From 62a7289133840b4f4a55844b4f24ec664c3d917b Mon Sep 17 00:00:00 2001 From: Richard van der Hoff <1389908+richvdh@users.noreply.github.com> Date: Tue, 31 Mar 2020 13:09:16 +0100 Subject: Fix a bug which could cause incorrect 'cyclic dependency' error. (#7178) If there was an exception setting up one of the attributes of the Homeserver god object, then future attempts to fetch that attribute would raise a confusing "Cyclic dependency" error. Let's make sure that we clear the `building` flag so that we just get the original exception. Ref: #7169 --- changelog.d/7178.bugfix | 1 + synapse/server.py | 22 ++++++++++------------ 2 files changed, 11 insertions(+), 12 deletions(-) create mode 100644 changelog.d/7178.bugfix diff --git a/changelog.d/7178.bugfix b/changelog.d/7178.bugfix new file mode 100644 index 0000000000..35ea645d75 --- /dev/null +++ b/changelog.d/7178.bugfix @@ -0,0 +1 @@ +Fix a bug which could cause incorrect 'cyclic dependency' error. diff --git a/synapse/server.py b/synapse/server.py index cd86475d6b..9228e1c892 100644 --- a/synapse/server.py +++ b/synapse/server.py @@ -583,24 +583,22 @@ def _make_dependency_method(depname): try: builder = getattr(hs, "build_%s" % (depname)) except AttributeError: - builder = None + raise NotImplementedError( + "%s has no %s nor a builder for it" % (type(hs).__name__, depname) + ) - if builder: - # Prevent cyclic dependencies from deadlocking - if depname in hs._building: - raise ValueError("Cyclic dependency while building %s" % (depname,)) - hs._building[depname] = 1 + # Prevent cyclic dependencies from deadlocking + if depname in hs._building: + raise ValueError("Cyclic dependency while building %s" % (depname,)) + hs._building[depname] = 1 + try: dep = builder() setattr(hs, depname, dep) - + finally: del hs._building[depname] - return dep - - raise NotImplementedError( - "%s has no %s nor a builder for it" % (type(hs).__name__, depname) - ) + return dep setattr(HomeServer, "get_%s" % (depname), _get) -- cgit 1.4.1