Merge branch 'release-v1.15.0' of github.com:matrix-org/synapse into dinsic-release-v1.15.x

* 'release-v1.15.0' of github.com:matrix-org/synapse: (55 commits)
  1.15.0
  Fix some attributions
  Update CHANGES.md
  1.15.0rc1
  Revert "1.15.0rc1"
  1.15.0rc1
  Fix bug in account data replication stream. (#7656)
  Convert the registration handler to async/await. (#7649)
  Accept device information at the login fallback endpoint. (#7629)
  Convert user directory handler and related classes to async/await. (#7640)
  Add an option to disable autojoin for guest accounts (#6637)
  Clarifications to the admin api documentation (#7647)
  Update to the stable SSO prefix for UI Auth. (#7630)
  Fix type information on `assert_*_is_admin` methods (#7645)
  Remove some unused constants. (#7644)
  Typo fixes.
  Allow new users to be registered via the admin API even if the monthly active user limit has been reached (#7263)
  Add device management to admin API (#7481)
  Attempt to fix PhoneHomeStatsTestCase.test_performance_100 being flaky. (#7634)
  Support CS API v0.6.0 (#6585)
  ...

1 files changed, 12 insertions, 0 deletions

diff --git a/synapse/util/async_helpers.py b/synapse/util/async_helpers.py

index 581dffd8a0..f7af2bca7f 100644
--- a/synapse/util/async_helpers.py
+++ b/synapse/util/async_helpers.py
@@ -225,6 +225,18 @@ class Linearizer(object):
             {}
         )  # type: Dict[str, Sequence[Union[int, Dict[defer.Deferred, int]]]]
 
+    def is_queued(self, key) -> bool:
+        """Checks whether there is a process queued up waiting
+        """
+        entry = self.key_to_defer.get(key)
+        if not entry:
+            # No entry so nothing is waiting.
+            return False
+
+        # There are waiting deferreds only in the OrderedDict of deferreds is
+        # non-empty.
+        return bool(entry[1])
+
     def queue(self, key):
         # we avoid doing defer.inlineCallbacks here, so that cancellation works correctly.
         # (https://twistedmatrix.com/trac/ticket/4632 meant that cancellations were not