Nullable annotations for most of NuGet.ProjectModel (#7172)

nkolev92 · web-flow · commit 115813246d3f · 2026-02-27T14:58:45.000-08:00
diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md
@@ -1,9 +1,15 @@
 # Instructions
 
-When creating pull requests, always follow the [PR template](PULL_REQUEST_TEMPLATE.md).
+## General Guidelines
 
-Use the following coding guidelines: https://github.com/NuGet/NuGet.Client/blob/dev/docs/coding-guidelines.md
+- When creating pull requests, always follow the [PR template](PULL_REQUEST_TEMPLATE.md).
+- Always format before submitting a pull request.
 
-Always format before submitting a pull request.
+## Coding Standards
 
-Never use reflection.
+- Use the following coding guidelines: https://github.com/NuGet/NuGet.Client/blob/dev/docs/coding-guidelines.md
+- Never use reflection.
+
+## Project-Specific Rules
+
+- All files in the repository are nullable by default (project-level nullable enable). No need to add `#nullable enable` directives to individual files.
diff --git a/src/NuGet.Core/NuGet.Common/MsBuildStringUtility.cs b/src/NuGet.Core/NuGet.Common/MsBuildStringUtility.cs
@@ -91,7 +91,7 @@ public static bool IsTrueOrEmpty(string? value)
         /// </summary>
         /// <param name="s">A comma or semicolon delimited list of NuGet log codes.</param>
         /// <returns>An <see cref="IList{T}" /> containing the <see cref="NuGetLogCode" /> values that were successfully parsed from the specified string.</returns>
-        public static ImmutableArray<NuGetLogCode> GetNuGetLogCodes(string s)
+        public static ImmutableArray<NuGetLogCode> GetNuGetLogCodes(string? s)
         {
             // The Split() method already checks for an empty string and returns Array.Empty<string>().
             string[] split = MSBuildStringUtility.Split(s, ';', ',');
diff --git a/src/NuGet.Core/NuGet.Common/PublicAPI.Shipped.txt b/src/NuGet.Core/NuGet.Common/PublicAPI.Shipped.txt
@@ -576,7 +576,7 @@ static NuGet.Common.LoggingExtensions.GetName(this NuGet.Common.NuGetLogCode cod
 static NuGet.Common.LoggingExtensions.TryGetName(this NuGet.Common.NuGetLogCode code, out string? codeString) -> bool
 static NuGet.Common.MSBuildStringUtility.Convert(string? value) -> string?
 static NuGet.Common.MSBuildStringUtility.GetBooleanOrNull(string? value) -> bool?
-static NuGet.Common.MSBuildStringUtility.GetNuGetLogCodes(string! s) -> System.Collections.Immutable.ImmutableArray<NuGet.Common.NuGetLogCode>
+static NuGet.Common.MSBuildStringUtility.GetNuGetLogCodes(string? s) -> System.Collections.Immutable.ImmutableArray<NuGet.Common.NuGetLogCode>
 static NuGet.Common.MSBuildStringUtility.IsTrue(string? value) -> bool
 static NuGet.Common.MSBuildStringUtility.IsTrueOrEmpty(string? value) -> bool
 static NuGet.Common.MSBuildStringUtility.Split(string? s) -> string![]!
diff --git a/src/NuGet.Core/NuGet.ProjectModel/CentralTransitiveDependencyGroup.cs b/src/NuGet.Core/NuGet.ProjectModel/CentralTransitiveDependencyGroup.cs
@@ -1,8 +1,6 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-#nullable disable
-
 using System;
 using System.Collections.Generic;
 using NuGet.Frameworks;
@@ -32,7 +30,7 @@ public CentralTransitiveDependencyGroup(NuGetFramework framework, IEnumerable<Li
 
         public IEnumerable<LibraryDependency> TransitiveDependencies { get; }
 
-        public bool Equals(CentralTransitiveDependencyGroup other)
+        public bool Equals(CentralTransitiveDependencyGroup? other)
         {
             if (other == null)
             {
@@ -52,7 +50,7 @@ public bool Equals(CentralTransitiveDependencyGroup other)
             return false;
         }
 
