Why exception doesn't supress ssl.SSLError


I want to supress all expection by calling:

        doSomething2() # exception is raised
    except Exception:
        print("expection thrown, test should pass!")

In doSomething2() there are some exceptions raised like

E   ssl.SSLError: [SSL: NO_CIPHERS_AVAILABLE] no ciphers available (_ssl.c:1076) 

Why except Exception doesn’t supress all exceptions ?

Asked By: kkkl kkl



So we have the following code:

    doSomething2() # expection is raised
except Exception:
    print("expection thrown, test should pass!")

and … apparently … the exception handler is not catching ssl.SSLError.

How can this be? After all SSLError is a subclass of OSError which is in turn a subclass of Exception. So, the handler should catch an SSLError.

Here are all of the possible explanations that I can think of:

  • SSLError is not thrown at all. We can exclude that as you have shown us evidence that it is thrown.

  • The SSLError is thrown but caught further up the stack. For example, if doSomething2() does something like this:

      def something2():
             # attempt to open an HTTPS connection
         catch OSError:
             # report the exception

    That exception handler will catch the SSLError … and the outer handler won’t ever see it or be able to suppress it.

  • The SSLError is thrown on a different thread stack. Uncaught exceptions thrown by one thread don’t automatically propagate to a different stack. Instead, they will just terminate the thread that threw the exception.

  • Something has monkey-patched SSLError to change its superclass. This seems so perverse that I’d call this implausible. But it may be technically possible.

Answered By: Stephen C
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