Use CancellationToken.ThrowIfCancellationRequested

[terrajobst]

Flag code that does if (token.IsCancellationRequested) throw new OperationCanceledException(); or if (token.IsCancellationRequested) throw new OperationCanceledException(token); and replace with token.ThrowIfCancellationRequested();.

Category: Style

[jeffhandley]

Estimates:

• Analyzer: Small
• Fixer: Small

[carlossanlop]

Suggested severity: Info

void MyMethod(CancellationToken c)
{
    // A) Simple check
    // Before
    if (c.IsCancellationRequested)
    {
        // Not sure if we want to cover other overloads as we cannot pass the parameters
        throw new OperationCanceledException();
    }

    // After
    c.ThrowIfCancellationRequested();

    // A) Negated check
    // Before
    if (!c.IsCancellationRequested)
    {
        DoSomething();
    }
    else
    {
        throw new OperationCanceledException();
    }

    // After
    c.ThrowIfCancellationRequested();
    DoSomething();


    // Excluded cases:

    // B) Multiple conditions in the if statement
    if (c.IsCancellationRequested && otherCondition)
    {
        throw new OperationCanceledException();
    }

    // C) There is extra logic in the if body
    if (c.IsCancellationRequested)
    {
        SomeOtherCode();
        throw new OperationCanceledException();
    }
}

[terrajobst]

Video

• Looks good
• We should only suggest this for OperationCanceledException, not TaskCanceledException because ThrowIfCancellationRequested throws the former.

[NewellClark]

I would like to be assigned to this.

[stephentoub]

This was implemented as CA2250. Thanks!