Modernize to .NET 8: add SDK-style projects, CI and NuGet publish workflow

.github/workflows/ci.yml

@@ -0,0 +1,31 @@
+name: CI
+
+on:
+  push:
+    branches: [ master, main, dev ]
+  pull_request:
+
+jobs:
+  build-dotnet8:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup .NET SDK
+        uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: 8.0.x
+
+      - name: Build modern SDK-style projects (v2)
+        run: |
+          dotnet build src/FlatFile.Core.Modern/FlatFile.Core.Modern.csproj -c Release
+          dotnet build src/FlatFile.Core.Attributes.Modern/FlatFile.Core.Attributes.Modern.csproj -c Release
+          dotnet build src/FlatFile.Delimited.Modern/FlatFile.Delimited.Modern.csproj -c Release
+          dotnet build src/FlatFile.FixedLength.Modern/FlatFile.FixedLength.Modern.csproj -c Release
+          dotnet build src/FlatFile.Delimited.Attributes.Modern/FlatFile.Delimited.Attributes.Modern.csproj -c Release
+          dotnet build src/FlatFile.FixedLength.Attributes.Modern/FlatFile.FixedLength.Attributes.Modern.csproj -c Release
+          dotnet build tests/FlatFile.Modern.Tests/FlatFile.Modern.Tests.csproj -c Release
+
+      - name: Run modern test suite
+        run: dotnet test tests/FlatFile.Modern.Tests/FlatFile.Modern.Tests.csproj -c Release --no-build

.github/workflows/publish-nuget.yml

@@ -0,0 +1,48 @@
+name: Publish NuGet (v2)
+
+on:
+  push:
+    branches: [ master ]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    env:
+      NUGET_API_KEY: ${{ secrets.NUGET_API_KEY }}
+      PACKAGE_VERSION: 2.0.${{ github.run_number }}
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup .NET SDK
+        uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: 8.0.x
+
+      - name: Validate NuGet API key is configured
+        run: |
+          if [ -z "$NUGET_API_KEY" ]; then
+            echo "NUGET_API_KEY secret is not configured." >&2
+            exit 1
+          fi
+
+      - name: Pack v2 packages
+        run: |
+          mkdir -p artifacts/packages
+          dotnet pack src/FlatFile.Core.Modern/FlatFile.Core.Modern.csproj -c Release -o artifacts/packages /p:Version=$PACKAGE_VERSION
+          dotnet pack src/FlatFile.Core.Attributes.Modern/FlatFile.Core.Attributes.Modern.csproj -c Release -o artifacts/packages /p:Version=$PACKAGE_VERSION
+          dotnet pack src/FlatFile.Delimited.Modern/FlatFile.Delimited.Modern.csproj -c Release -o artifacts/packages /p:Version=$PACKAGE_VERSION
+          dotnet pack src/FlatFile.FixedLength.Modern/FlatFile.FixedLength.Modern.csproj -c Release -o artifacts/packages /p:Version=$PACKAGE_VERSION
+          dotnet pack src/FlatFile.Delimited.Attributes.Modern/FlatFile.Delimited.Attributes.Modern.csproj -c Release -o artifacts/packages /p:Version=$PACKAGE_VERSION
+          dotnet pack src/FlatFile.FixedLength.Attributes.Modern/FlatFile.FixedLength.Attributes.Modern.csproj -c Release -o artifacts/packages /p:Version=$PACKAGE_VERSION
+
+      - name: Publish packages to NuGet
+        run: |
+          dotnet nuget push "artifacts/packages/*.nupkg" \
+            --api-key "$NUGET_API_KEY" \
+            --source https://api.nuget.org/v3/index.json \
+            --skip-duplicate

README.md

@@ -4,6 +4,44 @@ FlatFile
 
 FlatFile is a library to work with flat files (work up-to 100 times faster then [FileHelpers](https://www.nuget.org/packages/FileHelpers/2.0.0))
 
+
+## Modernization status
+
+- 🚨 **v2 breaking change**: dropped legacy .NET Framework targets (`net35`-`net48`) and old build pipeline.
+- ✅ Modernized runtime support to **.NET 8** only via SDK-style projects.
+- ✅ CI now builds modern projects with `dotnet build` on GitHub Actions.
+
+### Modern .NET support
+
+Active projects:
+
+- `src/FlatFile.Core.Modern`
+- `src/FlatFile.Core.Attributes.Modern`
+- `src/FlatFile.Delimited.Modern`
+- `src/FlatFile.FixedLength.Modern`
+- `src/FlatFile.Delimited.Attributes.Modern`
+- `src/FlatFile.FixedLength.Attributes.Modern`
+
+All of them target `net8.0` and carry package/assembly version `2.0.0`.
+
+### Runtime enhancements (v2)
+
+Recent runtime-focused updates for modern .NET:
+
+- Faster reflection activation path via compiled constructor delegates and concurrent caches.
+- Improved string-to-type conversion using cached `TypeConverter` instances and invariant-culture conversion semantics.
+- Reduced allocations in parsing paths (for example, char-based trim overloads and span-based quote detection in delimited parser).
+
+### NuGet publishing from GitHub
+
+When changes are merged to `master`, GitHub Actions can publish v2 packages automatically using `.github/workflows/publish-nuget.yml`.
+
+Required repository secret:
+
+- `NUGET_API_KEY`: NuGet.org API key with push permission for FlatFile packages.
+
+The publish workflow packs all `*.Modern` projects and pushes resulting `.nupkg` files to NuGet (`--skip-duplicate`).
+
 ### Installing FlatFile
 
