Showing posts with label programming. Show all posts
Showing posts with label programming. Show all posts

20/04/2017

How I removed 50% of the code

Home

Title: Azuleyo tiles somewhere in Portugal, Source: own resources, Authors: Agnieszka and Michał Komorowscy


My last 2 posts were about problems with using Roslyn. Nonetheless, even if I sometime hate it, I'm still using it so the time has come to show some practical example of using Roslyn. Recently, I've been working on the task that can be summed up as: Take this ugly code and do something with it. i.e. more or less the refactoring task.

Now I'll give you some intuition of what I have to deal with. The code that I have to refactor was generated automatically based on XML schema. These were actually DTO classes used to communicate with the external service. Here are some statistics:
  • 28.7 thousands lines of code in 23 files.
  • 2200 classes and 920 enums.
  • Many classes and enums seems to me identical or very similar.

10/04/2017

Why I hate Roslyn even more

Home



In my previous post I wrote about my problem with "empty" projects and Roslyn. The symptom was that in some cases according to Roslyn my C# projects didn't contain any files. For quite a long time, I haven't been able to find a solution. Especially because I couldn't reproduce problem on my local machine. Fortunately, today I noticed exactly the same problem on another computer.

29/03/2017

Why I hate Roslyn

Home



The more I work with Roslyn the more I appreciate the possibilities it gives and the more I hate it. And I hate it for the same thing as many other projects I worked with in the past. What is it? Well, I like when a system fails fast, fails loudly and fails in the clear way. Unfortunately, Roslyn can do something completely different what sometimes makes working with it the pain in ass. I'll give you some examples.

Issue 1 - Problem with "empty" projects

Here is the code that shows how I usually process documents/files for a given project. It's pretty easy.
var workspace = MSBuildWorkspace.Create();

var sln = await workspace.OpenSolutionAsync(path);
     
foreach (var projectId in sln.ProjectIds)
{
   var project = sln.GetProject(projectId);

   foreach (var documentId in project.DocumentIds)
   {
      // Process a document
   }
}
It works quite well but only on my machine :) On 2 other machines I'm observing problems. In general I have an example solution with 2 test projects. One is WPF application and the another is WebAPI.

The problem is that on some machines I can only read and analyze WPF application. If I try to do exactly the same thing with WebAPI application, then the project loaded by Roslyn is empty i.e. contains no documents (DocumentIds property is empty)! I've already tried to load this project in a different way but without success.

To be honest currently I'm stuck and I have no idea what is wrong here. Any suggestions?

Issue 2 - the semantic analysis does not work

With Roslyn we can perfrom the syntax analysis and the semantic analysis of the code. The syntax analysis, with a syntaxt tree, allows you to only see a structure of a program. The semantic analysis is more powerfull and allows you to understand more. For example, having a code like that:

SomeClass x;

With the semantic analysis you can check that SomeClass is defined within SomeNamespace and has X members (methods, properties). For example, here we have a code showing how to use the semantic analysis to check what interfaces are implemented by a given class at any level of the inheritance.
var compilation = await project.GetCompilationAsync();

foreach (var documentId in project.DocumentIds)
{
   var document = project.GetDocument(documentId);

   // Get a syntax tree
   var tree = await document.GetSyntaxTreeAsync(); 

   // Get a root of the syntax tree
   var root = await tree.GetRootAsync(); 
   
   // Find a node of the syntaxt tree for a first class in a file/document
   var classNode= root.DescendantNodes().OfType<ClassDeclarationSyntax>().FirstOrDefault(); 

   if(classNode== null) continue;

   // Get a semantic model for the syntax tree
   var semanticModel = compilation.GetSemanticModel(tree); 

   // Use the semantic model to get symbol info for the found class node
   var symbol = semanticModel.GetDeclaredSymbol(classNode); 

   // Check what inerfaces are implemnted by the class at any level
   foreach(var @interface in symbol.AllInterfaces)  
   {
      // ...
   }
}
If you run this code as it is, it again will not throw any exceptions. However, you'll noticed that any found class doesn't implement any interface according to Roslyn. Where is the problem this time?

It's quite obious if you know that. To perform the semantic analysis Roslyn needs to analyse assemblies used by the project. However, it's now enough to compile the project. You have to explicitly register all required assemblies. I do it in the easy way. I simply register all assemblies found in the output folder.
var compilation = await project.GetCompilationAsync();

// Let's register mscorlib
compilation = compilation.AddReferences(MetadataReference.CreateFromFile(typeof(object).Assembly.Location));

if (Directory.Exists("PATH TO OUTPUT DIRECTORY"))
{
   var files = Directory.GetFiles(directory, "*.dll").ToList(); // You can also look for *.exe files

   foreach (var f in files)
      compilation = compilation.AddReferences(MetadataReference.CreateFromFile(f));
}
And again if the semantic analysis can not be performed without that why no exception is thrown?

