How to copy item NBT into an item entity?

Question

Version 1.14.4:
I am trying to make a commands system that forces a player to drop whatever item is in their main hand. Because I can't use commands to make a player press Q and drop the original item, I need to copy the NBT into a new item on the ground and remove the old one from the player. I obviously want any NBT, including enchantments, names, lore, etc. to be copied over exactly.

I know that I can use /data to get the NBT from the SelectedItem of a player, and execute store can put NBT into an entity. However, /data get only returns numeric data, and execute store only allows me to set one NBT path at a time, so my plan of summoning a generic item on the ground and then just copying the NBT over (including the item ID) does not work.

Am I going about this wrong and there is a way to do this, or is this just impossible? My eventual plan is to implement this into a datapack, so if a method requires moving items into tile entities or something similar involving setting aside a space to spawn blocks in I'd rather avoid that. Of course, if you know a method like that by all means put it as an answer because someone else with the same question may find it useful for their situation.

Answer 1

You can copy the entire SelectedItem tag to the Item tag of the item entity:

/data modify entity @e[type=item,limit=1] Item set from entity @s SelectedItem

The existing item can be anything, it gets overwritten anything. Example summoning command:

/summon item ~ ~ ~ {Item:{id:"stone",Count:1}}

Just /summon item does not work, because it would be a stack of air with size 0.

More information about /data modify is in my other answer.