a msbuild target file creating a CommonAssemblyInfo.cs based on `git describe`

PreBuild.targets.xml

<?xml version="1.0" encoding="utf-8" ?>
<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">

  <UsingTask
    TaskName="GetVersion"
    TaskFactory="CodeTaskFactory"
    AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.v4.0.dll" >
    <ParameterGroup>
      <VersionString ParameterType="System.String" Required="true" />
      <Version ParameterType="System.String" Output="true" />
      <Commit ParameterType="System.String" Output="true" />
      <VersionSuffix ParameterType="System.String" Output="true" />
    </ParameterGroup>
    <Task>
      <!--<Reference Include="" />-->
      <Using Namespace="System"/>
      <Using Namespace="System.IO"/>
      <Using Namespace="System.Text.RegularExpressions" />
      <Code Type="Fragment" Language="cs">
        <![CDATA[
          var match = Regex.Match(VersionString, @"^v(?<major>\d+)\.(?<minor>\d+)(\.(?<patch>\d+))?-(?<revision>\d+)-(?<commit>[a-z0-9]+)$");
          int major, minor, patch, revision;
          Int32.TryParse(match.Groups["major"].Value, out major);
          Int32.TryParse(match.Groups["minor"].Value, out minor);
          Int32.TryParse(match.Groups["patch"].Value, out patch);
          Int32.TryParse(match.Groups["revision"].Value, out revision);
          _Version = new Version(major, minor, patch, revision).ToString();
          _VersionSuffix = revision == 0 ? String.Empty : "-Beta";
          _Commit = match.Groups["commit"].Value;
        ]]>
      </Code>
    </Task>
  </UsingTask>

  <UsingTask
    TaskName="ExistsInPath"
    TaskFactory="CodeTaskFactory"
    AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.v4.0.dll" >
    <ParameterGroup>
      <FileName ParameterType="System.String" Required="true" />
      <Exists ParameterType="System.Boolean" Output="true" />
    </ParameterGroup>
    <Task>
      <!--<Reference Include="" />-->
      <Using Namespace="System"/>
      <Using Namespace="System.IO"/>
      <Using Namespace="System.Text.RegularExpressions" />
      <Code Type="Fragment" Language="cs">
        <![CDATA[
        var values = Environment.GetEnvironmentVariable("PATH");
        foreach (var path in values.Split(';')) {
            var fullPath = Path.Combine(path, FileName);
            if (File.Exists(fullPath)) {
                Exists = true;
                return true;
            }
        }
        Exists = false;
        ]]>
      </Code>
    </Task>
  </UsingTask>

  <Target Name="CreateCommonVersionInfo" BeforeTargets="CoreCompile">
    <Message Importance="high" Text="CreateCommonVersionInfo" />

    <ExistsInPath FileName="git.cmd">
      <Output TaskParameter="Exists" PropertyName="GitExists"/>
    </ExistsInPath>
    <Message Importance="High" Text="git not found!" Condition="!$(GitExists)"/>
      
    <Exec Command="git describe --tags --long > $(ProjectDir)version.txt" Outputs="$(ProjectDir)version.txt" WorkingDirectory="$(SolutionDir)" IgnoreExitCode="true" Condition="$(GitExists)">
      <Output TaskParameter="ExitCode" PropertyName="ExitCode" />
    </Exec>
    <Message Importance="high" Text="Calling git failed with exit code $(ExitCode)" Condition="$(GitExists) And '$(ExitCode)'!='0'" />
    
    <ReadLinesFromFile File="$(ProjectDir)version.txt" Condition="$(GitExists) And '$(ExitCode)'=='0'">
      <Output TaskParameter="Lines" ItemName="OutputLines"/>
    </ReadLinesFromFile>
    <Message Importance="High" Text="Tags: @(OutputLines)" Condition="$(GitExists) And '$(ExitCode)'=='0'"/>
    <Delete Condition="Exists('$(ProjectDir)version.txt')" Files="$(ProjectDir)version.txt"/>

    <GetVersion VersionString="@(OutputLines)" Condition="$(GitExists) And '$(ExitCode)'=='0'">
      <Output TaskParameter="Version" PropertyName="VersionString"/>
      <Output TaskParameter="Commit" PropertyName="Commit"/>
      <Output TaskParameter="VersionSuffix" PropertyName="VersionSuffix"/>
    </GetVersion>
      
    <PropertyGroup>
      <VersionString Condition="'$(VersionString)'==''">0.0.0.0</VersionString>
    </PropertyGroup>

    <Message Importance="High" Text="Creating CommonVersionInfo.cs with version $(VersionString) $(Commit)" />

    <WriteLinesToFile Overwrite="true" File="$(ProjectDir)CommonAssemblyInfo.cs" Encoding="UTF-8" Lines='using System.Reflection%3B

// full version: $(VersionString)-$(Commit)

[assembly: AssemblyVersion("$(VersionString)")]
[assembly: AssemblyInformationalVersion("$(VersionString)$(VersionSuffix)")] 
[assembly: AssemblyFileVersion("$(VersionString)")]' />
    
  </Target>
</Project>

a msbuild target file creating a CommonAssemblyInfo.cs based on git describe