Issue 3 - Problem with reading projects/solutions

This one I've already described in more details in the post about Roslyn and unit tests. The problem was that:
  • MSBuildWorkspace.OpenSolutionAsync method was returning an empty solution if a particular assembly was missing (not fast, not loud)
  • MSBuildWorkspace.OpenSolutionAsync method was returning the error The language 'C#' is not supported (not in the clear way).
This particular assembly was Microsoft.CodeAnalysis.CSharp.Workspaces.dll so wouldn't it be easier to just throw an xception saying that it is missing. Or at least saying that it was not possible to find assembly responsible for reading C# projects and solutions.


Remember failing fast, loudly and in the clear way does not cost much but can save a lot of time.


*The picture at the beginning of the post comes from own resources and shows cliffs near Cabo da Roca - the westernmost extent of mainland Portugal.

24/03/2017

Report from the battlefield #10 - fuck-up with AutoMapper

Home



Have you ever heard or used AutoMapper? What a question, of course you have. And in the very unlikely scenario that you haven't, it's the object to object mapper that allows you to map probably everything. In short no more manual, boring, tedious, error-prone mapping.

However, the great power comes with great responsibility. In the recent time, I had an occasion to fix 2 difficult to track bugs related to improper usage of AutoMapper. Both issues were related to the feature of AutoMapper which according to me is almost useless and at least should be disabled by default. Let's look at the following 2 classes and testing code:
public class SomeSourceClass
{
   public Guid Id { get; set; }
   public string IdAsString => Id.ToString();
   public string Value { get; set; }
}

public class SomeDestinationClass
{
   public Guid Id { get; set; }
   public string IdAsString => Id.ToString();
   public string Value { get; set; }
}

class Program
{ 
   static void Main()
   {
      Mapper.Initialize(config => config.CreateMap<SomeSourceClass,SomeDestinationClass>>());
      
      var src = new SomeSourceClass { Id = Guid.NewGuid(), Value = "Hello" };
      var dest = Mapper.Map<SomeDestinationClass>(src);

      Console.WriteLine($"Id = {dest.Id}");
      Console.WriteLine($"IdAsString = {dest.IdAsString}");
      Console.WriteLine($"Value = {dest.Value}");
   }
}
This works as a charm. If you run this example, you should see output like that:

Id = a2648b9e-60be-4fcc-9968-12a20448daf4
IdAsString = a2648b9e-60be-4fcc-9968-12a20448daf4
Value = Hello

Now, let's introduce interfaces that will be implemented by SomeSourceClass and SomeDestinationClass:
public interface ISomeSourceInterface
{
   Guid Id { get; set; }
   string IdAsString { get; }
   string Value { get; set; }
}

public interface ISomeDestinationInterface
{
   Guid Id { get; set; }
   string IdAsString { get; }
   string Value { get; set; }
}

public class SomeSourceClass: ISomeSourceInterface { /*... */}

public class SomeDestinationClass : ISomeDestinationInterface { /*... */}
We also want to support mappings from ISomeSourceInterface to ISomeDestinationInterface so we need to configure AutoMapper accordingly. Otherwise the mapper will throw an exception.
Mapper.Initialize(config =>
   {
      config.CreateMap<SomeSourceClass, SomeDestinationClass>();
      config.CreateMap<ISomeSourceInterface, ISomeDestinationInterface>();
   });

var src = new SomeSourceClass { Id = Guid.NewGuid(), Value = "Hello" };
var dest = Mapper.Map<ISomeDestinationInterface>(src);

Console.WriteLine($"Id = {dest.Id}");
Console.WriteLine($"IdAsString = {dest.IdAsString}");
Console.WriteLine($"Value = {dest.Value}");
If you run this code, it'll seemingly work as the charm. However, there is a BIG PROBLEM here. Let's examine more carefully what was written to the console. The result will look as follows:

Id = a2648b9e-60be-4fcc-9968-12a20448daf4
IdAsString =
Value = Hello

Do you see a problem? The readonly property IdAsString is empty. It seems crazy because IdAsString property only returns the value of Id property which is set. How is it possible?

And here we come the feature of AutoMapper which according to be should be disabled by default i.e. automatic proxy generation. When AutoMapper tries to map ISomeSourceInterface to ISomeDestinationInterface it doesn't know which implementation of ISomeDestinationInterface should be used. Well, actually no implementation may even exists, so it generates one. If we check the type of dest property we'll see something like:

Proxy<ConsoleApplication1.ISomeDestinationInterface_ConsoleApplication1_Version=1.0.0.0_Culture=neutral_PublicKeyToken=null>.

