MSBuild Task CopyIfNewer

msbuild_task_copyifnewer.targets

<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
    <UsingTask TaskName="CopyIfNewer" TaskFactory="RoslynCodeTaskFactory" AssemblyFile="$(MSBuildBinPath)\Microsoft.Build.Tasks.Core.dll">
        <ParameterGroup>
            <SourceFiles ParameterType="Microsoft.Build.Framework.ITaskItem[]" Required="true"/>
            <TargetFiles ParameterType="Microsoft.Build.Framework.ITaskItem[]" Required="true"/>
        </ParameterGroup>
        <Task>
            <Using Namespace="System"/>
            <Using Namespace="System.IO"/>
            <Using Namespace="Microsoft.Build.Framework"/>
            <Using Namespace="Microsoft.Build.Utilities"/>
            <Code Type="Fragment" Language="cs">
                <![CDATA[
                  Success = SourceFiles.Length == TargetFiles.Length;
                  if (!Success)
                  {
                      Log.LogError("SourceFiles and TargetFiles must have the same number of elements.");
                  }
                  else
                  {
                    for (int i = 0; i < SourceFiles.Length; i++)
                    {
                        string sourceFile = SourceFiles[i].ItemSpec;
                        string targetFile = TargetFiles[i].ItemSpec;
            
                        if (!File.Exists(sourceFile))
                        {
                            Log.LogMessage(MessageImportance.High, $"Source file does not exist: {sourceFile}");
                            continue;
                        }
            
                        bool shouldCopy = !File.Exists(targetFile);
                        bool sameModified = false;
                        if (!shouldCopy)
                        {
                            var sourceLastModified = File.GetLastWriteTime(sourceFile);
                            var targetLastModified = File.GetLastWriteTime(targetFile);
                            shouldCopy = sourceLastModified > targetLastModified;
                            sameModified = sourceLastModified == targetLastModified;
                        }
                        
                        if (shouldCopy)
                        {
                            try
                            {
                                File.Copy(sourceFile, targetFile, true);
                                Log.LogMessage(MessageImportance.High, $"Copied file '{sourceFile}' -> '{targetFile}' succeed.");
                            }
                            catch (Exception ex)
                            {
                                Log.LogError($"Error copying '{sourceFile}' to '{targetFile}': {ex.Message}");
                                Success = false;
                                break;
                            }
                        } else {
                            string reason = sameModified ? "same modified time" : "target is newer";
                            Log.LogMessage(MessageImportance.High, $"Skipping copy file '{sourceFile}' -> '{targetFile}' ({reason})");
                        }
                    }
                  }
                ]]>
            </Code>
        </Task>
    </UsingTask>

    <Target Name="CopyFiles">
        <ItemGroup>
            <SourceFiles Include="path\to\source\file1.txt;path\to\source\file2.txt" />
            <TargetFiles Include="path\to\target\file1.txt;path\to\target\file2.txt" />
        </ItemGroup>

        <CopyIfNewer SourceFiles="@(SourceFiles)" TargetFiles="@(TargetFiles)" />
    </Target>
</Project>

Same can be done by complicated way using msbuild only stuff, example:

<ItemGroup>
    <AppSettingsFilesToCopyWithTime Include="@(PackageWebModuleAppSettingsFiles->'$(TargetDir)\%(RecursiveDir)$(PackageWebModuleName).%(Filename)%(Extension)')">
        <OriginalIdentity>%(RootDir)%(Directory)%(Filename)%(Extension)</OriginalIdentity>
        <SourceTime>$([System.DateTime]::Parse('%(ModifiedTime)').Ticks)</SourceTime>
        <CanOverwrite></CanOverwrite>
    </AppSettingsFilesToCopyWithTime>

    <AppSettingsFilesToCopy_ Include="@(AppSettingsFilesToCopyWithTime)">
        <CanOverwrite Condition="!Exists('%(Identity)') Or '%(SourceTime)' > $([System.DateTime]::Parse('%(ModifiedTime)').Ticks)">true</CanOverwrite>
    </AppSettingsFilesToCopy_>

    <AppSettingsFilesToCopy Include="@(AppSettingsFilesToCopy_->'%(OriginalIdentity)')" Condition="'%(CanOverwrite)' == 'true'" />
</ItemGroup>

<Copy SourceFiles="@(AppSettingsFilesToCopy)"
      DestinationFiles="@(AppSettingsFilesToCopy->'$(TargetDir)\%(RecursiveDir)\$(PackageWebModuleName).%(Filename)%(Extension)')"
      OverwriteReadOnlyFiles="true" />