[Python-Dev] Why not using "except: (...) raise" to cleanup on error?

Victor Stinner vstinner at redhat.com
Mon Jun 4 12:11:55 EDT 2018


I just read a recent bugfix in asyncio:


+ try:
+     await waiter
+ except Exception:
+     transport.close()
+     raise

Why only catching "except Exception:"? Why not also catching
KeyboardInterrupt or MemoryError? Is it a special rule for asyncio, or
a general policy in Python stdlib?

For me, it's fine to catch any exception using "except:" if the block
contains "raise", typical pattern to cleanup a resource in case of
error. Otherwise, there is a risk of leaking open file or not flushing
data on disk, for example.


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