private Dictionary <string, PackageOverride> BuildPackageOverrides() { Dictionary <string, PackageOverride> result; if (_packageOverrideItems?.Length > 0) { result = new Dictionary <string, PackageOverride>(_packageOverrideItems.Length, StringComparer.OrdinalIgnoreCase); foreach (ITaskItem packageOverrideItem in _packageOverrideItems) { PackageOverride packageOverride = PackageOverride.Create(packageOverrideItem); if (result.TryGetValue(packageOverride.PackageName, out PackageOverride existing)) { MergePackageOverrides(packageOverride, existing); } else { result[packageOverride.PackageName] = packageOverride; } } } else { result = null; } return(result); }