Fix memory leak in logging.enable#152
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SergeyKanzhelev merged 3 commits intomicrosoft:developfrom Mar 18, 2019
CatalystCode:weakref
Merged
Fix memory leak in logging.enable#152SergeyKanzhelev merged 3 commits intomicrosoft:developfrom CatalystCode:weakref
SergeyKanzhelev merged 3 commits intomicrosoft:developfrom
CatalystCode:weakref
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The `logging.enable` function caches references to the LoggingHandler instances that it creates in a dictionary private to the module. This means that references to the handler objects survive even if they were removed from all loggers that referenced them, causing two undesirable side-effects: 1) The LoggingHandler instances created by `logging.enable` can never be reclaimed by the garbage collector. 2) Removing all references to the LoggingHandler from the logger doesn't mark the instrumentation key as "no longer used". This change fixes these issues by replacing the cache with a WeakValueDictionary: as soon as the last reference to the LoggingHandler is removed (e.g. when `some_logger.removeHandler(...)` is called), the WeakValueDictionary will also evict its cached entry.
SergeyKanzhelev
approved these changes
Mar 18, 2019
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The
logging.enablefunction caches references to theLoggingHandlerinstances that it creates in a dictionary private to the module.This means that references to the handler objects survive even if they were removed from all loggers that referenced them, causing two undesirable side-effects:
The
LoggingHandlerinstances created bylogging.enablecan never be reclaimed by the garbage collector.Removing all references to the
LoggingHandlerfrom the logger doesn't mark the instrumentation key as "no longer used" in thelogging.enablemodule.This change fixes these issues by replacing the cache with a
WeakValueDictionary: as soon as the last reference to theLoggingHandleris removed (e.g. whensome_logger.removeHandler(...)is called), theWeakValueDictionarywill also evict its cached entry.