Recognize PENDING -> UNKNOWN as state change

... to get notified about that state change.

refs #7807

lib/icinga/checkable-check.cpp

@@ -222,7 +222,7 @@ void Checkable::ProcessCheckResult(const CheckResult::Ptr& cr, const MessageOrig
 		}
 
 		/* SOFT state change, increase attempt counter. */
-		if (old_stateType == StateTypeSoft && !IsStateOK(old_state)) {
+		if (old_stateType == StateTypeSoft && old_cr && !IsStateOK(old_state)) {
 			SetStateType(StateTypeSoft);
 			attempt = old_attempt + 1;
 		}
@@ -266,11 +266,15 @@ void Checkable::ProcessCheckResult(const CheckResult::Ptr& cr, const MessageOrig
 
 	bool stateChange;
 
-	/* Exception on state change calculation for hosts. */
-	if (checkableType == CheckableService)
-		stateChange = (old_state != new_state);
-	else
-		stateChange = (Host::CalculateState(old_state) != Host::CalculateState(new_state));
+	if (old_cr) {
+		/* Exception on state change calculation for hosts. */
+		if (checkableType == CheckableService)
+			stateChange = (old_state != new_state);
+		else
+			stateChange = (Host::CalculateState(old_state) != Host::CalculateState(new_state));
+	} else {
+		stateChange = true;
+	}
 
 	/* Store the current last state change for the next iteration. */
 	SetPreviousStateChange(GetLastStateChange());
@@ -304,9 +308,9 @@ void Checkable::ProcessCheckResult(const CheckResult::Ptr& cr, const MessageOrig
 	if (GetAcknowledgement() == AcknowledgementNone)
 		remove_acknowledgement_comments = true;
 
-	bool hardChange = (GetStateType() == StateTypeHard && old_stateType == StateTypeSoft);
+	bool hardChange = (GetStateType() == StateTypeHard && old_stateType == StateTypeSoft && old_cr);
 
-	if (stateChange && old_stateType == StateTypeHard && GetStateType() == StateTypeHard)
+	if (stateChange && (old_stateType == StateTypeHard || !old_cr) && GetStateType() == StateTypeHard)
 		hardChange = true;
 
 	bool is_volatile = GetVolatile();