Visual Studio code metrics misreporting lines of code

Question

The code metrics analyser in Visual Studio, as well as the code metrics power tool, report the number of lines of code in the TestMethod method of the following code as 8.

At the most, I would expect it to report lines of code as 3.

[TestClass]
public class UnitTest1
{
    private void Test(out string str)
    {
        str = null;
    }

    [TestMethod]
    public void TestMethod()
    {
        var mock = new Mock<UnitTest1>();

        string str;
        mock.Verify(m => m.Test(out str));
    }
}

Can anyone explain why this is the case?

Further info

After a little more digging I've found that removing the out parameter from the Test method and updating the test code causes LOC to be reported as 2, which I believe is correct. The addition of out causes the jump, so it's not because of braces or attributes.

Decompiling the DLL with dotPeek reveals a fair amount of additional code generated because of the out parameter which could be considered 8 LOC, but removing the parameter and decompiling also reveals generated code, which could be considered 5 LOC, so it's not simply a matter of VS counting compiler generated code (which I don't believe it should do anyway).

Answer 1

There are several common definitions of 'Lines Of Code' (LOC). Each tries to bring some sense to what I think of as an almost meaningless metric. For example google of effective lines of code (eLOC).

I think that VS is including the attribute as part of the method declaration and is trying to give eLOC by counting statements and even braces. One possiblity is that 'm => m.Test(out str)' is being counted as a statement.

Consider this:

if (a > 1 &&
    b > 2)
{
   var result;
   result = GetAValue();
   return result;
}

and this:

if (a> 1 && b >2)
   return GetAValue();

One definition of LOC is to count the lines that have any code. This may even include braces. In such an extreme simplistic definition the count varies hugely on coding style.

eLOC tries to reduce or eliminate the influence of code style. For example, as may the case here, a declaration may be counted as a 'line'. Not justifying it, just explaining.

Consider this:

int varA = 0;
varA = GetAValue();

and this:

var varA = GetAValue();

Two lines or one?

It all comes down to what is the intent. If it is to measure how tall a monitor you need then perhaps use a simple LOC. If the intent is to measure complexity then perhaps counting code statements is better such as eLOC.

If you want to measure complexity then use a complexity metric like cyclomatic complexity. Don't worry about how VS is measuring LOC as, i think, it is a useless metric anyway.

Answer 2

With the tool NDepend we get a # Lines of Code (LoC) of 2 for TestMethod(). (Disclaimer I am one of the developers of this tool). I wrote an article about How do you count your number of Lines Of Code (LOC) ? that is shedding light on what is logical LoC, and how all .NET LoC counting tooling rely on the PDB sequence points technology.

My guess concerning this LoC value of 8 provided by VS metric, is that it includes the LoC of the method generated by the lambda expression + it includes the PDB sequences points related to open/ending braces (which NDepend doesn't). Also lot of gymnastic is done by the compiler to do what is called capturing the local variable str, but this shouldn't impact the #LoC that is inferred from the PDB sequence points.

Btw, I wrote 2 others related LoC articles:

• Why is it useful to count the number of Lines Of Code (LOC) ?
• Mythical man month : 10 lines per developer day

Answer 3

I was wondering about the Visual Studio line counting and why what I was seeing wasn't what was being reported. So I wrote a small C# console program to count pure lines of code and write the results to a CSV file (see below).

Open a new solution, copy and paste it into the Program.cs file, build the executable, and then you're ready to go. It's a .Net 3.5 application. Copy it into the topmost directory of your code base. Open a command window and run the executable. You get two prompts, first for name of the program/subsystem, and for any extra file types you want to analyze. It then writes the results to a CSV file in the current directory. Nice simple thing for your purposes or to hand to management.

Anyhoo, here it is, FWIW, and YMMV:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.IO;

namespace CodeMetricsConsole
{
    class Program
    {
        // Concept here is that the program has a list of file extensions to do line counts on; it
        // gets any extra extensions at startup from the user. Then it gets a list of files based on
        // each extension in the current directory and all subdirectories. Then it walks through 
        // each file line by line and will display counts for that file and for that file extension.
        // It writes that information to a CSV file in the current directory. It uses regular expressions
        // on each line of each file to figure out what it's looking at, and how to count it (i.e. is it
        // a line of code, a single or multi line comment, a multi-line string, or a whitespace line).
        // 
        static void Main(string[] args)
        {
            try
            {
                Console.WriteLine(); // spacing

                // prompt user for subsystem or application name
                String userInput_subSystemName;
                Console.Write("Enter the name of this application or subsystem (required): ");
                userInput_subSystemName = Console.ReadLine();

                if (userInput_subSystemName.Length == 0)
                {
                    Console.WriteLine("Application or subsystem name required, exiting.");
                    return;
                }