 #### Installing all packages

assets/psake-common.ps1

@@ -20,43 +20,43 @@ Properties {
     ### Project information
     $solution_path = "$src_dir\$solution"
 	$sharedAssemblyInfo = "$src_dir\SharedAssemblyInfo.cs"
-    $config = "Release"    
-	$frameworks = @("NET35", "NET40", "NET45")
+    $config = "Release"
+    $modern_projects = @(
+        "$src_dir\FlatFile.Core.Modern\FlatFile.Core.Modern.csproj",
+        "$src_dir\FlatFile.Core.Attributes.Modern\FlatFile.Core.Attributes.Modern.csproj",
+        "$src_dir\FlatFile.Delimited.Modern\FlatFile.Delimited.Modern.csproj",
+        "$src_dir\FlatFile.FixedLength.Modern\FlatFile.FixedLength.Modern.csproj",
+        "$src_dir\FlatFile.Delimited.Attributes.Modern\FlatFile.Delimited.Attributes.Modern.csproj",
+        "$src_dir\FlatFile.FixedLength.Attributes.Modern\FlatFile.FixedLength.Attributes.Modern.csproj"
+    )
 
     ### Files
     $releaseNotes = "$base_dir\ChangeLog.md"
 }
 
 ## Tasks
 
-Task Restore -Description "Restore NuGet packages for solution." {
-    "Restoring NuGet packages for '$solution_path'..."
-    Exec { .$nuget restore $solution_path }
+Task Restore -Description "Restore .NET packages for modern projects." {
+    foreach ($project in $modern_projects) {
+        "Restoring '$project'..."
+        Exec { dotnet restore $project }
+    }
 }
 
 Task Clean -Description "Clean up build and project folders." {
     Clean-Directory $build_dir
 
-    if ($solution) {
-        "Cleaning up '$solution'..."
-
-		foreach ($framework in $frameworks) {
-			Exec { msbuild $solution_path /target:Clean /nologo /verbosity:minimal /p:Framework=$framework}
-		}
+    foreach ($project in $modern_projects) {
+        "Cleaning '$project'..."
+        Exec { dotnet clean $project -c $config }
     }
 }
 
-Task Compile -Depends Clean, Restore -Description "Compile all the projects in a solution." {
-    "Compiling '$solution'..."
-
-    $extra = $null
-    if ($appVeyor) {
-        $extra = "/logger:C:\Program Files\AppVeyor\BuildAgent\Appveyor.MSBuildLogger.dll"
+Task Compile -Depends Clean, Restore -Description "Compile all modern SDK-style projects." {
+    foreach ($project in $modern_projects) {
+        "Compiling '$project'..."
+        Exec { dotnet build $project -c $config --no-restore }
     }
-
-	foreach ($framework in $frameworks) {
-		Exec { msbuild $solution_path /p:"Configuration=$config;Framework=$framework" /nologo /verbosity:minimal $extra }
-	}
 }
 
 ### Pack functions

docs/modernization-plan.md

@@ -0,0 +1,48 @@
+# FlatFile modernization plan
+
+## Current direction (v2)
+
+This repository now follows a **modern-only** strategy:
+
+1. Legacy .NET Framework build matrix was removed from CI.
+2. SDK-style projects under `*.Modern` are the active build path.
+3. Active target is `net8.0` with version `2.0.0` (breaking major release).
+
+## Why
+
+The previous mixed strategy (legacy + modern) produced unstable CI and unnecessary maintenance overhead.
+A major-version reset enables simpler tooling, faster builds, and a clear support policy.
+
+## Next steps
+
+- Publish v2 packages from modern projects (`dotnet pack`).
+- Add analyzers and nullable annotations incrementally.
+- Add dedicated test projects targeting `net8.0`.
+
+
+## CI/CD publishing
+
+- `.github/workflows/publish-nuget.yml` publishes NuGet packages on pushes to `master`.
+- Configure repository secret `NUGET_API_KEY` before enabling release merges.
+- Package versions are generated as `2.0.<run_number>` in CI.
+
+
+## Implemented performance updates
+
+- Replaced reflection activation lock+`DynamicInvoke` path with concurrent cached compiled factories.
+- Updated conversion pipeline to use converter caching and invariant-culture conversion semantics.
+- Applied small parser allocation improvements (`TrimStart/TrimEnd(char)`, span-based quote prefix checks).
+
+
+## Modern tests
+
+- Added `tests/FlatFile.Modern.Tests` (xUnit, net8.0).
+- CI now runs `dotnet test` for the modern test suite.
+
+
+## Span/Memory guidelines used
+
+- Use `ReadOnlySpan<char>` for scanning/tokenization (delimiter/quote detection) where data remains in-memory and does not need ownership transfer.
+- Use `Memory<T>` only when data must survive async boundaries; prefer `Span<T>`/`ReadOnlySpan<T>` in synchronous hot paths.
+- Avoid premature `Substring`/`string.Format` allocations in line build/parse loops.
+- Keep API compatibility: introduce span optimizations internally first, then expose span APIs in a dedicated v2+ surface when needed.

