Pixel Crushers Forum

Posted: **Thu Jun 03, 2021 7:47 am**

Hi again, I have created the previous post where I described my problem.

In this post, I want to report the bug.

Steps to reproduce the bug:

Using an empty Unity project with only QuestMachine imported
Locate "Pesky Rabbits" quest
Set the "rabbits" counter value to 1
In Autostart, add a CounterQuestCondition
Set "Required Counter Value" to 1

This bug occurs because the QuestCondition is true at the moment the Quest is initialized by the QuestGiver, thus it sets the condition to true. This causes a StackOverflowException because the code goes into an infinite loop.

Code blocks related to the issue:

Code: Select all

[b]Quest.cs[/b]
public void BecomeUnofferable()
{
	try
        {
        	if (GetState() != QuestState.Disabled) SetState(QuestState.Disabled);
                	SetQuestIndicatorState(questGiverID, QuestIndicatorState.None);
        }
        catch (Exception e) // Don't let exceptions in user-added events break our code.
        {
                if (Debug.isDebugBuild) Debug.LogException(e);
        }
}

Code: Select all

[b]Quest.cs[/b]
public void SetState(QuestState newState, bool informListeners = true)
{
	if (QuestMachine.debug) Debug.Log("Quest Machine: " + GetEditorName() + ".SetState(" + newState + ", informListeners=" + informListeners + ")", this);

	m_state = newState;

	SetStartChecking(newState == QuestState.WaitingToStart);
	SetCounterListeners(newState == QuestState.Active || (newState == QuestState.WaitingToStart && (hasAutostartConditions || hasOfferConditions)));
	....
}

Posted: **Thu Jun 03, 2021 2:27 pm**

Thanks for reporting this bug. I'll investigate and provide a patch here later today.

Posted: **Thu Jun 03, 2021 5:02 pm**

Hi,

Here's the patch:

QM_AutostartPatch_2021-06-03.unitypackage

Posted: **Fri Jun 04, 2021 4:37 am**

Great! Thanks a lot.

Posted: **Fri Jun 04, 2021 5:41 am**

Hi Tony!

I think there are more issues in regards to the Autostart.

I will try to explain it below.

So let us consider the following scenario:

We have a Quest that has an Autostart QuestCondition
The Quest is added to the player's QuestJournal
This condition is true at the moment the quest is started up by the QuestJournal
The Quest consists of 3 nodes, Start, Condition, and Success
The Condition QuetNode has some TestQuestCondition
This TestQuestCondition prints a "Subscribe" debug log when the StartChecking() is called
This TestQuestCondition prints an "Unsubscribe" debug log when the StopChecking() is called

The problem that occurs is the following:

We play the game
The Quest checks for the Autostart condition
The condition is true, thus the Quest state changes to Active
The Console prints out both "Subscribe" and "Unsubscribe" logs

The reason why I think this happens is the following:

It all has to do with the SetState() function in the Quest.cs
When the game starts, this method is called with newState = WaitingToStart
It then calls SetStartChecking(true), since newState == WaitingToStart
Consequently, it goes through the Autostart conditions
We only have 1 Autostart condition which is true
As a result, SetState() is called again with newState = Active. This happens before the previous SetState() method has finished!!!
This then calls StartChecking() on the only QuestCondition of our only CondiutionQuestNode, thus printы "Subscribe" to the console
Then, when the second SetState() method finishes execution, it goes back to the first SetState() execution!!!
Which then does the following check: if (newState == Active) StopNodeListeners();
Since this is the first iteration of the SetState() method, newState equals to WaitingToStart, therefore StopNodeListeners() is called.
Which consequently gets to our only Condition and prints out "Unsubscribe"

Code: Select all

public void SetState(QuestState newState, bool informListeners = true)
        {
            if (QuestMachine.debug) Debug.Log("Quest Machine: " + GetEditorName() + ".SetState(" + newState + ", informListeners=" + informListeners + ")", this);


            Debug.Log($"NewState: {newState}, MyState: {m_state}");

            m_state = newState;

            SetStartChecking(newState == QuestState.WaitingToStart);
            SetCounterListeners(newState == QuestState.Active || (newState == QuestState.WaitingToStart && (hasAutostartConditions || hasOfferConditions)));
            if (newState != QuestState.Active) StopNodeListeners();
	...
        }

I hope this explanation provides enough information, please let me know if you need any follow-up information from me.

Looking forward to your response.

Posted: **Fri Jun 04, 2021 10:46 am**

Thank you for the breakdown. As you described, the SetState() method wasn't considering that the state may change after calling SetStartChecking(). This patch addresses that:

QM_QuestStatePatch_2021-06-04.unitypackage

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