Duplicate of #9050

Rebased on 1.21.3

Something else that was brought up internally is the whole "display name" naming being outdated/confusing in general now. effectiveName is good for the new method on ItemStack, but we'd like this to go alongside improving ItemStack#displayName docs and replacing ItemMeta displayName methods with customName (since that's what it returns, but other data components can change or be the effective display name). Replace in this case means marking the old as obsolete and linking to the new

Can I move the ItemStack#displayName from the adventure patch to my patch? It ends up a bit uglier without that

Yeah sure

Applied the deprecation and made the replacement for ItemStack#displayName

I'm confused with what's going on in this diff, what kenny asked for was:

• Improve docs for ItemStack#displayName()
• Deprecate/obsolete ItemMeta#displayName(Component) and ItemMeta#displayName() in favor of new customName methods (also update the deprecation notice on the legacy methods to point to customName)
• Add ItemStack#effectiveName() method

ItemMeta#displayName(Component) and ItemMeta#displayName()

Oh, missed that he mentioned ItemMeta and didn't even think of it as this pr didn't touch item meta. Maybe I could just rollback the diff and this pr would just add the new api, and dealing with displayName methods in a separate pr? As personally I disagree with deprecation of a highly used method (I'm sure it's used in almost every plugin) in favor of making an unused by almost every plugin method reflect the mojang naming

Not a fan of deprecating the ItemMeta method either.
Yes its objectively wrong since two versions, but that thing has been called "display name" in vanilla too for ten years now and just spamming more deprecation will make more people simply ignore them.

I would just deprecate the ItemStack one because its borderline useless. And add a little note to the JD that this works slightly differently in vanilla nowadays.