C#•3w ago

✅ Creditable usage for `goto`?

I don't think it needs further explanation, basically the goal is to catch any exceptions that might be thrown from inner functions that get called, but to also allow your own exceptions to be thrown when validation fails. Any thoughts? A)

public static int Method()
{
    try
    {
        int meow = 26;

        // ... other logic

        if (meow == 12)
            throw new MyException1();

        if (meow == 21)
            throw new MyException2();

        if (meow == 126)
            throw new MyException3();

        return meow * 2;
    }
    catch (MyException1)
    {
        throw; // Allow mine
    }
    catch (MyException2)
    {
        throw; // Allow mine
    }
    catch (MyException3)
    {
        throw; // Allow mine
    }
    catch
    {
        // Handle gracefully
        return 0;
    }
}

public static int Method()
{
    try
    {
        int meow = 26;

        // ... other logic

        if (meow == 12)
            throw new MyException1();

        if (meow == 21)
            throw new MyException2();

        if (meow == 126)
            throw new MyException3();

        return meow * 2;
    }
    catch (MyException1)
    {
        throw; // Allow mine
    }
    catch (MyException2)
    {
        throw; // Allow mine
    }
    catch (MyException3)
    {
        throw; // Allow mine
    }
    catch
    {
        // Handle gracefully
        return 0;
    }
}

public static int Method()
{
    try
    {
        int meow = 26;

        // ... other logic

        if (meow == 12)
            goto error1;

        if (meow == 21)
            goto error2;

        if (meow == 126)
            goto error3;

        return meow * 2;
    }
    catch
    {
        // Handle gracefully
        return 0;
    }

error1:
    throw new MyException1();

error2:
    throw new MyException2();

error3:
    throw new MyException3();
}

public static int Method()
{
    try
    {
        int meow = 26;

        // ... other logic

        if (meow == 12)
            goto error1;

        if (meow == 21)
            goto error2;

        if (meow == 126)
            goto error3;

        return meow * 2;
    }
    catch
    {
        // Handle gracefully
        return 0;
    }

error1:
    throw new MyException1();

error2:
    throw new MyException2();

error3:
    throw new MyException3();
}

public static int Method()
{
    try
    {
        int meow = 26;

        // ... other logic

        if (meow == 12)
            throw new MyException1();

        if (meow == 21)
            throw new MyException2();

        if (meow == 126)
            throw new MyException3();

        return meow * 2;
    }
    catch (Exception e) when (e is not MyException1 and not MyException2 and not MyException3)
    {
        // Handle gracefully
        return 0;
    }
}

public static int Method()
{
    try
    {
        int meow = 26;

        // ... other logic

        if (meow == 12)
            throw new MyException1();

        if (meow == 21)
            throw new MyException2();

        if (meow == 126)
            throw new MyException3();

        return meow * 2;
    }
    catch (Exception e) when (e is not MyException1 and not MyException2 and not MyException3)
    {
        // Handle gracefully
        return 0;
    }
}

36 Replies

Unknown User•3w ago

Message Not Public

canton7•3w ago

Wat? No, custom exceptions are great I'd go with A. Yes B's more "clever" and takes fewer lines, but A's more consistent with what people are used to seeing

AnarOP•3w ago

hold on, I totally forgot about the when clause

canton7•3w ago

I think when would make it harder to read

AnarOP•3w ago

catch (Exception e) when (e is not MyException)
{
    // Handle gracefully
    return 0;
}

catch (Exception e) when (e is not MyException)
{
    // Handle gracefully
    return 0;
}

Like so?

Unknown User•3w ago

Message Not Public

AnarOP•3w ago

Pretty legit imo but what if there are more exceptions to be taken care of

canton7•3w ago

I like when for taking logic out of the body of the catch, but not for removing another catch altogether

Unknown User•3w ago

Message Not Public

canton7•3w ago

This is hardy "complex things". This is bread-and-butter error handling

AnarOP•3w ago

I added yours to the post

Unknown User•3w ago

Message Not Public

AnarOP•3w ago

catch (Exception e) when (e is not MyException1 and not MyException2 and not MyException3) :harold:

canton7•3w ago

Use base classes, properties, etc. catch (ValidationExceptionBase)

AnarOP•3w ago

yup that does seem to solve most of the problems

canton7•3w ago

catch (ValidationExceptionBase e) when (e.IsRecoverable) or something etc

AnarOP•3w ago

but in my real case, the other exceptions that need to be caught already inherit from the same base, and some of them I cannot even edit/change (they are not from my code base)

canton7•3w ago

catch (Exception e) when (e is IValidationException)

AnarOP•3w ago

anything but goto? :catfine:

canton7•3w ago

It's not that goto is always horrible, it's that people aren't used to seeing it used, and don't know how to easily spot the common usage patterns Code should be obviously correct

AnarOP•3w ago

right is there no permission to open a poll or something?

