Race-time condition from core layouts.cfm

[timsayshey]

Describe the bug
Unfortunately, this is a race-time condition coming from CFWheels, and I am unable to reproduce it. It happens in production on rare occasion.

It is triggered when I called usesLayout from my controller:
usesLayout("/layouts/blank");

Any idea how this error would be possible by looking at the framework code?
wheels/controller/layouts.cfm:46

Environment

• Ubuntu Server
• Lucee 5.3.9
• CFWheels 2.4.0

Error:

Error: 
Array index [4] out of range, array size is [3]

Location: 
wheels/controller/layouts.cfm:46
controllers/MyController.cfc:10
wheels/global/cfml.cfm:160
wheels/controller/processing.cfm:164
wheels/global/cfml.cfm:160
wheels/global/cfml.cfm:13
wheels/controller/processing.cfm:86
wheels/dispatch/functions.cfm:199
wheels/index.cfm:6
index.cfm:2
wheels/events/onrequest.cfm:4

[timsayshey]

layouts.cfm hadn't been changed in years until the syntax updates ticket that @chapmandu worked on.

I reverted back the syntax updates, I can't imagine how that would cause this bug but so far I haven't seen the error again so that's promising. I just have no idea how these changes would cause this issue.

Here's the commit I reverted back from:
7dabfd4

[timsayshey]

Nevermind, it's back 🤦🏻‍♂️

[timsayshey]

@neokoenig Any ideas? Is it possible the array could be modified somewhere else concurrently which would account for why CF counts 4 items in the array on one line then on the next only counts 3?

[neokoenig]

@neokoenig Any ideas? Is it possible the array could be modified somewhere else concurrently which would account for why CF counts 4 items in the array on one line then on the next only counts 3?

Not off the top of my head, but just wondering if it is actually a "blank" layout, then you could use usesLayout(false)? (might not be of course)

[timsayshey]

Thanks Tom! Fortunately, the layout file is actually blank. It just has <cfoutput>#includeContent()#</cfoutput>.

Just updated the code in prod, praying that fixes it 🙏

[timsayshey]

@neokoenig Ugh - Similar to the last error, except now it's saying Array index [5] out of range, array size is [4]

If you look at the code, this error should not be possible. Any other ideas?

[timsayshey]

I'm going to try changing the way we loop over the layouts array. Maybe that'll help:

[zainforbjs]

@timsayshey Is this issue fixed?