Werk #5460: Waiting without a wait condition immediately returns now

Component Livestatus
Title Waiting without a wait condition immediately returns now
Date Nov 17, 2017
Level Trivial Change
Class Bug Fix
Compatibility Incompatible - Manual interaction might be required
Checkmk versions & editions
1.5.0i1
Not yet released
Checkmk Raw (CRE), Checkmk Enterprise (CEE), Checkmk MSP (CME)
1.5.0i1
Not yet released
Checkmk Raw (CRE), Checkmk Enterprise (CEE), Checkmk MSP (CME)
1.5.0i1
Not yet released
Checkmk Raw (CRE), Checkmk Enterprise (CEE), Checkmk MSP (CME)
1.5.0i1
Not yet released
Checkmk Raw (CRE), Checkmk Enterprise (CEE), Checkmk MSP (CME)
1.5.0i1
Not yet released
Checkmk Raw (CRE), Checkmk Enterprise (CEE), Checkmk MSP (CME)
1.5.0i1
Not yet released
Checkmk Raw (CRE), Checkmk Enterprise (CEE), Checkmk MSP (CME)
1.5.0i1 Checkmk Raw (CRE), Checkmk Enterprise (CEE), Checkmk MSP (CME)
1.4.0p25 Checkmk Raw (CRE), Checkmk Enterprise (CEE), Checkmk MSP (CME)

Note: This change only affects users writing their own tools for the Livestatus interface, and only those tools which rely on an edge case.

Up to now, Livestatus had a special obscure case: Using a WaitTrigger header in a query without a WaitCondition header resulted in waiting for the trigger exactly once. This is a misfeature, because it is effectively useless and doesn't do what one might expect: Due to spurious wakeups (https://en.wikipedia.org/wiki/Spurious_wakeup), waiting might return earlier basically at any time.

To fix this behaviour, the special case has been removed, and a missing WaitCondition always has its expected semantics (always true) now. Note that this is consistent with a missing Filter header, which means "no filtering".

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