Update to net46

src/CommandLineUtils/Abstractions/ValueParserProvider.cs

@@ -61,7 +61,7 @@ private static readonly MethodInfo s_getParserGeneric
         public IValueParser GetParser(Type type)
         {
             var method = s_getParserGeneric.MakeGenericMethod(type);
-            return (IValueParser)method.Invoke(this, Util.EmptyArray<object>());
+            return (IValueParser)method.Invoke(this, Array.Empty<object>());
         }
 
         /// <summary>

src/CommandLineUtils/Attributes/CommandAttribute.cs

@@ -14,7 +14,7 @@ namespace McMaster.Extensions.CommandLineUtils
     [AttributeUsage(AttributeTargets.Class)]
     public sealed class CommandAttribute : Attribute
     {
-        private string[] _names = Util.EmptyArray<string>();
+        private string[] _names = Array.Empty<string>();
 
         /// <summary>
         /// Initializes a new <see cref="CommandAttribute"/>.
@@ -55,7 +55,7 @@ public string? Name
                 }
                 else
                 {
-                    _names = Util.EmptyArray<string>();
+                    _names = Array.Empty<string>();
                 }
             }
         }

src/CommandLineUtils/Attributes/VersionOptionFromMemberAttribute.cs

@@ -60,7 +60,7 @@ internal CommandOption Configure(CommandLineApplication app, Type type, Func<obj
 
                 shortFormGetter = () =>
                 {
-                    return (string)methods[0].Invoke(targetInstanceFactory.Invoke(), Util.EmptyArray<object>());
+                    return (string)methods[0].Invoke(targetInstanceFactory.Invoke(), Array.Empty<object>());
                 };
             }
 

src/CommandLineUtils/CommandLineApplication.Execute.cs

@@ -129,7 +129,7 @@ public static int Execute<TApp>(params string[] args)
         public static int Execute<TApp>(IConsole console, params string[] args)
             where TApp : class
         {
-            args ??= Util.EmptyArray<string>();
+            args ??= Array.Empty<string>();
             var context = new DefaultCommandLineContext(console, Directory.GetCurrentDirectory(), args);
             return Execute<TApp>(context);
         }
@@ -168,7 +168,7 @@ public static Task<int> ExecuteAsync<TApp>(string[] args, CancellationToken canc
 #pragma warning restore RS0026 // Do not add multiple public overloads with optional parameters
         where TApp : class
         {
-            args ??= Util.EmptyArray<string>();
+            args ??= Array.Empty<string>();
             var context = new DefaultCommandLineContext(PhysicalConsole.Singleton, Directory.GetCurrentDirectory(), args);
             return ExecuteAsync<TApp>(context, cancellationToken);
         }
@@ -189,7 +189,7 @@ public static Task<int> ExecuteAsync<TApp>(string[] args, CancellationToken canc
         public static Task<int> ExecuteAsync<TApp>(IConsole console, params string[] args)
             where TApp : class
         {
-            args ??= Util.EmptyArray<string>();
+            args ??= Array.Empty<string>();
             var context = new DefaultCommandLineContext(console, Directory.GetCurrentDirectory(), args);
             return ExecuteAsync<TApp>(context);
         }

src/CommandLineUtils/CommandLineApplication.cs

@@ -748,7 +748,7 @@ public ParseResult Parse(params string[] args)
         {
             Reset();
 
-            args ??= Util.EmptyArray<string>();
+            args ??= Array.Empty<string>();
 
             var processor = new CommandLineProcessor(this, args);
             var result = processor.Process();

src/CommandLineUtils/Conventions/OptionAttributeConventionBase.cs

@@ -131,7 +131,7 @@ private protected void AddOption(ConventionContext context, CommandOption option
                         {
                             if (!option.HasValue())
                             {
-                                setter.Invoke(modelAccessor.GetModel(), Util.EmptyArray<bool>());
+                                setter.Invoke(modelAccessor.GetModel(), Array.Empty<bool>());
                             }
 
                             var count = new bool[option.Values.Count];

src/CommandLineUtils/HelpText/DefaultHelpTextGenerator.cs

@@ -413,7 +413,7 @@ private string[] ExtractNamesFromEnum(Type? type)
         {
             if (type == null)
             {
-                return Util.EmptyArray<string>();
+                return Array.Empty<string>();
             }
 
             if (ReflectionHelper.IsNullableType(type, out var wrappedType))
@@ -431,7 +431,7 @@ private string[] ExtractNamesFromEnum(Type? type)
                 return Enum.GetNames(type);
             }
 
-            return Util.EmptyArray<string>();
+            return Array.Empty<string>();
         }
     }
 }

src/CommandLineUtils/IO/Pager.cs

@@ -42,10 +42,10 @@ public Pager(IConsole console)
                 throw new ArgumentNullException(nameof(console));
             }
 
