Crash when Model.PrimaryPart points to non-BasePart

Bug Reports Engine Bugs
#1

Reproduction Steps
Reproduction files:

  • repro-original.rbxm (973 Bytes)
    • This is the unmodified model file used as the base of the reproduction. It contains a Model and a BoolValue as root instances.
  • repro-decompressed.rbxm (956 Bytes)
    • A modification of repro-original.rbxm such that each chunk is encoded in decompressed form. This makes modifying the content of the file easier. Roblox will still decode this file correctly.
  • repro-modified.rbxm (956 Bytes)
    • A modification of repro-decompressed.rbxm, where the 759th byte is changed from 01 to 02. This causes the PrimaryPart property of the Model to point to the BoolValue instead of nothing.

To reproduce the crash, open a new place in Studio, and insert repro-modified.rbxm.

Expected Behavior
The file decoder either fails to decode the file, producing an error, or the cause of the error is silently discarded.

Actual Behavior
The process crashes when the file is decoded.

Issue Area: Engine
Issue Type: Crashing
Impact: Very High
Frequency: Constantly
A private message is associated with this bug report

5 Likes
#2

It looks like a change to error handling/reporting has led to this regression. I think this happens for any ref property where IsA fails, and possibly some other cases.

6 Likes