Initially this function may look as something extremely useful. But it's the Evil at least because of the following reasons:
  • As in the example, the mapping succeeds but the result object contains wrong data. Then this object may be used to create other objects... This can lead to really difficult to detect bugs.
  • If a destination interface defines some methods, a proxy will be generated, but the mapping will fail due to System.TypeLoadException.
  • It shouldn't be needed in the well written code. However, if you try to cast the result of the mapping to the class, then System.InvalidCastException exception will be thrown.
The ideal solution would be to disable this feature. However, I don't know how :( The workaround is to explicitly tell AutoMapper not to generate proxies. To do that we need to use As method and specify which concrete type should be created instead of a proxy.

The final configuration looks as follows. It's also worth mentioning that in this case we actually don't need to define mapping from SomeSourceClass to SomeDestinationClass. AutoMapper is clever enough to figure out that these classes implements interfaces.
Mapper.Initialize(
   config =>
   {
      config.CreateMap<ISomeSourceInterface, ISomeDestinationInterface>().As<SomeDestinationClass>();
   });


AutoMapper proxy generation feature is the Evil.


*The picture at the beginning of the post comes from own resources and shows Okonomiyaki that we ate in Hiroshima. One of the best food we've ever eaten.

08/03/2017

Roslyn and unit tests suck

Home


Title: Imperial Gardens in Tokyo, Source: own resources, Authors: Agnieszka and Michał Komorowscy

I'm working on the project where I have an opportunity to use Roslyn compiler as a service. It is very good :) However yesterday it took me more than 2 hours to write working unit tests (based on MSTest) for my code! Here are some tips that may save your time.

Let's start with the simle thing. When I run unit tests for the first time the following exception was thrown:

System.IO.FileNotFoundException: Could not load file or assembly 'System.Runtime...' or one of its dependencies.

To fix this problem I simply installed the following packages via Nuget:
  • Microsoft.CodeAnalysis.CSharp
  • Microsoft.CodeAnalysis.CSharp.Workspaces
Later it was harder. In my code I use MSBuildWorkspace.OpenSolutionAsync and MSBuildWorkspace.OpenProjectAsync methods to respectively open the entire solution or a single project for further processing.

The next issue was that the first method called from within a unit test was returning an empty solution i.e. without any projects. Whereas the second one was throwing an exception with the message: The language 'C#' is not supported. What was strange these problems occurred only in unit tests! To investigate a problem I opened Exception settings window in Visual Studio and selected a check box next to Common Language Runtime Exceptions. Then, I run the unit tests one more time and Visual Studio quickly reported the exception in the line with MSBuildWorkspace.OpenProjectAsync:

System.IO.FileNotFoundException: Could not load file or assembly 'Microsoft.CodeAnalysis.CSharp.Workspaces...' or one of its dependencies.

It was even more strange because my unit test project was actually referencing Microsoft.CodeAnalysis.CSharp.Workspaces.dll! To double check, I went to the unit tests working directory. It is a folder called TestResults which by default is located in the solution directory. To my surprised this dll was missing!

Fortunately, I reminded myself the similar situation from the past. The problem is that MSTest doesn't copy all assemblies to the output directory by default. As far as I know it tries to figure out which assemblies are really needed by the code being tested. Here, I'm not sure but Microsoft.CodeAnalysis.CSharp.Workspaces.dll may be cumbersome because it is not directly referenced by other Roslyn assemblies. Instead, it is probably loaded dynamically when needed.

To fix a problem you can use the simple hack i.e. use directly any code from Microsoft.CodeAnalysis.CSharp.Workspaces.dll in your unit tests in the following way:

[ClassInitialize]
public static void ClassInitialize(TestContext ctx)
{
   var t = typeof(Microsoft.CodeAnalysis.CSharp.Formatting.LabelPositionOptions);
}

Why did I use LabelPositionOptions? Because majority of types defined in aforementioned assembly is internal and this one was the first public type I found :)

13/02/2017

C++ for C# developers - automatic garbage collection

Home


Title: Sushi on the fish market in Tokyo, Source: own resources, Authors: Agnieszka and Michał Komorowscy

In my previous post I wrote that C++ doesn't have the automatic garbage collection. However, it's not entirely true. Let's think about it more carefully. To start, look at the following method in C#. It simply creates an instance of MyObject class.
public void Fun() 
{
   var x = new MyObject();
   //...
}
When this object will be collected by GC? When it is needed but not sooner than the execution of Fun method is finished. Can we do the same thing in C++? Of course yes, here is an example:
void fun() {
   MyObject x;
   //...
}
If you are not familiar with C++ you may say that I only declared the variable x in this example and that I didn't create any object. Well, in C++ the following 3 commands are equivalent:

MyObject x;
MyObject x();
MyObject x = MyObject();

Personally, I still cannot used to that ;) But let's return to C++ and ask the similar question as for C#. When a destructor will be called for created instance of MyObject? The answer is easy - when the execution of fun method is over. Or in other words when an object goes out of scope. It's worth nothing that this behaviour is called the automatic storage duration. Usually it is implemented by using stack however it's not the rule. Now, let's consider this code in C++:
void fun() {
   MyObject* x = new MyObject();
   //...
}
It looks almost the same like in C#. However, this time we're creating an object dynamically with new keyword. And this kind of objects won't be removed automatically from the memory, even if the execution of fun is over. This is also known as the dynamic storage duration. How to release this kind of objects?

