Revert "Drop support for delegating email validation (#13192)" (#13406)

Reverts commit fa71bb18b527d1a3e2629b48640ea67fff2f8c59, and tweaks documentation.

Signed-off-by: 3nprob <git@3n.anonaddy.com>

1 files changed, 10 insertions, 4 deletions

diff --git a/synapse/config/registration.py b/synapse/config/registration.py
index 685a0423c5..01fb0331bc 100644
--- a/synapse/config/registration.py
+++ b/synapse/config/registration.py
@@ -13,6 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import argparse
+import logging
 from typing import Any, Optional
 
 from synapse.api.constants import RoomCreationPreset
@@ -20,11 +21,15 @@ from synapse.config._base import Config, ConfigError
 from synapse.types import JsonDict, RoomAlias, UserID
 from synapse.util.stringutils import random_string_with_symbols, strtobool
 
-NO_EMAIL_DELEGATE_ERROR = """\
-Delegation of email verification to an identity server is no longer supported. To
+logger = logging.getLogger(__name__)
+
+LEGACY_EMAIL_DELEGATE_WARNING = """\
+Delegation of email verification to an identity server is now deprecated. To
 continue to allow users to add email addresses to their accounts, and use them for
 password resets, configure Synapse with an SMTP server via the `email` setting, and
 remove `account_threepid_delegates.email`.
+
+This will be an error in a future version.
 """
 
 
@@ -59,8 +64,9 @@ class RegistrationConfig(Config):
 
         account_threepid_delegates = config.get("account_threepid_delegates") or {}
         if "email" in account_threepid_delegates:
-            raise ConfigError(NO_EMAIL_DELEGATE_ERROR)
-        # self.account_threepid_delegate_email = account_threepid_delegates.get("email")
+            logger.warning(LEGACY_EMAIL_DELEGATE_WARNING)
+
+        self.account_threepid_delegate_email = account_threepid_delegates.get("email")
         self.account_threepid_delegate_msisdn = account_threepid_delegates.get("msisdn")
         self.default_identity_server = config.get("default_identity_server")
         self.allow_guest_access = config.get("allow_guest_access", False)