Previously we only changed sequence on ownership change, this
cause a race condition between tabs where user could type for a
long time without being warned of an out of date draft.
This change is a radical change and we should watch closely.
Code was already in place to track sequence on the client so no
changes are needed there.
This is a major change to draft internals. Previously there were quite a
few cases where the draft system would say "draft saved", when in fact
we just skipped saving.
This commit ensures the draft system deals with draft ownership handover in
a predictable way.
For example:
- Window 1 editing draft
- Window 2 editing same draft at the same time
Previously we would allow window 1 and 2 to just fight on the same draft
each window overwriting the same draft over an over.
This commit introduces an ownership concept where either window 1 or 2 win
and user is prompted on the loser window to reload screen to correct the issue
This also corrects edge cases where a user could have multiple browser windows
open and posts in 1 window, later to post in the second window. Previously
drafts would break in the second window, this corrects it.
This change both speeds up specs (less strings to allocate) and helps catch
cases where methods in Discourse are mutating inputs.
Overall we will be migrating everything to use #frozen_string_literal: true
it will take a while, but this is the first and safest move in this direction