In the past a C++ developer had to use delete keyword to do so. I did the same in the code from my post about virtual destructors. However, since C++ 11 we can use something else i.e. the explicit automatic garbage collection. More precisely I'm talking about smart pointers. Here is the rewritten version of Node class:

class Node {
 public:
  static int _count;
  
  Node(int i) : _value(i) { Node::_count++; }
  ~Node() {
    std::cout << "~Node " << _value;
    _count--;
  }
  
  int _value;

  std::unique_ptr<Node> _left = nullptr;
  std::unique_ptr<Node> _right = nullptr;
};

int Node::_count = 0;
In this code I defined ~Node destructor only for its side effects i.e. to decrease a counter. I didn't use delete in this code at all. Instead I wrapped pointers with std::unique_ptr. It works in this way that it releases the pointer when it goes out of scope. Nothing more nothing less. But thanks to that we don't have to remember about delete. Almost like in C#. Here is the testing code:
int main()
{
    Node* root = new Node(1);
    root->_left = std::unique_ptr<Node>(new Node(2));
    root->_right = std::unique_ptr<Node>(new Node(3));

    std::cout << " Existing nodes: " <<  Node::_count;
    delete root;
    std::cout << " Existing nodes: " <<  Node::_count;
}
I didn't wrap root in a smart pointer because I wanted to explicitly use delete and verify the final number of nodes. Easy, isn't it?

At the end it's worth mentioning that there are also different types of smart pointers. shared_ptr should be used when the same pointer can have many owners. Whereas std::weak_ptr represents the same concept as C# WeakReference class. Last but not least, except the automatic storage duration and the dynamic storage duration we also have the static storage duration and the thread storage duration. The former is used to store static variables which are release at the end of program (pretty the same as in C#) and the latter to store variables that will survive until the end of a thread (in C# we can use TheradLocalStorage for the similar effect). More reading can be found here.

06/02/2017

C++ for C# developers - virtual destructors

Home


Title: Tokio, Source: own resources, Authors: Agnieszka and Michał Komorowscy

In C# it's simple, we use destructors a.k.a. finalizers almost never. The only one case when they are inevitable is the implementation of Disposable pattern. In C++ the situation is different because we don't have the automatic garbage collection. It means that if we create a new object with new keyword we have to destroy it later by using delete keyword. And if the object being deleted contains pointers to other objects created dynamically, they also need to be deleted. It's where destructors come to game. Here is an example with a class Node which models a binary tree. It's simplified and it is why all fields are public, don't do it in the production! Node::_count is a static field that I'm using to count created objects.
#include <stdexcept>
#include <iostream>

class Node {
 public:
  Node(int i) : _value(i) { Node::_count++; }
  
  ~Node() {
    std::cout << " ~Node " << _value <<;
    
    if(_left != nullptr) delete _left;
    if(_right != nullptr) delete _right;
    
    _count--;
  }

  static int _count;
 
  int _value;
  
  Node* _left = nullptr;
  Node* _right = nullptr;
};

int Node::_count = 0;
Here is a testing code. If you run it you should see the result as follows: Existing nodes: 3 ~Node 1 ~Node 2 ~Node 3 Existing nodes: 0. We can see that all nodes have been deleted and that a destructor was executed 3 times.
int main()
{
    Node* root = new Node(1);
    root->_left = new Node(2);
    root->_right = new Node(3);

    std::cout << " Existing nodes: " << Node::_count;
    delete root;
    std::cout << " Existing nodes: " << Node::_count;
}
Now let's derived a new class from Node in the following way:
class DerivedNode : public Node {
 public:
  DerivedNode(int i) : Node(i) {
  }
  ~DerivedNode() {
    std::cout << " ~DerivedNode " << _value;
  }
};
And modify a testing code a little bit in order to use our new class:
int main()
{
    Node* root = new DerivedNode(1);
    root->_left = new DerivedNode(2);
    root->_right = new DerivedNode(3);

    std::cout << " Existing nodes: " << Node::_count;
    delete root;
    std::cout << " Existing nodes: " << Node::_count;
}
The expectation is that ~DerivedNode destructor should be called together with the base class destructor ~Node. However, if you run the above code you'll notice see that it's not true i.e. you'll see the same result as earlier. To explain what's going look at the C# code below and answer the following question: Why I see "I'm A" if I created an instance of class B
public class A
{
   public void Fun() { Console.WriteLine("I'm A"); }
}

public class B: A
{
   public void Fun() { Console.WriteLine("I'm  B"); }
}

A a = new B();
a.Fun();
I hope that it's not a difficult question. The answer is of course because Fun is not a virtual method. In C++ we have the same situation. Now you may say "Wait a minute, but we're talking about destructors not methods". Ya, but destructors are actually a special kind of methods. The fix is simple we just need to use a concept completely unknown in C# i.e. a virtual destructor.
virtual ~Node() {
  ...
}
This time the test code will give the following result Existing nodes: 3 ~DerivedNode 1 ~Node 1 ~DerivedNode 2 ~Node 2 ~DerivedNode 3 ~Node 3 Existing nodes: 0 .

