Emails are not canonicalised on /_matrix/client/*/pushers/set

[sandhose]

Description

Emails sent to /pushers/set are not canonicalised, while they probably should.

Steps to reproduce

• choose an email with an uppercase letter in it, e.g. FooBar@example.com
• set that email to a user via the admin API. The email will end up normalized in the DB
• try to set an email pusher with the same email. It should work but doesn't and returns with an Email not found error

Version information

• Homeserver: other
• Version: 1.47.0
• Install method: Docker/Kubernetes
• Platform: N/A

---

Here, the pushkey should definitely be canonicalised for emails:

synapse/synapse/push/pusherpool.py

Lines 115 to 118 in 8c7a531

	if kind == "email":
	email_owner = await self.store.get_user_id_by_threepid("email", pushkey)
	if email_owner != user_id:
	raise SynapseError(400, "Email not found", Codes.THREEPID_NOT_FOUND)

using canonicalise_email:

synapse/synapse/util/threepids.py

Lines 66 to 69 in 8c7a531

	def canonicalise_email(address: str) -> str:
	"""'Canonicalise' email address
	Case folding of local part of email address and lowercase domain part
	See MSC2265, https://github.com/matrix-org/matrix-doc/pull/2265