CODEWITHSUNDEEP
c#code-analysis
Ray
Ray

Reputation: 8844

CA1806 DoNotIgnoreMethodResults raised erroneously?

Hence my following code:

[Conditional("DEBUG")]
internal static void WriteGLResult(string methodName, object result,
    params object[] args)
{
    string message = String.Format(CultureInfo.InvariantCulture, "{0}({1}) = {2}",
        methodName, String.Join(", ", args), result);
    Write(LogType.Information, Category.GLResult, 2, message);
}

I'm clearly assigning the String.Format() result to the variable message. I'm also passing that instance to the Write method afterwards. Yet CA1806 is raised:

Do not ignore method results

'Log.WriteGLResult(string, object, params object[])' calls 'string.Format(IFormatProvider, string, params object[])' but does not use the new string instance that the method returns. Pass the instance as an argument to another method, assign the instance to a variable, or remove the call if it is unnecessary.`

In the called Write method, I'm also using the string, there named format, as it's used like this:

[Conditional("DEBUG")]
private static void Write(LogType logType, Category category, int stackTraceFrameSkips,
    string format, params object[] args)
{
    // ...
    string message = String.Format(CultureInfo.InvariantCulture, format, args);
    // ...
}

I don't know how to fix this warning. And I doubt CA raises this erroneously.

Can you help me?

Upvotes: 0

Views: 615

Answers (1)

user743382
user743382

Reputation:

Expanding from the comments:

Since Write is defined as

[Conditional("DEBUG")]
private static void Write(LogType logType, Category category, int stackTraceFrameSkips,
    string format, params object[] args)

that means the calls to Write will be completely removed when the DEBUG symbol is not defined. The code analysis runs later, and by that time it can determine (correctly) that message is never used.

For something that neither warns in debug nor in release mode, you might want to move the call to String.Format directly into the method arguments:

Write(LogType.Information, Category.GLResult, 2,
    String.Format(CultureInfo.InvariantCulture, "{0}({1}) = {2}",
    methodName, String.Join(", ", args), result));

This should make sure that String.Format is only called when Write will be called.

Upvotes: 1

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