Fix application service not being able to join remote federated room without a profile set

[MadLittleMods]

Fix application service not being able to join remote federated room without a profile set

Fix #4778

Complement tests: matrix-org/complement#399

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  (run the linters)

[MadLittleMods]

Same pattern that we already use in

synapse/synapse/handlers/message.py

Lines 640 to 652 in e714b8a

	try:
	if "displayname" not in content:
	displayname = await profile.get_displayname(target)
	if displayname is not None:
	content["displayname"] = displayname
	if "avatar_url" not in content:
	avatar_url = await profile.get_avatar_url(target)
	if avatar_url is not None:
	content["avatar_url"] = avatar_url
	except Exception as e:
	logger.info(
	"Failed to get profile information for %r: %s", target, e
	)

[MadLittleMods]

Feels like these profile functions would be better if they just returned None when there is no profile for the local user. Profiles aren't required.

• synapse/synapse/handlers/profile.py

  Lines 104 to 129 in e714b8a

  	async def get_displayname(self, target_user: UserID) -> Optional[str]:
  	if self.hs.is_mine(target_user):
  	try:
  	displayname = await self.store.get_profile_displayname(
  	target_user.localpart
  	)
  	except StoreError as e:
  	if e.code == 404:
  	raise SynapseError(404, "Profile was not found", Codes.NOT_FOUND)
  	raise
  	return displayname
  	else:
  	try:
  	result = await self.federation.make_query(
  	destination=target_user.domain,
  	query_type="profile",
  	args={"user_id": target_user.to_string(), "field": "displayname"},
  	ignore_backoff=True,
  	)
  	except RequestSendFailed as e:
  	raise SynapseError(502, "Failed to fetch profile") from e
  	except HttpResponseException as e:
  	raise e.to_synapse_error()
  	return result.get("displayname")

• synapse/synapse/handlers/profile.py

  Lines 201 to 225 in e714b8a

  	async def get_avatar_url(self, target_user: UserID) -> Optional[str]:
  	if self.hs.is_mine(target_user):
  	try:
  	avatar_url = await self.store.get_profile_avatar_url(
  	target_user.localpart
  	)
  	except StoreError as e:
  	if e.code == 404:
  	raise SynapseError(404, "Profile was not found", Codes.NOT_FOUND)
  	raise
  	return avatar_url
  	else:
  	try:
  	result = await self.federation.make_query(
  	destination=target_user.domain,
  	query_type="profile",
  	args={"user_id": target_user.to_string(), "field": "avatar_url"},
  	ignore_backoff=True,
  	)
  	except RequestSendFailed as e:
  	raise SynapseError(502, "Failed to fetch profile") from e
  	except HttpResponseException as e:
  	raise e.to_synapse_error()
  	return result.get("avatar_url")

[erikjohnston]

Yeah, I agree. Pretty much everywhere uses the same pattern as here, and we already return None if the user sets and then deletes their display name

[erikjohnston]

Happy for this to land as is, or to refactor calls to the profile store

[MadLittleMods]

Will merge for now ⏩

Thanks for the review @erikjohnston 🐹