From 6374ca40c2ff3d2eaa41af5ebf4f8324522ecb84 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Fri, 27 Sep 2019 15:58:14 +0100
Subject: [PATCH] Update

---
 tests/patch_inline_callbacks.py | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/tests/patch_inline_callbacks.py b/tests/patch_inline_callbacks.py
index 5ef0aff0c..a35a1d330 100644
--- a/tests/patch_inline_callbacks.py
+++ b/tests/patch_inline_callbacks.py
@@ -15,7 +15,6 @@
 
 from __future__ import print_function
 
-import inspect
 import functools
 import sys
 
@@ -32,6 +31,8 @@ def do_patch():
     from synapse.logging.context import LoggingContext
 
     orig_inline_callbacks = defer.inlineCallbacks
+    if hasattr(orig_inline_callbacks, "patched_by_synapse"):
+        return
 
     def new_inline_callbacks(f):
         @functools.wraps(f)
@@ -100,13 +101,20 @@ def do_patch():
         return wrapped
 
     defer.inlineCallbacks = new_inline_callbacks
+    new_inline_callbacks.patched_by_synapse = True
 
 
 def _check_yield_points(f, changes, start_context):
+    """Wraps a generator that is about to passed to defer.inlineCallbacks
+    checking that after every yield the log contexts are correct.
+    """
+
     from synapse.logging.context import LoggingContext
 
     @functools.wraps(f)
     def check_yield_points_inner(*args, **kwargs):
+        expected_context = start_context
+
         gen = f(*args, **kwargs)
 
         last_yield_line_no = 1
@@ -119,12 +127,13 @@ def _check_yield_points(f, changes, start_context):
                 else:
                     d = gen.send(result)
             except (StopIteration, defer._DefGen_Return) as e:
-                if LoggingContext.current_context() != start_context:
+                if LoggingContext.current_context() != expected_context:
                     # This happens when the context is lost sometime *after* the
                     # final yield and returning. E.g. we forgot to yield on a
                     # function that returns a deferred.
                     err = (
-                        "%s returned and changed context from %s to %s, in %s between %d and end of func"
+                        "Function %r returned and changed context from %s to %s,"
+                        " in %s between %d and end of func"
                         % (
                             f.__qualname__,
                             start_context,
@@ -134,7 +143,6 @@ def _check_yield_points(f, changes, start_context):
                         )
                     )
                     changes.append(err)
-                    # print(err, file=sys.stderr)
                     # raise Exception(err)
                 return getattr(e, "value", None)
 
@@ -144,10 +152,8 @@ def _check_yield_points(f, changes, start_context):
                 result = Failure(e)
 
             frame = gen.gi_frame
-            if frame.f_code.co_name == "check_yield_points_inner":
-                frame = inspect.getgeneratorlocals(gen)["gen"].gi_frame
 
-            if LoggingContext.current_context() != start_context:
+            if LoggingContext.current_context() != expected_context:
                 # This happens because the context is lost sometime *after* the
                 # previous yield and *after* the current yield. E.g. the
                 # deferred we waited on didn't follow the rules, or we forgot to
@@ -164,9 +170,10 @@ def _check_yield_points(f, changes, start_context):
                     )
                 )
                 changes.append(err)
-                # print(err, file=sys.stderr)
                 # raise Exception(err)
 
+                expected_context = LoggingContext.current_context()
+
             last_yield_line_no = frame.f_lineno
 
     return check_yield_points_inner