-        public override bool Equals(object obj)
+        public override bool Equals(object? obj)
         {
             return Equals(obj as CentralTransitiveDependencyGroup);
         }
diff --git a/src/NuGet.Core/NuGet.ProjectModel/CircularMemoryStream.cs b/src/NuGet.Core/NuGet.ProjectModel/CircularMemoryStream.cs
@@ -1,8 +1,6 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-#nullable disable
-
 using System;
 using System.IO;
 
@@ -15,7 +13,7 @@ internal sealed class CircularMemoryStream : MemoryStream
     {
         private readonly byte[] _buffer;
 
-        internal event EventHandler<ArraySegment<byte>> OnFlush;
+        internal event EventHandler<ArraySegment<byte>>? OnFlush;
 
         internal CircularMemoryStream(byte[] buffer) : base(buffer)
         {
diff --git a/src/NuGet.Core/NuGet.ProjectModel/FileFormatException.cs b/src/NuGet.Core/NuGet.ProjectModel/FileFormatException.cs
@@ -1,8 +1,6 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-#nullable disable
-
 using System;
 using System.Globalization;
 using Newtonsoft.Json;
@@ -22,7 +20,7 @@ public FileFormatException(string message, Exception innerException)
         {
         }
 
-        public string Path { get; private set; }
+        public string? Path { get; private set; }
         public int Line { get; private set; }
         public int Column { get; private set; }
 
diff --git a/src/NuGet.Core/NuGet.ProjectModel/HashObjectWriter.cs b/src/NuGet.Core/NuGet.ProjectModel/HashObjectWriter.cs
@@ -1,8 +1,6 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-#nullable disable
-
 using System;
 using System.Collections.Generic;
 using System.IO;
@@ -134,7 +132,7 @@ public void WriteNameValue(string name, bool value)
             _writer.WriteValue(value);
         }
 
-        public void WriteNameValue(string name, string value)
+        public void WriteNameValue(string name, string? value)
         {
             if (name == null)
             {
@@ -260,11 +258,11 @@ public void WriteArrayEnd()
             --_nestLevel;
         }
 
-        private void OnFlush(object sender, ArraySegment<byte> bytes)
+        private void OnFlush(object? sender, ArraySegment<byte> bytes)
         {
             if (bytes.Count > 0)
             {
-                _hashFunc.Update(bytes.Array, bytes.Offset, bytes.Count);
+                _hashFunc.Update(bytes.Array!, bytes.Offset, bytes.Count);
             }
         }
 
diff --git a/src/NuGet.Core/NuGet.ProjectModel/IExternalProjectReferenceProvider.cs b/src/NuGet.Core/NuGet.ProjectModel/IExternalProjectReferenceProvider.cs
@@ -1,15 +1,15 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-#nullable disable
-
+using System;
 using System.Collections.Generic;
 
 namespace NuGet.ProjectModel
 {
     /// <summary>
     /// Provides external project reference closures.
     /// </summary>
+    [Obsolete("This API is unused and will be removed in a future release.")]
     public interface IExternalProjectReferenceProvider
     {
         /// <summary>
diff --git a/src/NuGet.Core/NuGet.ProjectModel/JTokenExtensions.cs b/src/NuGet.Core/NuGet.ProjectModel/JTokenExtensions.cs
@@ -1,26 +1,26 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-#nullable disable
-
+using System;
 using System.Linq;
 using Newtonsoft.Json.Linq;
 
 namespace NuGet.ProjectModel
 {
+    [Obsolete("This class is unused and will be removed in a future release.")]
     public static class JTokenExtensions
     {
-        public static T[] ValueAsArray<T>(this JToken jToken)
+        public static T?[] ValueAsArray<T>(this JToken jToken)
         {
             return jToken.Select(a => a.Value<T>()).ToArray();
         }
 
-        public static T[] ValueAsArray<T>(this JToken jToken, string name)
+        public static T?[]? ValueAsArray<T>(this JToken jToken, string name)
         {
             return jToken?[name]?.ValueAsArray<T>();
         }
 
-        public static T GetValue<T>(this JToken token, string name)
+        public static T? GetValue<T>(this JToken token, string name)
         {
             if (token == null)
             {
diff --git a/src/NuGet.Core/NuGet.ProjectModel/PackageSpecUtility.cs b/src/NuGet.Core/NuGet.ProjectModel/PackageSpecUtility.cs
@@ -1,8 +1,6 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-#nullable disable
-
 using System;
 using NuGet.Versioning;
 