                Console.WriteLine(); // spacing

                // prompt user for additional types
                String userInput_additionalFileTypes;
                Console.WriteLine("Default extensions are asax, css, cs, js, aspx, ascx, master, txt, jsp, java, php, bas");
                Console.WriteLine("Enter a comma-separated list of additional file extensions (if any) you wish to analyze");
                Console.Write(" --> ");
                userInput_additionalFileTypes = Console.ReadLine();

                // tell user processing is starting
                Console.WriteLine();
                Console.WriteLine("Getting LOC counts...");
                Console.WriteLine();

                // the default file types to analyze - hashset to avoid duplicates if the user supplies extensions
                HashSet allowedExtensions = new HashSet { "asax", "css", "cs", "js", "aspx", "ascx", "master", "txt", "jsp", "java", "php", "bas" };

                // Add user-supplied types to allowedExtensions if any
                String[] additionalFileTypes;
                String[] separator = { "," };
                if (userInput_additionalFileTypes.Length > 0)
                {
                    // split string into array of additional file types
                    additionalFileTypes = userInput_additionalFileTypes.Split(separator, StringSplitOptions.RemoveEmptyEntries);

                    // walk through user-provided file types and append to default file types
                    foreach (String ext in additionalFileTypes)
                    {
                        try
                        {
                            allowedExtensions.Add(ext.Trim()); // remove spaces
                        }
                        catch (Exception e)
                        {
                            Console.WriteLine("Exception: " + e.Message);
                        }
                    }
                }

                // summary file to write to
                String summaryFile = userInput_subSystemName + "_Summary.csv";
                String path = Directory.GetCurrentDirectory();
                String pathAndFile = path + Path.DirectorySeparatorChar + summaryFile;

                // regexes for the different line possibilities
                Regex oneLineComment = new Regex(@"^\s*//"); // match whitespace to two slashes
                Regex startBlockComment = new Regex(@"^\s*/\*.*"); // match whitespace to /*
                Regex whiteSpaceOnly = new Regex(@"^\s*$"); // match whitespace only
                Regex code = new Regex(@"\S*"); // match anything but whitespace
                Regex endBlockComment = new Regex(@".*\*/"); // match anything and */ - only used after block comment detected
                Regex oneLineBlockComment = new Regex(@"^\s*/\*.*\*/.*"); // match whitespace to /* ... */
                Regex multiLineStringStart = new Regex("^[^\"]*@\".*"); // match @" - don't match "@"
                Regex multiLineStringEnd = new Regex("^.*\".*"); // match double quotes - only used after multi line string start detected
                Regex oneLineMLString = new Regex("^.*@\".*\""); // match @"..."
                Regex vbaComment = new Regex(@"^\s*'"); // match whitespace to single quote

                // Uncomment these two lines to test your regex with the function testRegex() below
                //new Program().testRegex(oneLineMLString);
                //return;

                FileStream fs = null;
                String line = null;
                int codeLineCount = 0;
                int commentLineCount = 0;
                int wsLineCount = 0;
                int multiLineStringCount = 0;
                int fileCodeLineCount = 0;
                int fileCommentLineCount = 0;
                int fileWsLineCount = 0;
                int fileMultiLineStringCount = 0;
                Boolean inBlockComment = false;
                Boolean inMultiLineString = false;

                try
                {
                    // write to summary CSV file, overwrite if exists, don't append
                    using (StreamWriter outFile = new StreamWriter(pathAndFile, false))
                    {
                        // outFile header
                        outFile.WriteLine("filename, codeLineCount, commentLineCount, wsLineCount, mlsLineCount");

                        // walk through files with specified extensions
                        foreach (String allowed_extension in allowedExtensions)
                        {
                            String extension = "*." + allowed_extension;

                            // reset accumulating values for extension
                            codeLineCount = 0;
                            commentLineCount = 0;
                            wsLineCount = 0;
                            multiLineStringCount = 0;

                            // Get all files in current directory and subdirectories with specified extension
                            String[] fileList = Directory.GetFiles(Directory.GetCurrentDirectory(), extension, SearchOption.AllDirectories);

                            // walk through all files of this type
                            for (int i = 0; i < fileList.Length; i++)
                            {
                                // reset values for this file
                                fileCodeLineCount = 0;
                                fileCommentLineCount = 0;
                                fileWsLineCount = 0;
                                fileMultiLineStringCount = 0;
                                inBlockComment = false;
                                inMultiLineString = false;

                                try
                                {
                                    // open file
                                    fs = new FileStream(fileList[i], FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
                                    using (TextReader tr = new StreamReader(fs))
                                    {
                                        // walk through lines in file
                                        while ((line = tr.ReadLine()) != null)
                                        {
                                            if (inBlockComment)
                                            {
                                                if (whiteSpaceOnly.IsMatch(line))
                                                {
                                                    fileWsLineCount++;
                                                }
                                                else
                                                {
                                                    fileCommentLineCount++;
                                                }

