Unreal Engine Issues

UE-88414

Blueprint Variables can become re-linked to default values.

Blueprint Variables can become re-linked to default values.

Developer Notes


There is no dirty bit for modified properties in Unreal. The value is 'delta serialized', compared against the value in the archetype. If the value in the archetype is changed to a new value that is the same as some previously modified instances then those instances will save as 'no delta' / no change against their archetype.

Description

Editor resets Per instance values if the parent was set to matching one

Steps to Reproduce
  1. Create an Actor BP and create a variable (int for example)
  2. Make the Variable Instance Editable
  3. Place the BP in the level and Set your variable to a new value (yellow arrow will appear)
  4. Back in the BP set the default to the same as the new value you set in previous step.
  5. Compile - yellow arrow will disappear (blueprint no longer considers value modified and now reverts to default linked behavior)
  6. In BP - Change the default

Result: The values are linked

Expected: Once modified, a variable is not linked to changes in default values

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Non-Issue
ComponentUE - Gameplay - Blueprint
Affects Versions4.23.1, 4.24.2
CreatedFeb 10, 2020
ResolvedFeb 11, 2020
UpdatedFeb 12, 2020