Diffing Folder Content using ItemGroups

More on complicated build systems. This time, I was attempting to make the complicated build faster by removing work that only needs to be done on release builds but is currently scattered across post build events, batch files and msbuild scripts so that it is done regardless of the build being done and slowing things down.

The extra work also contributes components and artefacts that, if incorrect, won’t break the build but will cause problems once the application is deployed.

Since the work is in multiple solutions, projects and batch files, each with their own working directory and set of environmental assumption, it’s not easy to see whether my changes have missed anything, are copying the wrong files, are copying the right files to the wrong location.

What I came up with is a simple build script that can be run once against the known good, “golden copy” of a build with the time sucking work still in place. I can then put my changes in place and run the script again and just use a nice diffing tool like kdiff3 to check for differences in the build output.

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

    <PropertyGroup>
	    <BinariesDir Condition=" '$(BinariesDir)' == '' ">D:\dev\project\bin\debug\</BinariesDir>
	    <OutputFile Condition=" '$(OutputFile)' == '' ">D:\First.txt</OutputFile>
    </PropertyGroup>	

    <Target Name="CaptureBuildOutput">
	
	    <ItemGroup>
		    <Binaries Include="$(BinariesDir)**\*.*" />
	    </ItemGroup>
	
	    <WriteLinesToFile 
		    Lines="@(Binaries)" 
		    File="$(OutputFile)" 
		    Encoding="Unicode" 
		    />
		
    </Target>

</Project>

Essentially, all the script does is list the content of the output folder and write it to a file. I could have achieved the same by running dir or ls command in a console window and redirecting to a file. The only reason I wanted to massively over engineer it in msbuild was so I could hook it up to the old and new build scripts and have it run as part of the build.