Description:
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snmp_read_mib() returns a boolean depending on success of the read. Internally, the reab_mib() call returns either NULL or the root of the mib-tree, depending on succes. This problem here is that read_mib ONLY returns NULL when the mib-file is not found and not when there is a parse-error inside the file. In that case it will just return the mib root tree (which is !null) and thus it will return true back to the php user.


As a sidenote (maybe a different bug): snmp_disable_stderrlog() does not work 100% for disabling snmp error logging. Net-snmp wants at least 1 type of log handler active at all times. A simple fix would be to add snmp_enable_calllog(), so it would use the callback handler for logging (and since there are no handlers registered, no logging would occur). It would be nicer though to actually have a callback registered which can return info back to php level (snmp_[clear|get]_log for instance). The code for this functional and can be supplied as a patch against php5.3 and the new OO api in trunk. 

Test script:
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var_dump(snmp_read_mib("cannotfindthisfile")); 
var_dump(snmp_read_mib("incorrectmibfile")); 


Expected result:
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bool(false)
bool(false)

Actual result:
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bool(false)
Warning: snmp_read_mib(): Error while reading MIB file '%s': No such file or directory in %s on line %d
bool(true)