Checking variable before use

[Jim]

Hello, Again.

I am working on an exception to ensure that developers check incoming variables to a method before they use them.  I'm having problems when they use a method like "String.IsNullOrEmpty(variable)".  Here is the example code...

VB.NET

Public Sub test(ByVal str As String, ByVal logLine As String)

    Dim Y as string = str

    If String.IsNullOrEmpty(logLine) Then
        Throw New Exception("LogConsoleLogInfo: empty string logLine")
    End If

    Dim X as String = logLine

End Sub

C#

public void test(String str, String logLine)
{

    str Y = str;

    If (String.IsNullOrEmpty(logLine) { Throw New Exception("LogConsoleLogInfo: empty string Logline");

    str X = logLine;

}

I would completely expect "str" to be underlined in my exception, but since they checked "logLine" with String.IsNullOrEmpty, it shouldn't be underlined.  I either get both or neither with my existing code. 

Any help would be greatly appreciated!

Thanks,

Jim Evans
Application Architect, eMASON, Inc.

[Zdravko]

Hi Jim,

 Thanks for contacting us.
Can you provide us your source code so we could examine it?
Thank you.

Greetings,
Zdravko
the Telerik team

[Jim]

Here is the code.  There are no external voids called by this code...  (Note:  I'd attach the code file in ZIP format but it won't let me.)

foreach (IMethodDeclaration md in fileModel.All<IMethodDeclaration>().Where(m => (m.Parameters.Any() &&   

                                                                                          !m.EnclosingClass.IsInterface && !m.EnclosingClass.IsStruct &&                                                                        

                                                                                          !m.Identifier.Name.ToUpper().Contains("VERIF") &&

                                                                                          !m.Identifier.Name.ToUpper().Contains("VALIDAT"))))

        {

            // An IParameter is NOT the param, but the entire parameter clause.  eg "byVal ex as System.Exception" instead of "ex"

            foreach (IParameter oParam in md.Parameters.Parameters)

            {

                // If our param isn't null, is a complex type, and is NOT an enumeration, we want to evaluate it.

                if (oParam != null &&

                    !oParam.Type.IsPrimitiveType &&

                    !oParam.Type.IsEnumType &&

                    !oParam.Type.Is("System.EventArgs"))

                {

                    var allAccesses = oParam.AllAccesses();

                    var firstAccess = allAccesses.First();

                    var enclosingStatementExpression = firstAccess.EnclosingStatement().As<IExpressionStatement>().Expression;

                    if (!enclosingStatementExpression.Is<IMethodInvocation>())

                    {

                        oParam.AddCodeMarker(Constants.EM108WarningExampleID, this, Constants.EM108FixText);

                    }

                    else

                    {

                        var methodInvocation = enclosingStatementExpression.As<IMethodInvocation>();

                        if (!methodInvocation.Language.AreNamesEqual(methodInvocation.Identifier.Name, "Verify") && !methodInvocation.Language.AreNamesEqual(methodInvocation.Identifier.Name, "ASSERT"))

                        {

                            oParam.AddCodeMarker(Constants.EM108WarningExampleID, this, Constants.EM108FixText);

                        }

                    }

                }

            }

        }



[Zdravko]

Hi Jim,

 Thanks for contacting us.
Here I will post the solution:

protected override void AddCodeMarkers(FileModel fileModel)

        {

            // you can use fileModel.All<T> to iterate over the construct you are interested in

            // you might also use LINQ queries

            foreach (IMethodDeclaration md in fileModel.All<IMethodDeclaration>().Where(m => (m.Parameters.Any() &&

                                                                                              !m.EnclosingClass.IsInterface && !m.EnclosingClass.IsStruct &&

                                                                                              !m.Identifier.Name.ToUpper().Contains("VERIF") &&

                                                                                              !m.Identifier.Name.ToUpper().Contains("VALIDAT"))))

            {

                // An IParameter is NOT the param, but the entire parameter clause.  eg "byVal ex as System.Exception" instead of "ex"

                foreach (IParameter oParam in md.Parameters.Parameters)

                {

                    // If our param isn't null, is a complex type, and is NOT an enumeration, we want to evaluate it.

                    if (oParam != null &&

                        !oParam.Type.IsPrimitiveType &&

                        !oParam.Type.IsEnumType &&

                        !oParam.Type.Is("System.EventArgs"))

                    {

                        var firstAccess = oParam.AllAccesses().First();

                        if (firstAccess.Exists)

                        {

                            var enclosingStatementExpression = firstAccess.EnclosingStatement();

 

                            if (enclosingStatementExpression.Is<IIfStatement>())

                            {

                                var ifStatement = enclosingStatementExpression.As<IIfStatement>();

                                if (!IsMethodInvocationWithName(ifStatement.Condition, "IsNullOrEmpty") &&

                                    !ifStatement.Condition.ChildExpressions.Where(x => IsMethodInvocationWithName(x, "IsNullOrEmpty")).Exist())

                                {

                                    oParam.AddCodeMarker(Constants.EM108WarningExampleID, this, Constants.EM108FixText);

                                }

                            }

                            else if (enclosingStatementExpression.Is<IMethodInvocation>())

                            {

                                var methodInv = enclosingStatementExpression.As<IMethodInvocation>();

                                if (!methodInv.Language.AreNamesEqual(methodInv.Identifier.Name, "Verify")

                                    && !methodInv.Language.AreNamesEqual(methodInv.Identifier.Name, "ASSERT"))

                                {

                                    oParam.AddCodeMarker(Constants.EM108WarningExampleID, this, Constants.EM108FixText);

                                }

                            }

                            else

                            {

                                oParam.AddCodeMarker(Constants.EM108WarningExampleID, this, Constants.EM108FixText);

                            }

                        }

                    }

                }

            }

        }

private bool IsMethodInvocationWithName(IExpression expression, string name)
{
return expression.Is<IMethodInvocation>() && expression.Language.AreNamesEqual(expression.As<IMethodInvocation>().Identifier.Name, name);
}


If you like to expand the check for IIfStatement just copy the 'if' and change the string and for the IMethodInvocation just add additional conditions.
Thanks.

I hope it helps.

All the best,
Zdravko
the Telerik team