runger, I'm interested to hear that you say you would expect a page with an actionFunction to call  the controller constructor twice. Does this mean that this really is expected behaviour? Anyone else of the same opinion?

Below is some example code:

public with sharing class example_widget {

	public string searchText { get; set; }
	
	public example_widget() {
		System.debug('** Constructor: ');
	}
	
	
	public PageReference goSearch() {
		PageReference resultPageRef = new PageReference('/apex/example_search');
		resultPageRef.getParameters().put('searchText', searchText);

		resultPageRef.setRedirect(true);
		return resultPageRef;
	}
	
	public void doSomething() {
		System.debug('** Action method done');
	}

}

<apex:component controller="example_widget" allowDML="true">

	<apex:form >
	<apex:actionFunction action="{!doSomething}" name="doSomething" />
	<div>
	<apex:inputText value="{!searchText}"/>
		<apex:commandButton action="{!goSearch}" value="Go"/>
	</div>
	</apex:form>

</apex:component>

<apex:page >
	<c:example_widget />
</apex:page>

This piece of example code proves the point that when an actionFunction is present in the component, the controller constructor is called twice and when the actionFunction is removed the constructor is only called once. This is not related to when the actionfunction apex method is actually called - this example code doesn't even attempt to call the actionFunction. Just the presence of the actionFunction seems to cause this behaviour.

If this is really expected behaviour, which seems very strange to me, but if it is.... is there any way to prevent constructor code being called twice upon instantiation of the controller? It would seem bizaare not be be able to rely on the constructor being called only once on instantiation.