@@ -13,7 +11,7 @@ public static class PackageSpecUtility
         /// <summary>
         /// Apply a snapshot value.
         /// </summary>
-        public static NuGetVersion SpecifySnapshot(string version, string snapshotValue)
+        public static NuGetVersion SpecifySnapshot(string version, string? snapshotValue)
         {
             // Snapshots should be in the form 1.0.0-*, 1.0.0-beta-*, or 1.0.0-rc.*
             // Snapshots may not contain metadata such as 1.0.0+5.* or be stable versions such as 1.0.*
@@ -35,7 +33,7 @@ public static NuGetVersion SpecifySnapshot(string version, string snapshotValue)
         /// <summary>
         /// True if the string is a snapshot version.
         /// </summary>
-        public static bool IsSnapshotVersion(string version)
+        public static bool IsSnapshotVersion(string? version)
         {
             if (version != null
                 && version.EndsWith("*", StringComparison.Ordinal)
@@ -45,8 +43,7 @@ public static bool IsSnapshotVersion(string version)
                     || (version.EndsWith(".*", StringComparison.Ordinal))))
             {
                 // Verify the version is valid
-                NuGetVersion parsed = null;
-                return NuGetVersion.TryParse(version.Substring(0, version.Length - 2), out parsed);
+                return NuGetVersion.TryParse(version.Substring(0, version.Length - 2), out _);
             }
 
             return false;
diff --git a/src/NuGet.Core/NuGet.ProjectModel/PackagesConfigProjectRestoreMetadata.cs b/src/NuGet.Core/NuGet.ProjectModel/PackagesConfigProjectRestoreMetadata.cs
@@ -1,8 +1,6 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-#nullable disable
-
 using NuGet.Common;
 using NuGet.Shared;
 
@@ -13,12 +11,12 @@ public class PackagesConfigProjectRestoreMetadata : ProjectRestoreMetadata
         /// <summary>
         /// Full path to the packages.config file, if it exists. Only valid when ProjectStyle is PackagesConfig.
         /// </summary>
-        public string PackagesConfigPath { get; set; }
+        public string? PackagesConfigPath { get; set; }
 
         /// <summary>
         /// User packages repository path.
         /// </summary>
-        public string RepositoryPath { get; set; }
+        public string? RepositoryPath { get; set; }
 
         public override int GetHashCode()
         {
@@ -30,13 +28,18 @@ public override int GetHashCode()
             return hashCode.CombinedHash;
         }
 
-        public override bool Equals(object obj)
+        public override bool Equals(object? obj)
         {
             return Equals(obj as PackagesConfigProjectRestoreMetadata);
         }
 
-        public bool Equals(PackagesConfigProjectRestoreMetadata obj)
+        public bool Equals(PackagesConfigProjectRestoreMetadata? obj)
         {
+            if (obj == null)
+            {
+                return false;
+            }
+
             return base.Equals(obj) &&
                 PathUtility.GetStringComparerBasedOnOS().Equals(PackagesConfigPath, obj.PackagesConfigPath);
         }
diff --git a/src/NuGet.Core/NuGet.ProjectModel/ProjectFileDependencyGroup.cs b/src/NuGet.Core/NuGet.ProjectModel/ProjectFileDependencyGroup.cs
@@ -1,8 +1,6 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-#nullable disable
-
 using System;
 using System.Collections.Generic;
 using NuGet.Shared;
@@ -13,15 +11,15 @@ public class ProjectFileDependencyGroup : IEquatable<ProjectFileDependencyGroup>
     {
         public ProjectFileDependencyGroup(string frameworkName, IEnumerable<string> dependencies)
         {
-            FrameworkName = frameworkName;
-            Dependencies = dependencies;
+            FrameworkName = frameworkName ?? throw new ArgumentNullException(nameof(frameworkName));
+            Dependencies = dependencies ?? throw new ArgumentNullException(nameof(dependencies));
         }
 
         public string FrameworkName { get; }
 
         public IEnumerable<string> Dependencies { get; }
 
-        public bool Equals(ProjectFileDependencyGroup other)
+        public bool Equals(ProjectFileDependencyGroup? other)
         {
             if (other == null)
             {
@@ -46,7 +44,7 @@ public bool Equals(ProjectFileDependencyGroup other)
             return false;
         }
 
