Crash with 'Get Location at Spline Point' from array [+REPRO STEPS]

[Slavq]

This crash destroys my project and I can’t do anything, please fix it, I’ll help the best I can.

Repro steps:

1. Create a blueprint. Create an array of Spline Components. Then, in Construction Script:

2. Compile it, now it will crash with:

Assertion failed: (Index >= 0) &
(Index < ArrayNum)
[File:D:\Build++UE4+Release-4.13+Compile\Sync\Engine\Source\Runtime\Core\Public\Containers\Array.h]
[Line: 833] Array index out of
bounds: -1 from an array of size 0

… + For example, this doesn’t crash:

I’ve also sent a lot of crash reports regarding this.
Please fix this, thanks!

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Update: The repro steps are even simpler, it doesn’t have to be an array:
Add Spline Component, call ‘Clear Spline Points’ on it (crashes both with ‘Update Spline’ ON & OFF) and then get ‘Get Location at Time’ from it and try to print it (just like on the screens)

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Update 2: Alternative, even simpler repro:

This will crash when trying to compile.

[Slavq]

Update: The repro steps are even simpler, it doesn’t have to be an array:

Add Spline Component, call ‘Clear Spline Points’ on it (crashes both with ‘Update Spline’ ON & OFF) and then get ‘Get Location at Time’ from it and try to print it (just like on the screens)

[Slavq]

Update 2: Alternative, even simpler repro:

This will crash when trying to compile.

[Sean_L]

Hey Slavq,

I’ve attempted to reproduce this using all three of the methods described, but I have not seen a crash occur.

Could you please cause the crash to occur again and provide your Machine ID from the Crash Reporter window?

Are you using a binary or source build of the editor?

Are you working in 4.13 Preview 3?

[Slavq]

Sure, Machine ID: A7C3F0D1475F6BF6DA8AE980C167C7D3

I’m using a binary build, with no custom engine modifications, I also don’t use any plugins.

Yes, I’m working in 4.13 Preview 3.

(Now I’ve crashed with this simplest repro, Add Spline Component → Remove Spline Point in Construction Script + Compile)

[Sean_L]

Hey Slavq,

After further investigation, I was able to reproduce the crash in the 4.13 Preview 3 binary. However, it appears to have been fixed shortly after the Preview was released, so expect to see the fix in the next release.

If you decide to use a source build, you can merge this commit into your engine to resolve the issue: https://github.com/EpicGames/UnrealEngine/commit/3283cdeeecfabffd99547b33be6184a670d547ff

Have a great day

[Slavq]

That’s great to know, thank you!

[Slavq]

Update:
It crashes with the same error after trying to Fix Up Redirectors at any folder. I don’t know if I should make a new report for this or report it here, as it is the exact same error:

Assertion failed: (Index >= 0) &
(Index < ArrayNum)
[File:D:\Build++UE4+Release-4.13+Compile\Sync\Engine\Source\Runtime\Core\Public\Containers\Array.h]
[Line: 833] Array index out of
bounds: -1 from an array of size 0

… Something is still wrong on 833 line of Array class.
… And I’m not sure how I can help to narrow down this issue, since it happens after trying to Fix Up Redirectors, not from any particular blueprint…

Update 2: I’ve disconnected construction script of one of my biggest blueprints and now it doesn’t crash after clicking Fix Up Redirectors, I’ll start investigating from there…

[Slavq]

… I’ve clicked Fix Up Redirectors with this construction script disabled, then enabled it again, and now ‘Fix Up Redirectors’ doesn’t do anything, so… Maybe it’s fixed? Anyway, I can’t invoke the crash anymore, so… Well, to the next crash then If you need any more info or investigation on my side, please ask.