Filip/matrix-spec
1
0
Fork 0
mirror of https://github.com/matrix-org/matrix-spec synced 2026-03-26 04:54:10 +01:00
Code Issues Actions 1 Packages Projects Releases Wiki Activity

Note a more efficient computation of the auth difference.

Browse source
This commit is contained in:
David Robertson 2022-06-13 15:59:34 +01:00
parent 10615c5385
commit 30f6dc2293
No known key found for this signature in database
GPG key ID: 903ECE108A39DEDD
1 changed files with 10 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

16
content/rooms/fragments/v2-state-res.md
View file

@ -45,15 +45,19 @@ whereas the conflicted state set may associate multiple events to the same key.
The *auth chain* of an event *E* is the set containing all of *E*'s auth events,
all of *their* auth events, and so on recursively, stretching back to the
start of the room. Put differently, these are the events reachable by walking
the graph induced by an event's `auth_events` links.
the graph induced by an event's `auth_events` links. If *S* is a collection of
events, the *full auth chain of S* is the union of the auth chains of every
event *E* in *S*.
**Auth difference.**
The *auth difference* is calculated by first calculating the full auth
chain for each state *S*<sub>*i*</sub>, that is the union of the auth
chains for each event in *S*<sub>*i*</sub>, and then taking every event
that doesn't appear in every auth chain. If *C*<sub>*i*</sub> is the
full auth chain of *S*<sub>*i*</sub>, then the auth difference is
 ∪ *C*<sub>*i*</sub> −  ∩ *C*<sub>*i*</sub>.
chain for each state *S*<sub>*i*</sub>, and then discarding the events
belonging to each full auth chain. In symbols: if *C*(*S*) is the full auth
chain of a collection of events *S*, the auth difference is
∪<sub>*i*</sub> *C*(*S<sub>i*</sub>) - ∩<sub>*i*</sub> *C*(*S<sub>i</sub>*).
This can be [computed more efficiently](https://github.com/matrix-org/matrix-spec/issues/1118) as
*C*(*F*) - ∩<sub>*i*</sub> *C*(*S<sub>i* - *F*) ,
where *F* is the full conflicted set.
**Full conflicted set.**
The *full conflicted set* is the union of the conflicted state set and