Re: [Libguestfs] [libnbd PATCH v2 1/5] python: tests: Fix error handling

On Thu, Feb 3, 2022 at 10:26 PM Eric Blake <eblake(a)redhat.com&gt; wrote: > > Like a lot of the C examples, the aio copy test ignores read and write > errors in the completion callback, which can cause silent data > corruption. The failure in the test is not critical, but this is a bad > example that may be copied by developers to a real application. >

> @@ -36,6 +36,7 @@ def asynch_copy(src, dst): > # This callback is called when any pread from the source > # has completed. > def read_completed(buf, offset, error): > + assert not error This works for the test, since the test is not compiled to pyc file, which removes the asserts (like C -DNODBUG) by default when building rpms. If someone will copy this to a real application they will have no error checking. I would use: if error != 0: raise RuntimeError(f"read: {os.strerror(error)}") Which also teaches the reader that error is an errno value.