[BUG] Math expression is broken in 4.8

Hi, on OSX math expression is broken.
Tested on win64, math node works there

In project where i allready used math expression and converted entire project from 4.7.6 to 4.8 brokes my math expression, there is no input nodes, i can not input anything inside math expression (even if its simple x+ y there are no input nodes). I created new math expression and text says “UnexpectedTokenType” i change it to x + y and there are no input nodes, but i do get output node as float.

So, i created new project, added only math expression on level blueprint and name says UnexpectedTokenType with float input node. i change it to x + y and i get x + y input nodes as float. I delete name (empty function) and x + y stays there.

Hi wmbuRn,

I haven’t been able to reproduce any problems with math expression node. To test, I created a new project with a new Actor Blueprint. I created a math expression node and type “x + y” in Name field, which also added x + y to Expression field. I compiled and saved, then created a copy of project in 4.8.0. only difference I can see is that post conversion, Expression field now reads “(x + y)”, but otherwise all input and outputs remained intact.

I tried same thing with a new node in 4.8.0, and though fields default to “UnexpectedTokenType”, renaming Name or Expression fields creates a working node with all inputs and outputs as expected.

Upon re-reading your post, I also tried all of above in Level Blueprint, with same results.

Are there any steps that I may be missing to reproduce this?

No, all steps are there. If you tested it on OSX and it works, then probably i made some mistakes when updating engine. I never got x + y inside brackets. Thank you for your time

Yep, tested in OSX 10.10.3. Do you have a custom engine setup, have you edited source? Does this happen in binary version of 4.8 for you as well?

i have a version downloaded from Epic Games Launcher. First i downloaded 4.8p1 and then updated it to final. Will reinstall Engine and report back

Thanks, let me know what happens.

Hi wmbuRn,

Any luck?

Hi ,

I deleted everythig engine related and reinstalled engine version 4.7.6 and 4.8.1 (both were downloaded via EPic Games Launcher) and still no luck.
What i found out is that pow(x,2) does not have input node for X

I tried same expression (pow(x,2)), but math expression has expected input and output after updating project from 4.7.6 to 4.8.1 on Mac. I’m going to check with developers to see if they know anything that might cause this.

In meantime, would you mind zipping up a small test project, both 4.7.6 version and converted 4.8.1 version, and either attaching it here (a blank project with no starter content should be small enough) or uploading it somewhere like Google Drive or Dropbox and getting me a download link? Thanks!

A couple of additional questions:
Is this happening inside a function, and do you have an “x” local variable (or maybe an “x” input into function)?

Hi , i can’t give anything developed on work, even if its project that is not anyway connected to any ongoing project (company rules), at home i have windows and converting project from 4.7.6 to 4.8.1 works without problems. I have 2 functions that uses math expression, Same X is used and is input into function

Thanks wmbuRn!

It looks like there’s a problem in 4.8.1 with math expressions inside functions. I tried creating a new x + y Math Expression node inside a function that had an X input, and math node did not include X input. So a project converted from 4.7 to 4.8 would remove inputs in math expression nodes that share a name with function inputs. This will occur both on Mac and PC.

I tested this in our internal build as well, and it appears issue is already fixed, so this should no longer occur in a future release (probably 4.9). Thanks for report!