Error: not invited when joining too quickly

[silkeh]

On the Matrix-IRCnet bridge some people have trouble sending a message to a person.
The cause seems to be that if the invited party joins too quickly, the inviting homeserver denies the join.
The bridge automatically joins, resulting in 307 ms between sending the invite and receiving the join.

The resulting response is SynapseError: 403 - You are not invited to this room.
log.txt contains the debug log for the two requests (creating/inviting and joining).

On the server, I see the following events:

| event_id                 | type                      | content
---------------------------+---------------------------+---------
 $14999418670pJBSM:slxh.eu | m.room.create             | {"creator":"@silex:slxh.eu"}
 $14999418681RDRYI:slxh.eu | m.room.member             | {"avatar_url":"mxc://slxh.eu/firYUbGCedTKEeYmayUSnKUz","displayname":"Silke","membership":"join"}
 $14999418682SbYPV:slxh.eu | m.room.power_levels       | {"ban":50,"events":{"m.room.avatar":50,"m.room.canonical_alias":50,"m.room.history_visibility":100,"m.room.name":50,"m.room.power_levels":100},"events_default":0,"invite":0,"kick":50,"redact":50,"state_default":50,"users":{"@_ircnet_^^_^^:irc.snt.utwente.nl":100,"@silex:slxh.eu":100},"users_default":0}
 $14999418693oWJMx:slxh.eu | m.room.join_rules         | {"join_rule":"invite"}
 $14999418704rTiYM:slxh.eu | m.room.history_visibility | {"history_visibility":"shared"}
 $14999418715zKlyB:slxh.eu | m.room.guest_access       | {"guest_access":"can_join"}
 $14999418736ROTWn:slxh.eu | m.room.member             | {"avatar_url":null,"displayname":"^^_^^ (IRC)","is_direct":true,"membership":"invite"}

The server then creates (and signs) the following event.
Note that the prev_events is actually one event too early.

{
	"auth_events": [
		["$14999418670pJBSM:slxh.eu", {
			"sha256": "h4wQhafYBJ0hw0pByePewTZ/Wisd1mlYYy7b3+jYjkw"
		}],
		["$14999418682SbYPV:slxh.eu", {
			"sha256": "lMBl4s8tP82N2cRY3AvmMeOpO4T8U0/YClTiQazi0V8"
		}],
		["$14999418693oWJMx:slxh.eu", {
			"sha256": "aEkbGx/4vEZ6dPdm/+5PdLSEhnq7U0uDqyUIWyihYxU"
		}]
	],
	"content": {
		"membership": "join"
	},
	"depth": 7,
	"event_id": "$14999418747tuojQ:slxh.eu",
	"hashes": {
		"sha256": "ZiMyi5EnmrKtVdUm0WpPmL6kD9EWLGhrDyKcDMcYZEU"
	},
	"origin": "slxh.eu",
	"origin_server_ts": 1499941874430,
	"prev_events": [
		["$14999418715zKlyB:slxh.eu", {
			"sha256": "VJCVgu/nkJJQ3/KAstVu/xbVyD8F+ve7iY4faRsje+U"
		}]
	],
	"prev_state": [],
	"room_id": "!pJHIzJXCnKbrJoTqKR:slxh.eu",
	"sender": "@_ircnet_^^_^^:irc.snt.utwente.nl",
	"signatures": {},
	"state_key": "@_ircnet_^^_^^:irc.snt.utwente.nl",
	"type": "m.room.member"
}

[MurzNN]

Seems I got same problem when inviting bots from other homeserver, here are logs:

2019-07-03 15:38:11,238 - synapse.http.matrixfederationclient - 401 - INFO - POST-3642- {PUT-O-367} [homeserver2.com] Sending request: PUT matrix://homeserver2.com/_matrix/federation/v2/invite/%21SgBFimbGVUVNLDYaJc%3Ahomeserver1.com/%24j0G6ruROEadC-1pCTN8eCkdZQAzYT9qlWsRI22k4Pt8; timeout 60.000000s
2019-07-03 15:38:11,609 - synapse.access.http.8008 - 233 - INFO - GET-3648- 82.162.163.148 - 8008 - Received request: GET /_matrix/federation/v1/make_join/%21SgBFimbGVUVNLDYaJc%3Ahomeserver2.com/%40voice2text%3Ahomeserver2.com?ver=1&ver=state-v2-test&ver=4&ver=3&ver=2
2019-07-03 15:38:11,705 - synapse.http.server - 85 - INFO - GET-3648- <XForwardedForRequest at 0x7f326e81bda0 method='GET' uri='/_matrix/federation/v1/make_join/%21SgBFimbGVUVNLDYaJc%3Ahomeserver1.com/%40voice2text%3Ahomeserver2.com?ver=1&ver=state-v2-test&ver=4&ver=3&ver=2' clientproto='HTTP/1.0' site=8008> SynapseError: 403 - You are not invited to this room.
2019-07-03 15:38:11,732 - synapse.access.http.8008 - 302 - INFO - GET-3648- 82.162.163.148 - 8008 - {homeserver2.com} Processed request: 0.123sec/0.000sec (0.008sec, 0.002sec) (0.009sec/0.019sec/3) 69B 403 "GET /_matrix/federation/v1/make_join/%21SgBFimbGVUVNLDYaJc%3Aru-matrix.org/%40voice2text%3Ahomeserver2.com?ver=1&ver=state-v2-test&ver=4&ver=3&ver=2 HTTP/1.0" "Synapse/0.99.5.2" [0 dbevts]

After adding 3 sec delay on remote bot side, it invites normally to my (new) room.

[MurzNN]

Same problem with https://github.com/progserega/voice2textMatrix bot, adding 1sec delay workaround works well.

[MadLittleMods]

Related to #10066