src/Directory.Build.props

@@ -0,0 +1,17 @@
+<Project>
+  <PropertyGroup Condition="$([System.String]::Copy('$(MSBuildProjectName)').Contains('.Modern'))">
+    <IsPackable>true</IsPackable>
+    <PackageLicenseExpression>MIT</PackageLicenseExpression>
+    <Authors>forcewake</Authors>
+    <Company>Pavel Nasovich</Company>
+    <Description>FlatFile library for high-performance fixed-length and delimited file processing.</Description>
+    <PackageProjectUrl>https://github.com/forcewake/FlatFile</PackageProjectUrl>
+    <RepositoryUrl>https://github.com/forcewake/FlatFile</RepositoryUrl>
+    <RepositoryType>git</RepositoryType>
+    <PackageReadmeFile>README.md</PackageReadmeFile>
+  </PropertyGroup>
+
+  <ItemGroup Condition="$([System.String]::Copy('$(MSBuildProjectName)').Contains('.Modern'))">
+    <None Include="$(MSBuildThisFileDirectory)..\README.md" Pack="true" PackagePath="\" Link="README.md" />
+  </ItemGroup>
+</Project>

src/FlatFile.Benchmark/FlatFile.Benchmark.csproj

@@ -31,6 +31,63 @@
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
+
+
+  <PropertyGroup Condition=" '$(Framework)' == 'NET451' ">
+    <TargetFrameworkVersion>v4.5.1</TargetFrameworkVersion>
+    <PlatformTarget>AnyCPU</PlatformTarget>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Framework)' == 'NET452' ">
+    <TargetFrameworkVersion>v4.5.2</TargetFrameworkVersion>
+    <PlatformTarget>AnyCPU</PlatformTarget>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Framework)' == 'NET46' ">
+    <TargetFrameworkVersion>v4.6</TargetFrameworkVersion>
+    <PlatformTarget>AnyCPU</PlatformTarget>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Framework)' == 'NET461' ">
+    <TargetFrameworkVersion>v4.6.1</TargetFrameworkVersion>
+    <PlatformTarget>AnyCPU</PlatformTarget>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Framework)' == 'NET462' ">
+    <TargetFrameworkVersion>v4.6.2</TargetFrameworkVersion>
+    <PlatformTarget>AnyCPU</PlatformTarget>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Framework)' == 'NET47' ">
+    <TargetFrameworkVersion>v4.7</TargetFrameworkVersion>
+    <PlatformTarget>AnyCPU</PlatformTarget>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Framework)' == 'NET471' ">
+    <TargetFrameworkVersion>v4.7.1</TargetFrameworkVersion>
+    <PlatformTarget>AnyCPU</PlatformTarget>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Framework)' == 'NET472' ">
+    <TargetFrameworkVersion>v4.7.2</TargetFrameworkVersion>
+    <PlatformTarget>AnyCPU</PlatformTarget>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Framework)' == 'NET48' And '$(Configuration)|$(Platform)' == 'Debug|AnyCPU'">
+    <TargetFrameworkVersion>v4.8</TargetFrameworkVersion>
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>bin\$(Configuration)\$(Framework)\</OutputPath>
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Framework)' == 'NET48' And '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <TargetFrameworkVersion>v4.8</TargetFrameworkVersion>
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugType>pdbonly</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>bin\$(Configuration)\$(Framework)\</OutputPath>
+    <DefineConstants>TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+    <DocumentationFile>bin\$(Configuration)\$(Framework)\FlatFile.Benchmark.XML</DocumentationFile>
+  </PropertyGroup>
+
   <ItemGroup>
     <Reference Include="BenchmarkIt">
       <HintPath>..\packages\Benchmark.It.1.2.0\lib\BenchmarkIt.dll</HintPath>

src/FlatFile.Core.Attributes.Modern/FlatFile.Core.Attributes.Modern.csproj

@@ -0,0 +1,22 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <RootNamespace>FlatFile.Core.Attributes</RootNamespace>
+    <AssemblyName>FlatFile.Core.Attributes</AssemblyName>
+    <GenerateAssemblyInfo>false</GenerateAssemblyInfo>
+    <LangVersion>latest</LangVersion>
+    <Nullable>disable</Nullable>
+    <Deterministic>true</Deterministic>
+    <Version>2.0.0</Version>
+    <AssemblyVersion>2.0.0.0</AssemblyVersion>
+    <FileVersion>2.0.0.0</FileVersion>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Include="../FlatFile.Core.Attributes/**/*.cs" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="../FlatFile.Core.Modern/FlatFile.Core.Modern.csproj" />
+  </ItemGroup>
+</Project>