Auto-remove manual NuGet.* version pins on future major versions

src/Fallout.Migrate/Migration.cs

@@ -27,6 +27,8 @@ internal sealed class Migration(AbsolutePath rootDirectory, bool dryRun, TextWri
         new VerifyBuildTargetFrameworkStep(),
         new ConfirmMigrationStep(),
         new RewriteCsprojsStep(),
+        new RemoveNugetFrameworkPinStep(),
+        new RemoveRelatedNugetPinsStep(),
         new BumpDotNetVersionStep(),
         new RewriteCsFilesStep(),
         new RewriteBootstrapScriptsStep(),

src/Fallout.Migrate/Steps/RemoveNugetFrameworkPinStep.cs

@@ -0,0 +1,39 @@
+using System.Text.RegularExpressions;
+using System.Threading.Tasks;
+using Fallout.Migrate.Common;
+
+namespace Fallout.Migrate.Steps;
+
+/// <summary>
+/// Removes explicit <c>NuGet.Framework</c>, <c>NuGet.Protocol</c>, <c>NuGet.Packaging</c>, and
+/// <c>NuGet.Resolver</c> package pins from project files. The pins are no longer needed.
+/// </summary>
+internal sealed class RemoveNugetFrameworkPinStep : IMigrationStep
+{
+    private static readonly Regex explicitPinPattern = new(
+        @"^[ \t]*<PackageReference\s+(?=[^>\r\n]*\bInclude=""NuGet\.Frameworks"")(?=[^>\r\n]*\bVersion=""[^""]+"")[^>\r\n]*/>[ \t]*\r?\n?",
+        RegexOptions.Compiled | RegexOptions.Multiline);
+
+    /// <inheritdoc />
+    public Task ExecuteAsync(MigrationContext context, Summary summary)
+    {
+        foreach (var path in MigrationFileOperations.EnumerateFiles(context.RootDirectory, "*.csproj"))
+        {
+            MigrationFileOperations.ApplyRewrite(context, path, Rewrite, summary);
+        }
+
+        return Task.CompletedTask;
+    }
+
+    private static RewriteResult Rewrite(string original)
+    {
+        var edits = 0;
+        var content = explicitPinPattern.Replace(original, _ =>
+        {
+            edits++;
+            return string.Empty;
+        });
+
+        return new RewriteResult(content, edits);
+    }
+}

src/Fallout.Migrate/Steps/RemoveRelatedNugetPinsStep.cs

@@ -0,0 +1,56 @@
+using System.Globalization;
+using System.Text.RegularExpressions;
+using System.Threading.Tasks;
+using Fallout.Migrate.Common;
+
+namespace Fallout.Migrate.Steps;
+
+/// <summary>
+/// Removes explicit <c>NuGet.Protocol</c>, <c>NuGet.Packaging</c>, and <c>NuGet.Resolver</c>
+/// package pins from project files when migrating to Fallout 11 or later.
+/// </summary>
+internal sealed class RemoveRelatedNugetPinsStep : IMigrationStep
+{
+    private const int MinimumFalloutMajor = 11;
+
+    private static readonly Regex explicitPinPattern = new(
+        @"^[ \t]*<PackageReference\s+(?=[^>\r\n]*\bInclude=""NuGet\.(?:Protocol|Packaging|Resolver)"")(?=[^>\r\n]*\bVersion=""[^""]+"")[^>\r\n]*/>[ \t]*\r?\n?",
+        RegexOptions.Compiled | RegexOptions.Multiline);
+
+    /// <inheritdoc />
+    public Task ExecuteAsync(MigrationContext context, Summary summary)
+    {
+        if (!RunsFor(context.FalloutVersion))
+        {
+            return Task.CompletedTask;
+        }
+
+        foreach (var path in MigrationFileOperations.EnumerateFiles(context.RootDirectory, "*.csproj"))
+        {
+            MigrationFileOperations.ApplyRewrite(context, path, Rewrite, summary);
+        }
+
+        return Task.CompletedTask;
+    }
+
+    private static bool RunsFor(string version)
+    {
+        int separatorIndex = version?.IndexOf('.') ?? -1;
+        string majorSegment = separatorIndex == -1 ? version : version[..separatorIndex];
+
+        return int.TryParse(majorSegment, NumberStyles.None, CultureInfo.InvariantCulture, out int major) &&
+               major >= MinimumFalloutMajor;
+    }
+
+    private static RewriteResult Rewrite(string original)
+    {
+        var edits = 0;
+        var content = explicitPinPattern.Replace(original, _ =>
+        {
+            edits++;
+            return string.Empty;
+        });
+
+        return new RewriteResult(content, edits);
+    }
+}