30/01/2017

C++ for C# developers - var and foreach

Home


Title: A-Bomb dome in Hiroshima, Source: own resources, Authors: Agnieszka and Michał Komorowscy

When I returned to programming in C++ after years of using C# a few things were especially painful. Today I'll wrote about 2 at the top of the list. The first one was a need to explicitly declare types of local variables. For example:
std::vector< std::string > v = someMethod();
std::map< std::string, std::map<std::string, std::string> > m = someMethod2();
It looks terrible and is simply cumbersome. However, as you may noticed I used the past tense. It turned out that it's not needed any more. Glory and honor to C++11!!! Now, I can write something like this.
auto v = someMethod();
auto m = someMethod2();
The second problem was the lack of foreach operator. For example let's write a code that iterates through a map from the example above:
typedef std::map<std::string, std::map<std::string, std::string>>::iterator outer_iterator;
typedef std::map<std::string, std::string>::iterator inner_iterator;
    
for(outer_iterator it1 = m.begin(); it1 != m.end(); it1++) {
   for(inner_iterator it2 = it1->second.begin(); it2 != it1->second.end(); it2++) {
      std::cout<< it1->first << " " << it2->first << " " << it2->second << std::endl;
   }
}
Again it looks terrible and is cumbersome. All this begin(), end(), typedef are horrible. We can fix it a little bit if we use auto keyword:
for(auto it1 = m.begin(); it1 != m.end(); it1++) {
 for(auto it2 = it1->second.begin(); it2 != it1->second.end(); it2++) {
  std::cout<< it1->first << " " << it2->first << " " << it2->second << std::endl;
 }
}
But even the better result we will achieve if we use a new for loop syntax:
for(auto it1 : m) {
   for(auto it2 : it1.second) {
      std::cout<< it1.first << " " << it2.first << " " << it2.second << std::endl;
   }
}
The difference is striking! It's so much readable and easier to write and uderstand.

23/01/2017

C++ for C# developers - code like in Google

Home


Title: Elephant Retirement Camp in the vicinity of Chiang Mai, Source: own resources, Authors: Agnieszka and Michał Komorowscy

In the post Nuget in C++ rulez I wrote that I returned to programming in C++. It is like a new world for me but it's better and better. I'm even reminding myself things that I learned many years ago so it's not bad with me ;) Recently, I've discovered a C++ alternative for .NET StyleCop. StyleCop is a tool that analyses C# code in order to check if it is consistent with given rules and good practices. What is obvious there is a similar thing for C++ I'm talking about a tool called CppLint that was created by Google. It's written in Python and is fairly easy in use. However, please note that CodeLint requires the old Python 2.7. I tried and it won't work with Python 3.5.

When I run CppLint on my code it turned out that my habits from C# don't fit to C++ world according to Google. Here is an example of Hello Word written in C++ but in C# style.
#include <iostream>

namespace sample 
{
    class HelloWorld
    {
        public:
            void Fun()
            {
                std::cout << "Hello World Everyone!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!" << std::endl;
            }
    };
}

int main()
{
  sample::HelloWorld hw = sample::HelloWorld();
  hw.Fun();
  
