diff --git a/synapse/util/patch_inline_callbacks.py b/synapse/util/patch_inline_callbacks.py
index 5ef7190b14..b518dae256 100644
--- a/synapse/util/patch_inline_callbacks.py
+++ b/synapse/util/patch_inline_callbacks.py
@@ -107,6 +107,19 @@ def do_patch():
def _check_yield_points(f, changes, start_context):
"""Wraps a generator that is about to be passed to defer.inlineCallbacks
checking that after every yield the log contexts are correct.
+
+ Its perfectly valid for log contexts to change within a function, e.g. due
+ to new Measure blocks, so such changes are added to the given `changes`
+ list instead of triggering an exception.
+
+ Args:
+ f: generator function to wrap
+ changes (list[str]): A list of strings detailing how the contexts
+ changed within a function.
+ start_context (LoggingContext): The initial context we're expecting
+
+ Returns:
+ function
"""
from synapse.logging.context import LoggingContext
@@ -131,6 +144,10 @@ def _check_yield_points(f, changes, start_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.
+ #
+ # We don't raise here as its perfectly valid for contexts to
+ # change in a function, as long as it sets the correct context
+ # on resolving (which is checked separately).
err = (
"Function %r returned and changed context from %s to %s,"
" in %s between %d and end of func"
@@ -143,14 +160,14 @@ def _check_yield_points(f, changes, start_context):
)
)
changes.append(err)
- # raise Exception(err)
return getattr(e, "value", None)
frame = gen.gi_frame
if isinstance(d, defer.Deferred) and not d.called:
# This happens if we yield on a deferred that doesn't follow
- # the log context rules without wrappin in a `make_deferred_yieldable`
+ # the log context rules without wrappin in a `make_deferred_yieldable`.
+ # We raise here as this should never happen.
if LoggingContext.current_context() is not LoggingContext.sentinel:
err = (
"%s yielded with context %s rather than sentinel,"
@@ -162,8 +179,7 @@ def _check_yield_points(f, changes, start_context):
frame.f_code.co_filename,
)
)
- changes.append(err)
- # raise Exception(err)
+ raise Exception(err)
try:
result = yield d
@@ -171,10 +187,15 @@ def _check_yield_points(f, changes, start_context):
result = Failure(e)
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
# yield on a function between the two yield points.
+ #
+ # We don't raise here as its perfectly valid for contexts to
+ # change in a function, as long as it sets the correct context
+ # on resolving (which is checked separately).
err = (
"%s changed context from %s to %s, happened between lines %d and %d in %s"
% (
@@ -187,7 +208,6 @@ def _check_yield_points(f, changes, start_context):
)
)
changes.append(err)
- # raise Exception(err)
expected_context = LoggingContext.current_context()
|