-        public override bool Equals(object obj)
+        public override bool Equals(object? obj)
         {
             return Equals(obj as ProjectFileDependencyGroup);
         }
diff --git a/src/NuGet.Core/NuGet.ProjectModel/ProjectRestoreMetadataFile.cs b/src/NuGet.Core/NuGet.ProjectModel/ProjectRestoreMetadataFile.cs
@@ -1,8 +1,6 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-#nullable disable
-
 using System;
 using NuGet.Shared;
 
@@ -38,7 +36,7 @@ public ProjectRestoreMetadataFile(string packagePath, string absolutePath)
             AbsolutePath = absolutePath;
         }
 
-        public bool Equals(ProjectRestoreMetadataFile other)
+        public bool Equals(ProjectRestoreMetadataFile? other)
         {
             if (ReferenceEquals(this, other))
             {
@@ -54,7 +52,7 @@ public bool Equals(ProjectRestoreMetadataFile other)
                 && StringComparer.Ordinal.Equals(AbsolutePath, other.AbsolutePath);
         }
 
-        public override bool Equals(object obj)
+        public override bool Equals(object? obj)
         {
             return Equals(obj as ProjectRestoreMetadataFile);
         }
@@ -74,9 +72,9 @@ public override string ToString()
             return PackagePath;
         }
 
-        public int CompareTo(ProjectRestoreMetadataFile other)
+        public int CompareTo(ProjectRestoreMetadataFile? other)
         {
-            return StringComparer.Ordinal.Compare(PackagePath, other.PackagePath);
+            return StringComparer.Ordinal.Compare(PackagePath, other?.PackagePath);
         }
 
         public ProjectRestoreMetadataFile Clone()
diff --git a/src/NuGet.Core/NuGet.ProjectModel/ProjectRestoreSettings.cs b/src/NuGet.Core/NuGet.ProjectModel/ProjectRestoreSettings.cs
@@ -1,8 +1,6 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-#nullable disable
-
 using NuGet.Shared;
 using NuGet.Versioning;
 
@@ -23,7 +21,7 @@ public class ProjectRestoreSettings
         /// Indicates the .NET SDK Version if any.
         /// In combination with SdkAnalysisLevel, it allows us to determine whether the analysis level is the default one or manually specified.
         /// </summary>
-        public NuGetVersion SdkVersion { get; set; }
+        public NuGetVersion? SdkVersion { get; set; }
 
         public ProjectRestoreSettings Clone()
         {
@@ -33,12 +31,12 @@ public ProjectRestoreSettings Clone()
             return clonedObject;
         }
 
-        public override bool Equals(object obj)
+        public override bool Equals(object? obj)
         {
             return Equals(obj as ProjectRestoreSettings);
         }
 
-        public bool Equals(ProjectRestoreSettings other)
+        public bool Equals(ProjectRestoreSettings? other)
         {
             if (other == null)
             {
diff --git a/src/NuGet.Core/NuGet.ProjectModel/PublicAPI.Shipped.txt b/src/NuGet.Core/NuGet.ProjectModel/PublicAPI.Shipped.txt
diff --git a/src/NuGet.Core/NuGet.ProjectModel/RestoreLockProperties.cs b/src/NuGet.Core/NuGet.ProjectModel/RestoreLockProperties.cs
diff --git a/src/NuGet.Core/NuGet.ProjectModel/ToolPathResolver.cs b/src/NuGet.Core/NuGet.ProjectModel/ToolPathResolver.cs
diff --git a/src/NuGet.Core/NuGet.ProjectModel/WarningProperties.cs b/src/NuGet.Core/NuGet.ProjectModel/WarningProperties.cs
diff --git a/test/NuGet.Core.Tests/NuGet.Commands.Test/DotnetCliToolTests.cs b/test/NuGet.Core.Tests/NuGet.Commands.Test/DotnetCliToolTests.cs
diff --git a/test/NuGet.Core.Tests/NuGet.Commands.Test/WarningPropertiesTests.cs b/test/NuGet.Core.Tests/NuGet.Commands.Test/WarningPropertiesTests.cs
diff --git a/test/NuGet.Core.Tests/NuGet.ProjectModel.Test/CentralTransitiveDependencyGroupTests.cs b/test/NuGet.Core.Tests/NuGet.ProjectModel.Test/CentralTransitiveDependencyGroupTests.cs