  return 0;
}
If we verify this code, we will get the following errors:
a.cpp:0:  No copyright message found.  You should have a line: "Copyright [year] <Copyright Owner>"  [legal/copyright] [5]
a.cpp:3:  Line ends in whitespace.  Consider deleting these extra spaces.  [whitespace/end_of_line] [4]
a.cpp:4:  { should almost always be at the end of the previous line  [whitespace/braces] [4]
a.cpp:5:  Do not indent within a namespace  [runtime/indentation_namespace] [4]
a.cpp:6:  { should almost always be at the end of the previous line  [whitespace/braces] [4]
a.cpp:7:  public: should be indented +1 space inside class HelloWorld  [whitespace/indent] [3]
a.cpp:9:  { should almost always be at the end of the previous line  [whitespace/braces] [4]
a.cpp:10:  Lines should be <= 80 characters long  [whitespace/line_length] [2]
a.cpp:13:  Namespace should be terminated with "// namespace sample"  [readability/namespace] [5]
a.cpp:16:  { should almost always be at the end of the previous line  [whitespace/braces] [4]
a.cpp:19:  Line ends in whitespace.  Consider deleting these extra spaces.  [whitespace/end_of_line] [4]
a.cpp:21:  Could not find a newline character at the end of the file.  [whitespace/ending_newline] [5]
At the beginning of each line we have the line number where an error was detected. The number in square brackets at the end of each line informs you how confident CppLint is about each error i.e. 1 - it may be a false positive, 5 - extremely confident. In order to fix all these problems I did the following things:
  • Added Copyright 2016 Michał Komorowski.
  • Removed whitespaces at the end of lines.
  • Added a new line at the end of file.
  • Added a comment // namespace sample
  • Move curly braces. This one I don't like the most.
  • Break a too long line. It's also a little bit strange to me. 80 doesn't seem to be a lot. However, shorter lines makes working with multiple windows easier (see also this answer).
Then I run a tool again and I got some new errors:
a.cpp:6:  Do not indent within a namespace  [runtime/indentation_namespace] [4]
a.cpp:7:  public: should be indented +1 space inside class HelloWorld  [whitespace/indent] [3]
I also fixed them and the final version of Hello Worlds compliant with Google rules looks as follows: Here is the correct version:
// Copyright 2016 Michal Komorowski

#include <iostream>

namespace sample {
class HelloWorld {
 public:
  void Fun() {
    std::cout
      << "Hello World Everyone!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
      << std::endl;
  }
};
}  // namespace sample

int main() {
  sample::HelloWorld hw = sample::HelloWorld();
  hw.Fun();
  return 0;
}

It's worth adding that CppLint has many configuration options for example you can disable some rules if you don't agree with them or change the maximum allowed length of a line (default is 80). Options can be also read from the configuration file CPPLINT.cfg.

26/12/2016

Migration to Nuget V3

Home


Source: own resources, Authors: Agnieszka and Michał Komorowscy

Sometime ago I wrote a post about My struggels with GitHub, Subtrees and Nuget and Joseph suggested me another solution of my problem in the comments i.e. to switch to Nuget V3. A few days ago I finally found time to give it a try. I started by reading this tutorial/post written by Oren Novotny. It's really a good source of knowledge so I'll not describe the whole process again. However, I encountered 3 problems that weren't described and I'll briefly write about them.

Project.json vs Project.config

A new Nuget uses project.json file instead of the old project.config so I started with adding this new file to all projects. Then I moved packages from the old files to the new ones. In the next step I reloaded all the projects just to be sure that VS will see changes. After that I built the solution to see if it works and it worked. Finally, I made a commit and pushed my changes. And here comes a problem. In a few minutes I got an e-mail from my Azure (hosted) build controller that a build has just failed.

§ Error: C:\a\_tasks\NuGetInstaller_333b11bd-d341-40d9-afcf-b32d5ce6f23b\0.2.24\node_modules\nuget-task-common\NuGet\3.3.0\NuGet.exe failed with return code: 1
§ Packages failed to install

The source of a problem was apparently a conflict between project.config and project.json so I just removed the former from the projects.

Naming problem

It is not everything. The next problem looked in the following way:

Failed to resolve conflicts for .NETFramework,Version=v4.6 (win).
Unable to satisfy conflicting requests for 'MVVMLight': project/MVVMLight (>= 1.0.0) (via project/MVVMLight 1.0.0)
Unable to satisfy conflicting requests for 'CommonServiceLocator': CommonServiceLocator (>= 1.3.0) (via project/MVVMLight 1.0.0)
Unable to satisfy conflicting requests for 'MvvmLight': MvvmLight (>= 5.1.1) (via project/MVVMLight 1.0.0)...

This time the fix was also easy. Nuget V3 doesn't like if the projects in the solution have exactly the same names as packages! In my solution I had MVVMLight project which is my playground for MVVMLight package. I renamed in to MVVMLightTest.

Last but not the least

After migration to Nuget V3 I had to deal with one more problem and again I didn't observe it locally but only when building on Azure (hosted) build controller. In the build log I found the following error:

The OutputPath property is not set for project 'LanguageTrainer.csproj'. Please check to make sure that you have specified a valid combination of Configuration and Platform for this project. Configuration='Debug' Platform='x86'.

And it turned out that in some csproj files I had the following condition:

<Platform Condition=" '$(Platform)' == '' ">x86</Platform>

It says that if the platform is not specified for a given build then use x86. At the same time these csproj didn't contain configuration, including the problematic OutputPath, for x86. To fix a problem I simply changed x86 to AnyCPU.

12/12/2016

Did you know that about HTTP?

Home


Titile: Chapel of the Emerald Buddha in Bangkok, Source: own resources, Authors: Agnieszka and Michał Komorowscy

Recently, when answering a question on stackoverflow.com, I've learned an interesting thing about HTTP protocol. Actually currently it seems to be obvious to me ;) What I'm talking about? Well, initially I thought that if you send GET HTTP request in order to download a specific URL, then in a response you will get an entire page/file. In other words I thought that it's not possible to read the specific part of a page/file. However, it turned out that it's quite easy.