-#if NET45
+#if NET46_OR_GREATER
             // if .NET Framework, assume we're on Windows unless it's running on Mono.
             _enabled = Type.GetType("Mono.Runtime") != null;
-#elif NETSTANDARD2_0 || NETSTANDARD2_1
+#elif NETSTANDARD2_0_OR_GREATER
             _enabled = !RuntimeInformation.IsOSPlatform(OSPlatform.Windows) && !console.IsOutputRedirected;
 #else
 #error Update target frameworks
@@ -130,7 +130,7 @@ public void Kill()
                     FileName = "less",
                     Arguments = ArgumentEscaper.EscapeAndConcatenate(args),
                     RedirectStandardInput = true,
-#if NET45
+#if NET46_OR_GREATER
                     UseShellExecute = false,
 #endif
                 }

src/CommandLineUtils/Internal/ValueParsers/HashSetParser.cs

@@ -25,7 +25,7 @@ public HashSetParser(Type elementType, IValueParser elementParser, CultureInfo p
 
         public object Parse(string? argName, IReadOnlyList<string?> values)
         {
-            var set = Activator.CreateInstance(_listType, Util.EmptyArray<object>());
+            var set = Activator.CreateInstance(_listType, Array.Empty<object>());
             foreach (var t in values)
             {
                 _addMethod.Invoke(set, new[] { _elementParser.Parse(argName, t, _parserCulture) });

src/CommandLineUtils/McMaster.Extensions.CommandLineUtils.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netstandard2.1;netstandard2.0;net45</TargetFrameworks>
+    <TargetFrameworks>netstandard2.1;netstandard2.0;net46</TargetFrameworks>
     <Nullable Condition="'$(TargetFramework)' != 'netstandard2.1'">annotations</Nullable>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <IsPackable>true</IsPackable>
@@ -26,7 +26,7 @@ McMaster.Extensions.CommandLineUtils.ArgumentEscaper
     <PackageReference Include="System.ComponentModel.Annotations" Version="5.0.0" />
   </ItemGroup>
 
-  <ItemGroup Condition="'$(TargetFramework)' == 'net45'">
+  <ItemGroup Condition="'$(TargetFramework)' == 'net46'">
     <Reference Include="System.ComponentModel.DataAnnotations" />
     <PackageReference Include="System.Runtime.InteropServices.RuntimeInformation" Version="4.3.0" />
     <PackageReference Include="System.ValueTuple" Version="4.5.0" />

src/CommandLineUtils/Properties/NullabilityHelpers.cs

@@ -2,7 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 // Files here are for simplify annotations of nullable code and are not functional in .NET Standard 2.0
-#if NETSTANDARD2_0 || NET45
+#if NETSTANDARD2_0 || NET46_OR_GREATER
 namespace System.Diagnostics.CodeAnalysis
 {
     // https://docs.microsoft.com/en-us/dotnet/api/system.diagnostics.codeanalysis.notnullwhenattribute?

src/CommandLineUtils/Utilities/DotNetExe.cs

@@ -43,9 +43,9 @@ public static string FullPathOrDefault()
         private static string? TryFindDotNetExePath()
         {
             var fileName = FileName;
-#if NET45
+#if NET46_OR_GREATER
             fileName += ".exe";
-#elif NETSTANDARD2_0 || NETSTANDARD2_1
+#elif NETSTANDARD2_0_OR_GREATER
             if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
             {
                 fileName += ".exe";
@@ -60,10 +60,17 @@ public static string FullPathOrDefault()
 #else
 #error Update target frameworks
 #endif
+            // DOTNET_ROOT specifies the location of the .NET runtimes, if they are not installed in the default location.
             var dotnetRoot = Environment.GetEnvironmentVariable("DOTNET_ROOT");
-            return !string.IsNullOrEmpty(dotnetRoot)
-                ? Path.Combine(dotnetRoot, fileName)
-                : null;
+
+            if (string.IsNullOrEmpty(dotnetRoot))
+            {
+                // fall back to default location
+                // https://learn.microsoft.com/en-us/dotnet/core/tools/dotnet-environment-variables#dotnet_root-dotnet_rootx86
+                dotnetRoot = RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? "C:\\Program Files\\dotnet" : "/usr/local/share/dotnet";
+            }
+
+            return Path.Combine(dotnetRoot, fileName);
         }
     }
 }

test/CommandLineUtils.Tests/ExecuteMethodConventionTests.cs

@@ -105,7 +105,7 @@ public void OnExecuteIsExecutedOnSelectedSubcommand(string? args, int expectedRe
             app.Conventions.UseCommandAttribute();
             app.Conventions.UseOnExecuteMethodFromModel();
 
-            var result = app.Execute(args?.Split(' ') ?? Util.EmptyArray<string>());
+            var result = app.Execute(args?.Split(' ') ?? Array.Empty<string>());
             Assert.Equal(expectedResult, result);
         }
 

test/CommandLineUtils.Tests/OptionAttributeTests.cs

@@ -302,7 +302,7 @@ private CommandOption CreateOption(Type propType, string propName)
             pb.SetCustomAttribute(ab);
             var program = tb.CreateType();
             var appBuilder = typeof(CommandLineApplication<>).MakeGenericType(program);
-            var app = (CommandLineApplication)Activator.CreateInstance(appBuilder, Util.EmptyArray<object>());
+            var app = (CommandLineApplication)Activator.CreateInstance(appBuilder, Array.Empty<object>());
             app.Conventions.UseOptionAttributes();
             return app.Options.First();
         }