Original file line number	Diff line number	Diff line change
`@@ -91,7 +91,7 @@ public static bool IsTrueOrEmpty(string? value)`
`91`	`91`	`/// </summary>`
`92`	`92`	`/// <param name="s">A comma or semicolon delimited list of NuGet log codes.</param>`
`93`	`93`	`/// <returns>An <see cref="IList{T}" /> containing the <see cref="NuGetLogCode" /> values that were successfully parsed from the specified string.</returns>`
`94`		`- public static ImmutableArray<NuGetLogCode> GetNuGetLogCodes(string s)`
	`94`	`+ public static ImmutableArray<NuGetLogCode> GetNuGetLogCodes(string? s)`
`95`	`95`	`{`
`96`	`96`	`// The Split() method already checks for an empty string and returns Array.Empty<string>().`
`97`	`97`	`string[] split = MSBuildStringUtility.Split(s, ';', ',');`
Original file line number	Diff line number	Diff line change
`@@ -1,8 +1,6 @@`
`1`	`1`	`// Copyright (c) .NET Foundation. All rights reserved.`
`2`	`2`	`// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.`
`3`	`3`
`4`		`-#nullable disable`
`5`		`-`
`6`	`4`	`using System;`
`7`	`5`	`using System.Collections.Generic;`
`8`	`6`	`using NuGet.Frameworks;`
`@@ -32,7 +30,7 @@ public CentralTransitiveDependencyGroup(NuGetFramework framework, IEnumerable<Li`
`32`	`30`
`33`	`31`	`public IEnumerable<LibraryDependency> TransitiveDependencies { get; }`
`34`	`32`
`35`		`- public bool Equals(CentralTransitiveDependencyGroup other)`
	`33`	`+ public bool Equals(CentralTransitiveDependencyGroup? other)`
`36`	`34`	`{`
`37`	`35`	`if (other == null)`
`38`	`36`	`{`
`@@ -52,7 +50,7 @@ public bool Equals(CentralTransitiveDependencyGroup other)`
`52`	`50`	`return false;`
`53`	`51`	`}`
`54`	`52`
`55`		`- public override bool Equals(object obj)`
	`53`	`+ public override bool Equals(object? obj)`
`56`	`54`	`{`
`57`	`55`	`return Equals(obj as CentralTransitiveDependencyGroup);`
`58`	`56`	`}`
Original file line number	Diff line number	Diff line change
`@@ -1,26 +1,26 @@`
`1`	`1`	`// Copyright (c) .NET Foundation. All rights reserved.`
`2`	`2`	`// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.`
`3`	`3`
`4`		`-#nullable disable`
`5`		`-`
	`4`	`+using System;`
`6`	`5`	`using System.Linq;`
`7`	`6`	`using Newtonsoft.Json.Linq;`
`8`	`7`
`9`	`8`	`namespace NuGet.ProjectModel`
`10`	`9`	`{`
	`10`	`+ [Obsolete("This class is unused and will be removed in a future release.")]`
`11`	`11`	`public static class JTokenExtensions`
`12`	`12`	`{`
`13`		`- public static T[] ValueAsArray<T>(this JToken jToken)`
	`13`	`+ public static T?[] ValueAsArray<T>(this JToken jToken)`
`14`	`14`	`{`
`15`	`15`	`return jToken.Select(a => a.Value<T>()).ToArray();`
`16`	`16`	`}`
`17`	`17`
`18`		`- public static T[] ValueAsArray<T>(this JToken jToken, string name)`
	`18`	`+ public static T?[]? ValueAsArray<T>(this JToken jToken, string name)`
`19`	`19`	`{`
`20`	`20`	`return jToken?[name]?.ValueAsArray<T>();`
`21`	`21`	`}`
`22`	`22`
`23`		`- public static T GetValue<T>(this JToken token, string name)`
	`23`	`+ public static T? GetValue<T>(this JToken token, string name)`
`24`	`24`	`{`
`25`	`25`	`if (token == null)`
`26`	`26`	`{`