Re-enable deterministic nuget pack

Deterministic support was disabled due to various concerns some time
ago: NuGet/Home#8601

This PR re-enables deterministic support, while adding support for
SOURCE_DATE_EPOCH to override it. SOURCE_DATE_EPOCH is specified at:
https://reproducible-builds.org/docs/source-date-epoch/

Author: omajid

src/NuGet.Clients/NuGet.CommandLine/Commands/PackCommand.cs

@@ -103,6 +103,9 @@ public Dictionary<string, string> Properties
         [Option(typeof(NuGetCommand), "PackageCommandConfigFile")]
         public new string ConfigFile { get; set; }
 
+        [Option(typeof(NuGetCommand), "PackageCommandDeterministic")]
+        public bool Deterministic { get; set; }
+
         public override void ExecuteCommand()
         {
             var packArgs = new PackArgs();
@@ -111,6 +114,7 @@ public override void ExecuteCommand()
             packArgs.OutputDirectory = OutputDirectory;
             packArgs.BasePath = BasePath;
             packArgs.MsBuildDirectory = new Lazy<string>(() => MsBuildUtility.GetMsBuildDirectoryFromMsBuildPath(MSBuildPath, MSBuildVersion, Console).Value.Path);
+            packArgs.Deterministic = Deterministic;
 
             if (!string.IsNullOrEmpty(PackagesDirectory))
             {

src/NuGet.Core/NuGet.Packaging/PackageCreation/Authoring/PackageBuilder.cs

@@ -5,6 +5,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Collections.Immutable;
 using System.Collections.ObjectModel;
 using System.Diagnostics;
 using System.Globalization;
@@ -32,9 +33,11 @@ public class PackageBuilder : IPackageMetadata
         private static readonly DateTime ZipFormatMinDate = new DateTime(1980, 1, 1, 0, 0, 0, DateTimeKind.Utc);
         private static readonly DateTime ZipFormatMaxDate = new DateTime(2107, 12, 31, 23, 59, 58, DateTimeKind.Utc);
         internal const string ManifestRelationType = "manifest";
+        private readonly IEnvironmentVariableReader _environmentVariableProvider;
         private readonly bool _includeEmptyDirectories;
         private readonly bool _deterministic;
         private readonly ILogger _logger;
+        private readonly DateTime _deterministicDate;
 
         /// <summary>
         /// Maximum Icon file size: 1 megabyte
@@ -68,7 +71,7 @@ public PackageBuilder(string path, string basePath, Func<string, string> propert
         }
 
         public PackageBuilder(string path, string basePath, Func<string, string> propertyProvider, bool includeEmptyDirectories, bool deterministic)
-            : this(includeEmptyDirectories, deterministic)
+            : this(EnvironmentVariableWrapper.Instance, includeEmptyDirectories, deterministic)
         {
             if (!File.Exists(path))
             {
@@ -95,30 +98,32 @@ public PackageBuilder(Stream stream, string basePath, Func<string, string> prope
         }
 
         public PackageBuilder(bool deterministic) :
-            this(includeEmptyDirectories: false, deterministic: deterministic)
+            this(EnvironmentVariableWrapper.Instance, includeEmptyDirectories: false, deterministic: deterministic)
         {
 
         }
 
         public PackageBuilder()
-            : this(includeEmptyDirectories: false, deterministic: false)
+            : this(EnvironmentVariableWrapper.Instance, includeEmptyDirectories: false, deterministic: false)
         {
         }
 
         public PackageBuilder(bool deterministic, ILogger logger)
-            : this(includeEmptyDirectories: false, deterministic: deterministic, logger)
+            : this(EnvironmentVariableWrapper.Instance, includeEmptyDirectories: false, deterministic: deterministic, logger)
         {
         }
 
-        private PackageBuilder(bool includeEmptyDirectories, bool deterministic)
-            : this(includeEmptyDirectories: false, deterministic: deterministic, logger: NullLogger.Instance)
+        private PackageBuilder(IEnvironmentVariableReader environmentVariableProvider, bool includeEmptyDirectories, bool deterministic)
+            : this(environmentVariableProvider, includeEmptyDirectories: false, deterministic: deterministic, logger: NullLogger.Instance)
         {
         }
 
-        private PackageBuilder(bool includeEmptyDirectories, bool deterministic, ILogger logger)
+        private PackageBuilder(IEnvironmentVariableReader environmentVariableProvider, bool includeEmptyDirectories, bool deterministic, ILogger logger)
         {
+            _environmentVariableProvider = environmentVariableProvider;
             _includeEmptyDirectories = includeEmptyDirectories;
-            _deterministic = false; // fix in https://github.com/NuGet/Home/issues/8601
+            _deterministic = deterministic;
+            _deterministicDate = ComputeDeterministicDate();
             _logger = logger;
             Files = new Collection<IPackageFile>();
             DependencyGroups = new Collection<PackageDependencyGroup>();
@@ -135,6 +140,20 @@ private PackageBuilder(bool includeEmptyDirectories, bool deterministic, ILogger
             Properties = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
         }
 
+        private DateTime ComputeDeterministicDate()
+        {
+            string sourceBuildEpoch = _environmentVariableProvider.GetEnvironmentVariable("SOURCE_DATE_EPOCH");
+            if (sourceBuildEpoch != null &&
+                long.TryParse(sourceBuildEpoch, NumberStyles.None, CultureInfo.InvariantCulture, out long unixTimeSeconds))
+            {
+                return DateTimeOffset.FromUnixTimeSeconds(unixTimeSeconds).UtcDateTime;
+            }
+            else
+            {
+                return ZipFormatMinDate;
+            }
+        }
+
         public string Id
         {
             get;
@@ -1004,7 +1023,7 @@ private ZipArchiveEntry CreateEntry(ZipArchive package, string entryName, Compre
             var entry = package.CreateEntry(entryName, compressionLevel);
             if (_deterministic)
             {
-                entry.LastWriteTime = ZipFormatMinDate;
+                entry.LastWriteTime = _deterministicDate;
             }
             return entry;
         }
@@ -1060,7 +1079,7 @@ private SortedSet<string> WriteFiles(ZipArchive package, SortedSet<string> files
                         package,
                         file.Path,
                         stream,
-                        lastWriteTime: _deterministic ? ZipFormatMinDate : file.LastWriteTime,
+                        lastWriteTime: _deterministic ? _deterministicDate : file.LastWriteTime,
                         warningMessage);
                     var fileExtension = Path.GetExtension(file.Path);
 

test/NuGet.Clients.Tests/NuGet.CommandLine.Test/NuGetPackCommandTest.cs

@@ -6296,7 +6296,7 @@ private static void VerifyNuspecRoundTrips(PackageArchiveReader nupkgReader, str
             }
         }
 
-        [Fact(Skip = "https://github.com/NuGet/Home/issues/8601")]
+        [Fact]
         public void PackCommand_Deterministic_MultiplePackInvocations_CreateIdenticalPackages()
         {
             var nugetexe = Util.GetNuGetExePath();

test/NuGet.Core.FuncTests/Dotnet.Integration.Test/PackCommandTests.cs

@@ -4950,7 +4950,7 @@ public void PackCommand_WithGeneratePackageOnBuildSet_CanPublish()
             }
         }
 
-        [PlatformFact(Platform.Windows, Skip = "https://github.com/NuGet/Home/issues/8601")]
+        [PlatformFact(Platform.Windows)]
         public void PackCommand_Deterministic_MultiplePackInvocations_CreateIdenticalPackages()
         {
             using (var testDirectory = _dotnetFixture.CreateTestDirectory())