28/11/2016

Nuget in C++ rulez

Home


Source: own resources, Authors: Agnieszka and Michał Komorowscy

I haven't been programming in C++ for a very long time and I didn't expect that I would do it professionally in the foreseeable future. However, the life has different plans ;) Recently, I've joined an extremely interesting project in the area of the computer vision. In a while I'll try to write something about it.

22/11/2016

How to validate dynamic UI with JQuery?

Home


Source: own resources, Authors: Agnieszka and Michał Komorowscy

One of the most interesting task I developed some time ago was a library responsible for the generation of dynamic UI based on XML description in ASP.NET MVC application. The task was not trivial. The UI had to change based on the selections made by a user. I had to support many different types of controls, relations between them e.g. if we select the checkbox A then the text box B should be disabled and of course validations. In order to perform the client side validations I used jQuery Unobtrusive Validation library. I thought that it'll work just like that but it turned out that a dynamic UI may cause problems. Here is what I did.

16/11/2016

3 reasons why I don't use strict mocks

Home


Source: own resources, Authors: Agnieszka and Michał Komorowscy

The majority, if not all, of mocking frameworks provides 2 types of mocks i.e. strict & loose. The difference between them is that the strict mocks will throw an exception if an unexpected (not configured /set up) method was called. I prefer to use loose mocks because with strict ones unit tests are fragile. Even the small change in the code can cause that unit tests will start failing. Secondly, if you need to set up many methods a test becomes less readable. Now, I can see one more reason.

31/10/2016

Roslyn - How to create a custom debuggable scripting language 2?

Home


A screenshot comes from Visual Studio 2015

In the previous post I explained how to create a simple debuggable scripting language based on Roslyn compiler as a service. By debuggable I mean that it can be debugged in Visual Studio as any "normal" program for example written in C#.

27/10/2016

Roslyn - How to create a custom debuggable scripting language?

Home


A screenshot comes from Visual Studio 2015

Sometime ago I decided to play a little bit with Cakebuild. It's a build automation tool/system that allows you to write build scripts using C# domain specific language. What's more it is possible to debug these scripts in Visual Studio. It is interesting because Cake scripts are neither "normal" C# files nor are added to projects (csproj). I was curious how it was achieved and it is result of my analysis. I'll tell you how to create a simple debuggable scripting language. By debuggable I mean that it'll be possible to debug scripts in our language in Visual Studio almost as any "normal" program in C#. Cakebuild uses Roslyn i.e. a compiler as a service from Microsft and we'll do the same.

18/10/2016

Do not forget about GO

Home


Source: own resources, Authors: Agnieszka and Michał Komorowscy

Almost 4 years ago, I wrote a short post in Polish about problems that may occur if we forget about GO keyword in our scripts. I decided to write this post again, this time in English, because recently I helped to fixed exactly the same problem again. As a remainder, GO keyword instructs tools like SQL Management Studio, sqlcmd... to send the batch of T-SQL code to the server. Now, let's look at the following code that creates a stored procedure and tell me what is wrong here:
CREATE PROCEDURE dbo.pr_Fun
AS
BEGIN
    /*...*/
    RETURN
END

GRANT EXECUTE ON dbo.pr_Fun TO public
GO

31/08/2016

AjaxExtensions.BeginForm doesn't work. Really?

Home


Source: own resources, Authors: Agnieszka and Michał Komorowscy

The goal of using Ajax is to communicate with the server asynchronously without reloading the entire page. Specifically AjaxExtensions.BeginForm can be used to updated a selected part of a web page. It is relatively easy in use but can be also troublesome. Especially, when we try to apply it in an application which wasn't using Ajax earlier. I decided to wrote this short technical post because recently I came across the following issue the few times:

AjaxExtensions.BeginForm redirects a user to a new page instead of refreshing a fragment of a current one.

This problem has an easy explanation. Under the hood AjaxExtensions.BeginForm uses Java Script library called Microsoft jQuery Unobtrusive Ajax. The issue is that this library is not installed by default if we create a new project. It's easy to forget about it.