tests/Fallout.Migrate.Specs/RemoveNugetFrameworkPinStepSpecs.cs

@@ -0,0 +1,108 @@
+using System;
+using System.IO;
+using System.Threading.Tasks;
+using Fallout.Common.IO;
+using Fallout.Migrate.Common;
+using Fallout.Migrate.Steps;
+using FluentAssertions;
+using Xunit;
+
+namespace Fallout.Migrate.Specs;
+
+public class RemoveNugetFrameworkPinStepSpecs : IDisposable
+{
+    private readonly AbsolutePath tempDirectory;
+    private readonly MigrationContext context;
+    private readonly Summary summary = new();
+
+    public RemoveNugetFrameworkPinStepSpecs()
+    {
+        tempDirectory = AbsolutePath.Temp("fallout-remove-nuget-framework-pin");
+        context = new MigrationContext(tempDirectory, dryRun: false, TextWriter.Null);
+    }
+
+    [Fact]
+    public async Task Explicit_nuget_framework_pin_is_removed()
+    {
+        // Arrange
+        var project = tempDirectory / "Library.csproj";
+        project.WriteAllText(
+            """
+            <Project Sdk="Microsoft.NET.Sdk">
+              <ItemGroup>
+                <PackageReference Version="7.9.0" PrivateAssets="all" Include="NuGet.Frameworks" />
+                <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
+              </ItemGroup>
+            </Project>
+            """, eofLineBreak: false);
+
+        // Act
+        await new RemoveNugetFrameworkPinStep().ExecuteAsync(context, summary);
+
+        // Assert
+        project.ReadAllText().Should().Be(
+            """
+            <Project Sdk="Microsoft.NET.Sdk">
+              <ItemGroup>
+                <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
+              </ItemGroup>
+            </Project>
+            """);
+
+        summary.FilesChanged.Should().Be(1);
+        summary.EditCount.Should().Be(1);
+    }
+
+    [Fact]
+    public async Task Nuget_framework_reference_without_version_is_left_unchanged()
+    {
+        // Arrange
+        var project = tempDirectory / "Library.csproj";
+        const string input =
+            """
+            <Project Sdk="Microsoft.NET.Sdk">
+              <ItemGroup>
+                <PackageReference Include="NuGet.Frameworks" />
+              </ItemGroup>
+            </Project>
+            """;
+
+        project.WriteAllText(input, eofLineBreak: false);
+
+        // Act
+        await new RemoveNugetFrameworkPinStep().ExecuteAsync(context, summary);
+
+        // Assert
+        project.ReadAllText().Should().Be(input);
+        summary.EditCount.Should().Be(0);
+    }
+
+    [Fact]
+    public async Task Missing_nuget_framework_pin_is_left_unchanged()
+    {
+        // Arrange
+        var project = tempDirectory / "build" / "_build.csproj";
+        const string input =
+            """
+            <Project Sdk="Microsoft.NET.Sdk">
+              <PropertyGroup>
+                <TargetFramework>net10.0</TargetFramework>
+              </PropertyGroup>
+            </Project>
+            """;
+
+        project.WriteAllText(input, eofLineBreak: false);
+
+        // Act
+        await new RemoveNugetFrameworkPinStep().ExecuteAsync(context, summary);
+
+        // Assert
+        project.ReadAllText().Should().Be(input);
+        summary.EditCount.Should().Be(0);
+    }
+
+    public void Dispose()
+    {
+        tempDirectory.DeleteDirectory();
+    }
+}

tests/Fallout.Migrate.Specs/RemoveRelatedNugetPinsStepSpecs.cs

@@ -0,0 +1,94 @@
+using System;
+using System.IO;
+using System.Threading.Tasks;
+using Fallout.Common.IO;
+using Fallout.Migrate.Common;
+using Fallout.Migrate.Steps;
+using FluentAssertions;
+using Xunit;
+
+namespace Fallout.Migrate.Specs;
+
+public class RemoveRelatedNugetPinsStepSpecs : IDisposable
+{
+    private readonly AbsolutePath tempDirectory;
+    private readonly Summary summary = new();
+
+    public RemoveRelatedNugetPinsStepSpecs()
+    {
+        tempDirectory = AbsolutePath.Temp("fallout-remove-related-nuget-pins");
+    }
+
+    [Theory]
+    [InlineData("NuGet.Protocol", "11.0.0")]
+    [InlineData("NuGet.Packaging", "11.0.0-preview.1")]
+    [InlineData("NuGet.Resolver", "12.0.0")]
+    public async Task Explicit_related_nuget_pin_is_removed_for_v11_or_later(
+        string packageName,
+        string falloutVersion)
+    {
+        // Arrange
+        var project = tempDirectory / "Library.csproj";
+        project.WriteAllText(
+            $"""
+            <Project Sdk="Microsoft.NET.Sdk">
+              <ItemGroup>
+                <PackageReference Include="{packageName}" Version="7.9.0" />
+              </ItemGroup>
+            </Project>
+            """, eofLineBreak: false);
+        var context = CreateContext(falloutVersion);
+
+        // Act
+        await new RemoveRelatedNugetPinsStep().ExecuteAsync(context, summary);
+
+        // Assert
+        project.ReadAllText().Should().Be(
+            """
+            <Project Sdk="Microsoft.NET.Sdk">
+              <ItemGroup>
+              </ItemGroup>
+            </Project>
+            """);
+        summary.FilesChanged.Should().Be(1);
+        summary.EditCount.Should().Be(1);
+    }
+
+    [Theory]
+    [InlineData("10.9.0")]
+    [InlineData(null)]
+    public async Task Explicit_related_nuget_pin_is_left_unchanged_before_v11(string falloutVersion)
+    {
+        // Arrange
+        var project = tempDirectory / "Library.csproj";
+        const string input =
+            """
+            <Project Sdk="Microsoft.NET.Sdk">
+              <ItemGroup>
+                <PackageReference Include="NuGet.Protocol" Version="7.9.0" />
+              </ItemGroup>
+            </Project>
+            """;
+
+        project.WriteAllText(input, eofLineBreak: false);
+        var context = CreateContext(falloutVersion);
+
+        // Act
+        await new RemoveRelatedNugetPinsStep().ExecuteAsync(context, summary);
+
+        // Assert
+        project.ReadAllText().Should().Be(input);
+        summary.EditCount.Should().Be(0);
+    }
+
+    private MigrationContext CreateContext(string falloutVersion) =>
+        new(tempDirectory, dryRun: false, TextWriter.Null)
+        {
+            FalloutVersion = falloutVersion
+        };
+
+    public void Dispose()
+    {
+        tempDirectory.DeleteDirectory();
+    }
+}