Structure blocks create block updates, even if the block isn't altered.

The bug

Structure blocks cause block updates when loading the structure, even if the structure integrity is set to 0.

I haven't tested if it occurs when loading a structure void structure, but it may also be the case there.

Expected behaviour: non-changed blocksand "empty" areas give no block updates.

How to reproduce

1. Place a SAVE structure block and power it

   /setblock ~2 ~ ~-1 structure_block{posX:0,posY:0,posZ:0,mode:"SAVE",sizeX:1,sizeY:1,sizeZ:1,name:"mc-114396"}
   

2. Place blocks to detect a block update

   /setblock ~2 ~3 ~1 piston
   /setblock ~2 ~4 ~2 redstone_block
   

3. Place a LOAD structure block and power it

   /setblock ~2 ~ ~1 structure_block{posX:0,posY:2,posZ:0,mode:"LOAD",sizeX:1,sizeY:1,sizeZ:1,name:"mc-114396",integrity:0f}
   

   → You should see that the piston was updated and is not extended despite no block being placed

Code analysis

Based on 1.11.2 decompiled using MCP 9.35 rc1

The method net.minecraft.world.gen.structure.template.Template.addBlocksToWorld(World, BlockPos, ITemplateProcessor, PlacementSettings, int) updates the neighboors of a block regardless of whether it was placed or not.