wholetrans/docs-matrix-spec
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

Note a more efficient computation of the auth difference. (#1119)

Browse source
This commit is contained in:
David Robertson 2022-06-15 12:32:58 +01:00 • committed by GitHub
parent 6792b7a9d6
commit a707266e50
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
2 changed files with 14 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

1
changelogs/room_versions/newsfragments/1119.clarification Normal file
View file

@ -0,0 +1 @@
For room version 2 through 10: Note a more efficient way to compute the auth difference during state resolution.

19
content/rooms/fragments/v2-state-res.md
View file

@ -47,13 +47,20 @@ 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 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.** **Auth difference.**
The *auth difference* is calculated by first calculating the full auth For each state *S<sub>i</sub>*, compute its full auth chain.
chain for each state *S*<sub>*i*</sub>, that is the union of the auth The *auth difference* is the set of events which belong to some, but not all,
chains for each event in *S*<sub>*i*</sub>, and then taking every event of these full auth chains. In symbols: if *F*(*S*) is the full auth
that doesn't appear in every auth chain. If *C*<sub>*i*</sub> is the chain of a collection of events *S*, the auth difference is
full auth chain of *S*<sub>*i*</sub>, then the auth difference is ∪<sub>*i*</sub> *F*(*S<sub>i</sub>*) - ∩<sub>*i*</sub> *F*(*S<sub>i</sub>*).
 ∪ *C*<sub>*i*</sub> −  ∩ *C*<sub>*i*</sub>.
This can be computed more efficiently as
*F*(*C*) - ∩<sub>*i*</sub> *F*(*S*<sub>*i* - *C*</sub>) ,
where *C* is the conflicted state set.
**Full conflicted set.** **Full conflicted set.**
The *full conflicted set* is the union of the conflicted state set and The *full conflicted set* is the union of the conflicted state set and