Fix 404 on /profile when the display name is empty but not the avatar (#16012)

changelog.d/16012.bugfix

@@ -0,0 +1 @@
+Fix 404 not found code returned on profile endpoint when the display name is empty but not the avatar URL.

synapse/handlers/profile.py

@@ -68,7 +68,7 @@ class ProfileHandler:
 
         if self.hs.is_mine(target_user):
             profileinfo = await self.store.get_profileinfo(target_user)
-            if profileinfo.display_name is None:
+            if profileinfo.display_name is None and profileinfo.avatar_url is None:
                 raise SynapseError(404, "Profile was not found", Codes.NOT_FOUND)
 
             return {

tests/handlers/test_profile.py

@@ -179,6 +179,16 @@ class ProfileTestCase(unittest.HomeserverTestCase):
 
         self.assertEqual("http://my.server/me.png", avatar_url)
 
+    def test_get_profile_empty_displayname(self) -> None:
+        self.get_success(self.store.set_profile_displayname(self.frank, None))
+        self.get_success(
+            self.store.set_profile_avatar_url(self.frank, "http://my.server/me.png")
+        )
+
+        profile = self.get_success(self.handler.get_profile(self.frank.to_string()))
+
+        self.assertEqual("http://my.server/me.png", profile["avatar_url"])
+
     def test_set_my_avatar(self) -> None:
         self.get_success(
             self.handler.set_avatar_url(