin/mongod(_ZN5mongo5Scope10invokeSafeEyPKNS_7BSONObjES3_ibbb+0x41) [0x9d3eb1]

 /usr/local/bin/mongod(_ZN5mongo2mr9JSReducer7_reduceERKSt6vectorINS_7BSONObjESaIS3_EERS3_Ri+0x7de) [0x9ca3be]

 /usr/local/bin/mongod(_ZN5mongo2mr9JSReducer6reduceERKSt6vectorINS_7BSONObjESaIS3_EE+0x6f) [0x9cb49f]

 /usr/local/bin/mongod(_ZN5mongo2mr5State14reduceInMemoryEv+0x104) [0x9cf894]

 /usr/local/bin/mongod(_ZN5mongo2mr5State9checkSizeEv+0x59) [0x9cfc89]

 /usr/local/bin/mongod(_ZN5mongo2mr16MapReduceCommand3runERKSsRNS_7BSONObjEiRSsRNS_14BSONObjBuilderEb+0xb5d) [0x9d645d]

 /usr/local/bin/mongod(_ZN5mongo12_execCommandEPNS_7CommandERKSsRNS_7BSONObjEiRNS_14BSONObjBuilderEb+0x4c) [0xa5d8bc]

 /usr/local/bin/mongod(_ZN5mongo11execCommandEPNS_7CommandERNS_6ClientEiPKcRNS_7BSONObjERNS_14BSONObjBuilderEb+0x739) [0xa5f749]

Mon Oct 22 11:43:23 [conn2] JS Error: Error: BSONElement: bad type 49 nofile_b:84

Mon Oct 22 11:43:23 [conn2] warning: ClientCursor::YieldLock not closed properly

Mon Oct 22 11:43:23 [conn2] mr failed, removing collection :: caused by :: 9004 invoke failed: JS Error: Error: BSONElement: bad type 49 nofile_b:84

[Thomas Rueckstiess]

Yes, this is a known issue: You cannot insert null characters as part of a key or in a regular expression. Doing so will create corrupt BSON documents that usually result in these "bad type" assertions.

The bug ticket is https://jira.mongodb.org/browse/SERVER-7005.

The problem here is, that the name of a key is stored as a simple cstring (see also the BSON specifications) and any contained null character cannot be distinguished from the terminal null character for the string. 

Some of the drivers prohibit you from inserting null characters, but Java does not (yet). 

Please use a different separation character as a work-around for your problem.

Regards,

Thomas