Unknown User•3w ago

Message Not Public

AnarOP•3w ago

:catderp: not really what I wanted but obviously the duck

Unknown User•3w ago

Message Not Public

hamarb123•3w ago

or use a base type / interface / etc., or do catch (Exception e) when (e is not (MyException1 or MyException2 or MyException3))

AnarOP•3w ago

I now realize it is not a duck but something called "dodo" think I'm gonna go with the latter option too in the end

Unknown User•3w ago

Message Not Public

MODiX•3w ago

If you have no further questions, please use /close to mark the forum thread as answered

AnarOP•3w ago

I'll wait a couple hours in case somebody new hops in, gonna close it dw

hamarb123•3w ago

i mean, my real opinion is a) don't throw exceptions you didn't need to start with, b) catching all exceptions & discarding like that is quite sus, c) i don't mind goto (but not convinced it's really needed here tbh)

canton7•3w ago

It's no different to calling a helper method which throws the exception

hamarb123•3w ago

not that this really matters - but i mean, it is different - you wouldn't say if/goto is no different to an if/else, even when you can get the same IL from it

canton7•3w ago

I mean, putting the whole body of the try (or some significant subset) into a helper method What if throwing the exception needs a bunch of local state, which is only available at the point that the exception is thrown? Although, replace your enum with constructing (but not throwing) the exception, and that can work well I mean, if you had a method which called a bunch of other methods in a try, you wouldn't complain about one of those methods throwing an exception and you catching it. Inlining those methods directly into your try should make no difference

AnarOP•3w ago

then I'd say: for a very short and simple case, C is better; but if some additional steps need to be executed for each exception type, then B. Snippet A looks awkward to me too (throw X -> catch X -> throw)

ティナ•3w ago

int Func(){
  int ret;
  try{ ret=Func2(); }
  catch(RecoverableError e){ ret=100; }
  /// let FatalError throw
  try{ ret=Func3(ret); }
  catch(RecoverableError e){ ret=100; }
  return ret;
}

int Func(){
  int ret;
  try{ ret=Func2(); }
  catch(RecoverableError e){ ret=100; }
  /// let FatalError throw
  try{ ret=Func3(ret); }
  catch(RecoverableError e){ ret=100; }
  return ret;
}

? i dont really think a single big try-catch box is good fit, cconsider:

public static int Method(){
    try{
        int meow = 26;
        meow=Func(meow); // throw
        // ... other logic
        if (meow == 12)
            throw new MyException1();
        if (meow == 21)
            throw new MyException2();
        if (meow == 126)
            throw new MyException3();
        return meow * 2;
    } catch (Exception e) when (e is not MyException1 and not MyException2 and not MyException3){
        // Handle gracefully
        return 0;
    }
}

public static int Method(){
    try{
        int meow = 26;
        meow=Func(meow); // throw
        // ... other logic
        if (meow == 12)
            throw new MyException1();
        if (meow == 21)
            throw new MyException2();
        if (meow == 126)
            throw new MyException3();
        return meow * 2;
    } catch (Exception e) when (e is not MyException1 and not MyException2 and not MyException3){
        // Handle gracefully
        return 0;
    }
}

which is the same as

public static int Method(){
    int meow = 26;
    try{
      meow=Func(meow); // throw
    }catch(Exception e){
      return 0; // or other handling
      goto Return0;
    }
    // ... other logic
    if (meow == 12)
        throw new MyException1();
    if (meow == 21)
        throw new MyException2();
    if (meow == 126)
        throw new MyException3();
    return meow * 2;
Return0: return 0;
}

public static int Method(){
    int meow = 26;
    try{
      meow=Func(meow); // throw
    }catch(Exception e){
      return 0; // or other handling
      goto Return0;
    }
    // ... other logic
    if (meow == 12)
        throw new MyException1();
    if (meow == 21)
        throw new MyException2();
    if (meow == 126)
        throw new MyException3();
    return meow * 2;
Return0: return 0;
}

AnarOP•3w ago

I see what you mean splitting it into two try-catch blocks also solves the issue in my case thanks for all of your suggestions :)

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✅ Creditable usage for `goto`?

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