Inconsistent startup crash due to custom multiblock registry, sometimes crashes, sometimes launches

[woeful plinth]

I'm not sure what is going on here, but when i launch the game the first time of the day, i get a crash due to a custom multiblock registry, being:

Suppressed: java.lang.IllegalStateException: missing pattern while creating multiblock hydrovolcanism_generator

But if i do absolutely nothing about it and relaunch the pack, it opens fine after the first time. I've never had this behavior with any other custom multis and can't grasp why it crashes once, then runs fine after that. I have 20+ other custom multis but this is the only generator type. The first time it happened the other day I thought it was a weird fluke, but it still happens. It's the only thing I've used so far that has both .generator and .regressWhenWaiting being used, not sure if tied to one of those somehow. Also possibly the empty .recipeModifiers but I figured if empty it would be fine. The pack is Sky Greg on an unreleased version.

I uploaded the multiblock registry as an image as I hit character limit.

1.20.1, Forge
GT 7.4.1

[woeful plinth]

Seemingly it's randomly crashing on startup because of this, I just had 2 successful game reboots followed by 2 crashes on startup, followed by a successful startup, with the same "missing pattern" log. All with absolutely nothing changing in the entire related file. I guess prior to today I just didn't have as many game reboots.

[woeful plinth]

Inconsistent startup crash due to custom multiblock registry, sometimes crashes, sometimes launches

[wet pendant]

Ask phoenixvine, he should have a solution, search through his messages and modify the code from his example to fit your multiblock

[woeful plinth]

ty will do

@trail horizon Sorry for the @ but you were recommended and I did look through your posts first but I only saw one custom generator post with minor differences and nothing jumped out at me from the example. Any chance you can see an issue with this/had an issue like this? Specifically having random startup crashes that do not happen every time? I've never seen startup crashes with behavior like that before (sometimes crashes with log line above, sometimes starts up fine), and the multi does form and run when it does start. I could post the text of the structure registry in a file or in two halves, I just hit a 2k character limit is all.

[trail horizon]

Ill look on my lunch break. Can you post the latest log and crash report?

[woeful plinth]

Will do, thank you

I do see some things yelling about other things but this one line is present which i often hit with multiblock registry errors.
Suppressed: java.lang.IllegalStateException: missing pattern while creating multiblock hydrovolcanism_generator

[trail horizon]

Looking at the aisles i see e and o in the predicates but not in the aisles

[woeful plinth]

O is in the center of the top layer, E is not in a predicate but if you mean I there are 2 in the second layer in the center isle, one on the left and one on the right

oh but F is a predicate that is not in isles, that is true

[trail horizon]

Very important it can match all

[woeful plinth]

I'll try with the F removed from predicates, but the odd thing is when it does launch 50% of the time, the multi will form and run, I'll try removing the F and seeing if it still throws though

[trail horizon]

Yeah, thats just what happens

A bit annoying

[woeful plinth]

Thanks, will try a few relaunches

[trail horizon]

Also i made this for annoying to type out multis

%t multiblock<maker

[fervent kraken]

:warning: The tag name must consist of letters (A-Z, a-z), numbers, _ or -, and must be 32 characters or less.

[trail horizon]

%t multiblock_maker

[fervent kraken]

phoenixvine

Multiblock Program For Translating Json and Nbt Structure FIles Into Multiblock Aisles.
To use it double click on file (after you have python installed), then you can either paste in the contents of a json file and click generate, or import a file from your pc.
You also need to run python -m pip install NBT in your terminal or command prompt.
You can use both json and .nbt files.
You can also mirror and rotate the structures inside the program.
To get structure json files, use the copy/paste ...

[[Jump to Message]](#modern-addons message)

From #modern-addons · Dec 9, 2025, 9:49 PM

[woeful plinth]

I saw that while searching around for a fix for this, I'll be trying that out later for sure, will make it much easier to build in game and just generate isles for large multis, ty

[trail horizon]

Is the issue seeming to be fixed?

[woeful plinth]

Seemingly not, still same startup crash during registry, with that same line in the log for

Suppressed: java.lang.IllegalStateException: missing pattern while creating multiblock hydrovolcanism_generator

Multi registry now looks like

This is the only thing I've had issues like this with, and it's also the only generator, meaning the only multi I have that uses

.setEUIO('out')
.generator(true)
.regressWhenWaiting(false)

and also has empty
.recipeModifiers()

Those are the only stand outs to me compared to others I have

[trail horizon]

Wait, noRecipeModifiers()

Youre still calling modifiers and its expecting them

[woeful plinth]

Should I remove completely, set to .noRecipeModifiers(), or just throw in an OC method?

[trail horizon]

2 or 3. Your choice

[woeful plinth]

will try .noRecipeModifier() and see

[woeful plinth]

Ok that seems to be it, unless I'm on a lucky spree but 3 startups in a row with no crashes, which is more than I ever had before, going to assume the empty recipeModifiers was the culprit, thank you

[trail horizon]

Also was f. We solved both issues at once

🫡

[woeful plinth]

Marked as resolved

[trail horizon]

If you have any more issues feel free to ping me. Ill help if I can