Fix: Add nullcheck for linkedGoods

[Dorus]

While using YaFC-CE today i ran into an exception because linkedGoods in summer.TryGetValue(linkedGoods, ...) was null. This fixed that.

It's kinda a blind fix since i have no steps to reproduce, YaFC was hanging right after the exception message (i made another issue for that). But judging the code this should work.

[shpaass]

Any idea why linkedGoods was null? It's doesn't happen often because otherwise we would've encountered it earlier, so I am curious.

[Dorus]

I'm unable to say, i was clicking around and adding a lot of recipes, changing fuels, changing links etc. Using both left click, right click, ctr+click. And i have a memory of a frog sometimes so i couldn't reproduce it.

[shpaass]

As we don't know the reason behind the linkedGoods being null, I suggest to add a logger in addition to the current changes. Let it write all relevant info to the file and show a warning similar to the error message when in the debug mode. This way, you or other devs will eventually collect enough info to understand the reason behind the error.

[Dorus]

It seems to be an issue that YaFC is running multiple threads, and sometimes modifications are made to the items it is already iterating over.

(This also returned the previous mentioned freeze in #192)

I just got a similar but different error than last time while trying to reproduce it.

[Dorus]

Random idea: But did we already run multiple threads like this at or before update 0.7.0?

[Dorus]

Another update: I got him:

I added a thread.sleep to make it a little easier to trigger, but then if you are iterating this code before linked goods are added, it gets to this. You need to have an empty group, and add a new item to it, remove it, and add it again, and then at an unlucky time:

->

For a brief moment you'll notice the ingredients are missing. These get added a fraction of a second later (but slowly because of my debug thread.sleep). If unlucky, it crashes before these ingredients are actually added.

This happens especially when you add/remove that first sub-recipe a couple times in a row. It helps that i have a very large recipe tab. Still, without the extra sleep i cannot reproduce it now, but it is how i got it the first time.

[Dorus]

As we don't know the reason behind the linkedGoods being null, I suggest to add a logger in addition to the current changes. Let it write all relevant info to the file and show a warning similar to the error message when in the debug mode. This way, you or other devs will eventually collect enough info to understand the reason behind the error.

Eeeh, stupid question, do we log with Debug.WriteLine or Console.Writeline? I dont think we've ever made work of adding ILogger to the system.

[shpaass]

do we log with Debug.WriteLine or Console.Writeline?

My idea was to log both in the console and the file.
Regarding your question, I'm not sure which option is correct. We need to check what logging approach is present and see if we want to keep or change it.

[Dorus]

Also, i've verified my fix works, do we still need the log line?

I can put it on my list to give the logger a swing, but i got at most an hour tomorrow to hack away at it so idk if i can get anything done in that department.

[shpaass]

I suggest to add at least the logging that you mentioned in your prevoius message, with the comment that this type of logging is not set in stone.

[Dorus]

Done 👍