Is it a good approach to call return inside using {} statement?
I just want to know is it safe/ good approach to call return
inside a using
block.
For ex.
using(var scope = new TransactionScope())
{
// my core logic
return true; // if condition met else
return false;
scope.Complete();
}
We know the at the last most curly brace dispose()
will get called off. But what will be in the above case, since return
jumps the control out of the given scope (AFAIK)...
- Is my
scope.Complete()
get called? - And so for the scope's
dispose()
method.
It's perfectly safe to call return
inside your using
block, since a using block is just a try/finally
block.
In your example above after return true
, the scope will get disposed and the value returned. return false
, and scope.Complete()
will not get called. Dispose
however will be called regardless since it reside inside the finally block.
Your code is essentially the same as this (if that makes it easier to understand):
var scope = new TransactionScope())
try
{
// my core logic
return true; // if condition met else
return false;
scope.Complete();
}
finally
{
if( scope != null)
((IDisposable)scope).Dispose();
}
Please be aware that your transaction will never commit as there's no way to get to scope.Complete()
to commit the transaction.
That's fine - finally
clauses (which is what the closing curly brace of the using
clause does under the hood) always get executed when the scope is left, no matter how.
However, this is only true for statements that are in the finally block (which cannot be explicitly set when using using
). Therefore, in your example, scope.Complete()
would never get called (I expect the compiler to warn you about unreachable code though).
In general, it is a good approach. But in your case, if you return before calling the scope.Complete()
, it will just trash the TransactionScope. Depends to your design.
So, in this sample, Complete() is not called, and scope is disposed, assuming it is inheriting IDisposable interface.
scope.Complete should definitely be called before return
. Compiler will display a warning and this code will never be called.
Regarding return
itself - yes, it is safe to call it inside using
statement. Using is translated to try-finally block behind the scene and finally block is to be certainly executed.
In the example you have provided, there is a problem; scope.Complete()
is never called.
Secondly, it is not a good practice to use return
statement inside using
statements. Refer to the following:
using(var scope = new TransactionScope())
{
//have some logic here
return scope;
}
In this simple example, the point is that; the value of scope
will be null when using statement is finished.
So it is better not to return inside using statements.