README

Author: ara4n

README.md

@@ -20,6 +20,46 @@ Currently very experimental and PoC.
 
 ### To use:
 
+Apply a minimal debugging patch to your dendrite's gomatrixserverlib:
+
+```patch
+diff --git a/event.go b/event.go
+index f0564fe..05ed845 100644
+--- a/event.go
++++ b/event.go
+@@ -1010,6 +1010,7 @@ func (e Event) Headered(roomVersion RoomVersion) HeaderedEvent {
+        return HeaderedEvent{
+                EventHeader: EventHeader{
+                        RoomVersion: roomVersion,
++                       DebugEventID: e.EventID(),
+                },
+                Event: e,
+        }
+diff --git a/headeredevent.go b/headeredevent.go
+index 414230c..c711436 100644
+--- a/headeredevent.go
++++ b/headeredevent.go
+@@ -13,10 +13,15 @@ import (
+ // this struct must have a "json:" name tag or otherwise the reflection
+ // code for marshalling and unmarshalling headered events will not work.
+ // They must be unique and not overlap with a name tag from the Event
+-// struct or otherwise panics may occur, so header  name tags are instead
++// struct or otherwise panics may occur, so header name tags are instead
+ // prefixed with an underscore.
+ type EventHeader struct {
+        RoomVersion RoomVersion `json:"_room_version,omitempty"`
++
++       // This is needed because otherwise Room V3+ events don't
++       // marshal an explicit EventID into their JSON, which makes debugging
++       // hard for things like TARDIS timetravel debugging.
++       DebugEventID string     `json:"_event_id,omitempty"`
+ }
+ 
+ // HeaderedEvent is a wrapper around an Event that contains information
+```
+
+And then to run it, tweak the config in src/index.js, and:
+
 ```
 yarn install
 yarn run start