(chocolatey#1092) Update NugetCommon.GetPackageManager()

This update is necessary for easy access to the PackageInstalling
and PackageUninstalling event handlers which we need to utilise to
ensure we're properly handling backing up and beforeModify scripts of
package dependencies as well as the main packages we're modifying.

src/chocolatey/infrastructure.app/nuget/NugetCommon.cs

@@ -173,10 +173,10 @@ public static IPackageRepository GetRemoteRepository(ChocolateyConfiguration con
         // keep this here for the licensed edition for now
         public static IPackageManager GetPackageManager(ChocolateyConfiguration configuration, ILogger nugetLogger, Action<PackageOperationEventArgs> installSuccessAction, Action<PackageOperationEventArgs> uninstallSuccessAction, bool addUninstallHandler)
         {
-            return GetPackageManager(configuration, nugetLogger, new PackageDownloader(), installSuccessAction, uninstallSuccessAction, addUninstallHandler);
+            return GetPackageManager(configuration, nugetLogger, new PackageDownloader(), installSuccessAction, uninstallSuccessAction, beforeModifyAction: null, addUninstallHandler);
         }
 
-        public static IPackageManager GetPackageManager(ChocolateyConfiguration configuration, ILogger nugetLogger, IPackageDownloader packageDownloader, Action<PackageOperationEventArgs> installSuccessAction, Action<PackageOperationEventArgs> uninstallSuccessAction, bool addUninstallHandler)
+        public static IPackageManager GetPackageManager(ChocolateyConfiguration configuration, ILogger nugetLogger, IPackageDownloader packageDownloader, Action<PackageOperationEventArgs> installSuccessAction, Action<PackageOperationEventArgs> uninstallSuccessAction, Action<PackageOperationEventArgs> beforeModifyAction, bool addUninstallHandler)
         {
             IFileSystem nugetPackagesFileSystem = GetNuGetFileSystem(configuration, nugetLogger);
             IPackagePathResolver pathResolver = GetPathResolver(configuration, nugetPackagesFileSystem);
@@ -205,6 +205,21 @@ public static IPackageManager GetPackageManager(ChocolateyConfiguration configur
                     if (installSuccessAction != null) installSuccessAction.Invoke(e);
                 };
 
+            if (beforeModifyAction != null)
+            {
+                // These event handlers MUST NOT call back into their corresponding packageManager methods -- InstallPackage() / UninstallPackage()
+                // Doing so will cause them to be liable to loop indefinitely, and we don't want that.
+                packageManager.PackageInstalling += (sender, eventArgs) =>
+                {
+                    beforeModifyAction(eventArgs);
+                };
+
+                packageManager.PackageUninstalling += (sender, eventArgs) =>
+                {
+                    beforeModifyAction(eventArgs);
+                };
+            }
+
             if (addUninstallHandler)
             {
                 // NOTE DO NOT EVER use this method, or endless loop - packageManager.PackageUninstalling += (s, e) =>