If you have the described problem:
  • Check in packages.config file contains Microsoft.jQuery.Unobtrusive.Ajax package.
  • Check if jquery.unobtrusive-ajax.js file is referenced in html e.g.: <script src="/scripts/jquery.unobtrusive-ajax.js"></script>
  • If you use bundles checik if jquery.unobtrusive-ajax.js was included in a bundle e.g.:
    public static void RegisterBundles(BundleCollection bundles)
    {
       ...
       var js = new ScriptBundle("~/bundles/MyBundle").Include("~/Scripts/jquery.unobtrusive-ajax.js");
       ...
    }
  • Besides, check if a bundle with jquery.unobtrusive-ajax.js is rendered properly e.g.:
    @Scripts.Render("~/bundles/MyBundle")

19/08/2016

My struggels with GitHub, Subtrees and Nuget

Home


Source: own resources, Authors: Agnieszka and Michał Komorowscy

Some time ago I decided to publish my projects on GitHub. This decision had very positive repercussion because it mobilized me to do more refactoring and to clean my solutions. Additionally, I switched totally to management of external references via NuGet. Earlier, I had some binaries in a dedicated directory on my computer. It took me some time but it was worth doing it.

I also had to solve the following problem. I have a solution called Common. It is a collection of libraries, utilities, algorithms, helpers etc. that are used in my other projects. Before migration to GitHub, after a build, all Common binaries were copied to the well known location i.e. N:\bin Thanks to that all other projects could reference them from this location. It works. However, if someone wants to download my projects from GitHub, he or she will need to create a mapped drive N manually. I din't like it.

The next step was to switch from absolute references to binaries to relative references to projects. For example let's consider a library MK.Utilities and a project LanguageTrainer that uses it. Initially LanguageTrainer was referencing:

N:\bin\MK.Utilities.dll

After migration this reference was changed to:

..\..\Common\MK.Utilities\MK.Utilities.csproj

Much more better, isn't it? Still, it is not perfect. This relative path will work only if the folder with Common and LanguageTrainer solutions will be in the same place on the disk. Besides, in order to compile LanguageTrainer solution Common solution must be built first. What's more Common and LanguageTrainer are two separate repositories which have to be downloaded individually. My goal was to be able to download any repository/solution and then be able to compile it without any further steps.

I started reading about possible solutions and I found information about git submodules and git subtrees. There is so much about them in Internet so I will not repeat others. For example see this post. At the end I decided to use subtrees. Simplifying a subtree is a copy of some repository in the another one. Returning to my earlier example, by using subtrees I got a copy of Common repository/solution in LanguageTrainer repository/solution. Then I could change the reference to MK.Utilities as follows:

..\Common\MK.Utilities\MK.Utilities.csproj

Besides, I needed to add MK.Utilities project to LanguageTrainer.sln solution so that all projects could be build at the same time. Finally, my LanguageTrainer repository/solution looks in the following way. On left side you can see GitHub and on the right side Visual Studio:


If needed I can refresh a copy of Common repository/solution inside LanguageTrainer at any time. Why I used subtrees? Well, they work for me and are extreamly easy to create via Source Tree ;) By the way, I like git but I hate all this complex commands. Source Tree solves this problem and allows me to use git via friendly GUI. I strongly recommend it.

At the end I had to solve one more problem with Nuget. Let's return again to my example and let's assume that LanguageTrainer solution is located here:

C:\LanguageTrainer

In that case, by default, Nuget packages will be located here:

C:\LanguageTrainer\packages

However, we also have a subtree:

C:\LanguageTrainer\Common

And projects from a subtree expects that their packages will be here:

C:\LanguageTrainer\Common\packages

Of course they won't be there so Common projects will not compile. To overcome this problem I had to manually update csproj files and replace ..\packages with $(Solutiondir)packages. For example:

..\packages\structuremap.3.1.6.186\lib\net40\StructureMap.dll

Was changed as follows:

$(SolutionDir)packages\structuremap.3.1.6.186\lib\net40\StructureMap.dll

I hope that this post will help you in your struggles with GitHub, Subtrees and Nuget.

18/03/2016

Two things I learned about HTML and CSS

Home

I've never worked a lot of with CSS. However, from time to time I do something with it, for example in order to check out new possibilities. Recently, I read about CSS transformations and I decided to give it a try. For the beginning I wanted to achieve a very simple effect i.e. a red square with a blue and a green diagonal lines. It sounds simple and it is simple but there are traps in this exercise. I decided to write this post because it took me a moment to figure out that was wrong. It was also difficult to find a solution in Internet. Maybe because it is so obvious ;)

My idea was to use 3 div elements. One for a square and 2 for diagonal lines. I also wanted to use transformations in order to rotate divs so that they look like diagonals. My first attempt looks as follows. Do you know what is wrong? There are 2 main problems here.

Scroll down if you want to see a correct solution:
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.


I changed two things, one in html and one in CSS:
  • The first problem was that I used div as a self closing tag. It is not allowed. Browsers treat <div /> as <div >. It is quite difficult to spot.
  • The second problem was in the greenLine style. It was not enough to rotate the green div by 45 degrees. Firstly we need to translate it in this way: translate(100px,-141px) rotate(45deg). It might be surprising because in the case of the blue div the rotation was enough. However, we we have to remember that the green div is not located in the origin of the coordinate system but just below the blue div. The blue div looks like a thin line but it's height is set to 141 pixels.