From 7dbac123f98a2d59d09a63efe4543ee850a8d630 Mon Sep 17 00:00:00 2001
From: Hugh Nimmo-Smith <hughns@users.noreply.github.com>
Date: Tue, 22 Aug 2023 12:42:08 +0100
Subject: [PATCH] Disallow user_consent where experimental MSC3861 is enabled
 (#16127)

---
 changelog.d/16127.bugfix              |  1 +
 synapse/config/experimental.py        |  7 +++++++
 tests/config/test_oauth_delegation.py | 16 ++++++++++++++++
 3 files changed, 24 insertions(+)
 create mode 100644 changelog.d/16127.bugfix

diff --git a/changelog.d/16127.bugfix b/changelog.d/16127.bugfix
new file mode 100644
index 000000000..0308fdfd4
--- /dev/null
+++ b/changelog.d/16127.bugfix
@@ -0,0 +1 @@
+User consent features cannot be enabled when using experimental MSC3861.
diff --git a/synapse/config/experimental.py b/synapse/config/experimental.py
index ac9449b18..d4cf9a055 100644
--- a/synapse/config/experimental.py
+++ b/synapse/config/experimental.py
@@ -173,6 +173,13 @@ class MSC3861:
                 ("enable_registration",),
             )
 
+        # We only need to test the user consent version, as if it must be set if the user_consent section was present in the config
+        if root.consent.user_consent_version is not None:
+            raise ConfigError(
+                "User consent cannot be enabled when OAuth delegation is enabled",
+                ("user_consent",),
+            )
+
         if (
             root.oidc.oidc_enabled
             or root.saml2.saml2_enabled
diff --git a/tests/config/test_oauth_delegation.py b/tests/config/test_oauth_delegation.py
index f57c813a5..35f7b85dc 100644
--- a/tests/config/test_oauth_delegation.py
+++ b/tests/config/test_oauth_delegation.py
@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import os
 from unittest.mock import Mock
 
 from synapse.config import ConfigError
@@ -167,6 +168,21 @@ class MSC3861OAuthDelegation(TestCase):
         with self.assertRaises(ConfigError):
             self.parse_config()
 
+    def test_user_consent_cannot_be_enabled(self) -> None:
+        tmpdir = self.mktemp()
+        os.mkdir(tmpdir)
+        self.config_dict["user_consent"] = {
+            "require_at_registration": True,
+            "version": "1",
+            "template_dir": tmpdir,
+            "server_notice_content": {
+                "msgtype": "m.text",
+                "body": "foo",
+            },
+        }
+        with self.assertRaises(ConfigError):
+            self.parse_config()
+
     def test_password_config_cannot_be_enabled(self) -> None:
         self.config_dict["password_config"] = {"enabled": True}
         with self.assertRaises(ConfigError):