                                                if (endBlockComment.IsMatch(line)) inBlockComment = false;
                                            }
                                            else if (inMultiLineString)
                                            {
                                                fileMultiLineStringCount++;

                                                if (multiLineStringEnd.IsMatch(line)) inMultiLineString = false;
                                            }
                                            else
                                            {
                                                // not in a block comment or multi-line string
                                                if (oneLineComment.IsMatch(line))
                                                {
                                                    fileCommentLineCount++;
                                                }
                                                else if (oneLineBlockComment.IsMatch(line))
                                                {
                                                    fileCommentLineCount++;
                                                }
                                                else if ((startBlockComment.IsMatch(line)) && (!(oneLineBlockComment.IsMatch(line))))
                                                {
                                                    fileCommentLineCount++;
                                                    inBlockComment = true;
                                                }
                                                else if (whiteSpaceOnly.IsMatch(line))
                                                {
                                                    fileWsLineCount++;
                                                }
                                                else if (oneLineMLString.IsMatch(line))
                                                {
                                                    fileCodeLineCount++;
                                                }
                                                else if ((multiLineStringStart.IsMatch(line)) && (!(oneLineMLString.IsMatch(line))))
                                                {
                                                    fileCodeLineCount++;
                                                    inMultiLineString = true;
                                                }
                                                else if ((vbaComment.IsMatch(line)) && (allowed_extension.Equals("txt") || allowed_extension.Equals("bas"))
                                                {
                                                    fileCommentLineCount++;
                                                }
                                                else
                                                {
                                                    // none of the above, thus it is a code line
                                                    fileCodeLineCount++;
                                                }
                                            }
                                        } // while

                                        outFile.WriteLine(fileList[i] + ", " + fileCodeLineCount + ", " + fileCommentLineCount + ", " + fileWsLineCount + ", " + fileMultiLineStringCount);

                                        fs.Close();
                                        fs = null;

                                    } // using
                                }
                                finally
                                {
                                    if (fs != null) fs.Dispose();
                                }

                                // update accumulating values
                                codeLineCount = codeLineCount + fileCodeLineCount;
                                commentLineCount = commentLineCount + fileCommentLineCount;
                                wsLineCount = wsLineCount + fileWsLineCount;
                                multiLineStringCount = multiLineStringCount + fileMultiLineStringCount;

                            } // for (specific file)

                            outFile.WriteLine("Summary for: " + extension + ", " + codeLineCount + ", " + commentLineCount + ", " + wsLineCount + ", " + multiLineStringCount);

                        } // foreach (all files with specified extension)

                    } // using summary file streamwriter

                    Console.WriteLine("Analysis complete, file is: " + pathAndFile);

                } // try block
                catch (Exception e)
                {
                    Console.WriteLine("Error: " + e.Message);
                }
            }
            catch (Exception e2)
            {
                Console.WriteLine("Error: " + e2.Message);
            }

        } // main


        // local testing function for debugging purposes
        private void testRegex(Regex rx)
        {
            String test = "        asdfasd asdf @\"     adf ++--// /*\" ";

            if (rx.IsMatch(test))
            {
                Console.WriteLine(" -->| " + rx.ToString() + " | matched: " + test);
            }
            else
            {
                Console.WriteLine("No match");
            }
        }

    } // class
} // namespace

Here's how it works:

• the program has a set of the file extensions you want to analyze.
• It walks through each extension in the set, getting all files of that type in the current and all subdirectories.
• It selects each file, goes through each line of that file, compares each line to a regex to figure out what it's looking at, and increments the line count after it figures out what it's looking at.
• If a line isn't whitespace, a single or multi-line comment, or a multi-line string, it counts it as a line of code. It reports all the counts for each of those types of lines (code, comments, whitespace, multi-line strings) and writes them to a CSV file. No need to explain why Visual Studio did or did not count something as a line of code.

Yes, there are three loops embedded in each other (O(n-cubed) O_O ) but it's just a simple, standalone developer tool, and the biggest code base I've run it on was about 350K lines and it took like 10 seconds to run on a Core i7.

Edit: Just ran it on the Firefox 12 code base, about 4.3 million lines (3.3M code, 1M comments), about 21K files, with an AMD Phenom processor - took 7 minutes, watched the performance tab in Task Manager, no stress. FYI.

My attitude is if I wrote it to be part of an instruction fed to a compiler, it's a line of code and should be counted.

It can easily be customized to ignore or count whatever you want (brackets, namespaces, the includes at the top of the file, etc). Just add the regex, test it with the function that's right there below the regexes, then update the if statement with that regex.