Add support C# 8 nullable reference types

appveyor.yml

@@ -2,14 +2,14 @@ version: '{build}'
 skip_tags: true
 image:
   - Visual Studio 2019
-  - Ubuntu1804
+  - Ubuntu
 build_script:
 - ps: ./Build.ps1
 for:
 -
   matrix:
     only:
-      - image: Ubuntu1804
+      - image: Ubuntu
   build_script:
     - sh build.sh
 test: off

example/Sample/Sample.csproj

@@ -1,7 +1,9 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp2.0;net47</TargetFrameworks>
+    <TargetFrameworks>net48;net5.0</TargetFrameworks>
+    <LangVersion>8.0</LangVersion>
+    <Nullable>enable</Nullable>
     <AssemblyName>Sample</AssemblyName>
     <OutputType>Exe</OutputType>
     <PackageId>Sample</PackageId>
@@ -12,10 +14,5 @@
     <ProjectReference Include="..\..\src\Serilog.Sinks.File\Serilog.Sinks.File.csproj" />
   </ItemGroup>
 
-  <ItemGroup Condition=" '$(TargetFramework)' == 'net47' ">
-    <Reference Include="System" />
-    <Reference Include="Microsoft.CSharp" />
-  </ItemGroup>
-
 </Project>
 

src/Serilog.Sinks.File/FileLoggerConfigurationExtensions.cs

@@ -253,17 +253,17 @@ public static LoggerConfiguration File(
             string path,
             LogEventLevel restrictedToMinimumLevel = LevelAlias.Minimum,
             string outputTemplate = DefaultOutputTemplate,
-            IFormatProvider formatProvider = null,
+            IFormatProvider? formatProvider = null,
             long? fileSizeLimitBytes = DefaultFileSizeLimitBytes,
-            LoggingLevelSwitch levelSwitch = null,
+            LoggingLevelSwitch? levelSwitch = null,
             bool buffered = false,
             bool shared = false,
             TimeSpan? flushToDiskInterval = null,
             RollingInterval rollingInterval = RollingInterval.Infinite,
             bool rollOnFileSizeLimit = false,
             int? retainedFileCountLimit = DefaultRetainedFileCountLimit,
-            Encoding encoding = null,
-            FileLifecycleHooks hooks = null,
+            Encoding? encoding = null,
+            FileLifecycleHooks? hooks = null,
             TimeSpan? retainedFileTimeLimit = null)
         {
             if (sinkConfiguration == null) throw new ArgumentNullException(nameof(sinkConfiguration));
@@ -324,15 +324,15 @@ public static LoggerConfiguration File(
             string path,
             LogEventLevel restrictedToMinimumLevel = LevelAlias.Minimum,
             long? fileSizeLimitBytes = DefaultFileSizeLimitBytes,
-            LoggingLevelSwitch levelSwitch = null,
+            LoggingLevelSwitch? levelSwitch = null,
             bool buffered = false,
             bool shared = false,
             TimeSpan? flushToDiskInterval = null,
             RollingInterval rollingInterval = RollingInterval.Infinite,
             bool rollOnFileSizeLimit = false,
             int? retainedFileCountLimit = DefaultRetainedFileCountLimit,
-            Encoding encoding = null,
-            FileLifecycleHooks hooks = null,
+            Encoding? encoding = null,
+            FileLifecycleHooks? hooks = null,
             TimeSpan? retainedFileTimeLimit = null)
         {
             if (sinkConfiguration == null) throw new ArgumentNullException(nameof(sinkConfiguration));
@@ -443,10 +443,10 @@ public static LoggerConfiguration File(
             string path,
             LogEventLevel restrictedToMinimumLevel = LevelAlias.Minimum,
             string outputTemplate = DefaultOutputTemplate,
-            IFormatProvider formatProvider = null,
-            LoggingLevelSwitch levelSwitch = null,
-            Encoding encoding = null,
-            FileLifecycleHooks hooks = null)
+            IFormatProvider? formatProvider = null,
+            LoggingLevelSwitch? levelSwitch = null,
+            Encoding? encoding = null,
+            FileLifecycleHooks? hooks = null)
         {
             if (sinkConfiguration == null) throw new ArgumentNullException(nameof(sinkConfiguration));
             if (path == null) throw new ArgumentNullException(nameof(path));
@@ -487,9 +487,9 @@ public static LoggerConfiguration File(
             ITextFormatter formatter,
             string path,
             LogEventLevel restrictedToMinimumLevel = LevelAlias.Minimum,
-            LoggingLevelSwitch levelSwitch = null,
-            Encoding encoding = null,
-            FileLifecycleHooks hooks = null)
+            LoggingLevelSwitch? levelSwitch = null,
+            Encoding? encoding = null,
+            FileLifecycleHooks? hooks = null)
         {
             if (sinkConfiguration == null) throw new ArgumentNullException(nameof(sinkConfiguration));
             if (formatter == null) throw new ArgumentNullException(nameof(formatter));
@@ -500,21 +500,21 @@ public static LoggerConfiguration File(
         }
 
         static LoggerConfiguration ConfigureFile(
-            this Func<ILogEventSink, LogEventLevel, LoggingLevelSwitch, LoggerConfiguration> addSink,
+            this Func<ILogEventSink, LogEventLevel, LoggingLevelSwitch?, LoggerConfiguration> addSink,
             ITextFormatter formatter,
             string path,
             LogEventLevel restrictedToMinimumLevel,
             long? fileSizeLimitBytes,
-            LoggingLevelSwitch levelSwitch,
+            LoggingLevelSwitch? levelSwitch,
             bool buffered,
             bool propagateExceptions,
             bool shared,
             TimeSpan? flushToDiskInterval,
-            Encoding encoding,
+            Encoding? encoding,
             RollingInterval rollingInterval,
             bool rollOnFileSizeLimit,
             int? retainedFileCountLimit,
-            FileLifecycleHooks hooks,
+            FileLifecycleHooks? hooks,
             TimeSpan? retainedFileTimeLimit)
         {
             if (addSink == null) throw new ArgumentNullException(nameof(addSink));

src/Serilog.Sinks.File/Properties/AssemblyInfo.cs

@@ -2,8 +2,6 @@
 using System.Reflection;
 using System.Runtime.CompilerServices;
 
-[assembly: AssemblyVersion("2.0.0.0")]
-
 [assembly: CLSCompliant(true)]
 
 [assembly: InternalsVisibleTo("Serilog.Sinks.File.Tests, PublicKey=" +

src/Serilog.Sinks.File/Serilog.Sinks.File.csproj

@@ -4,7 +4,9 @@
     <Description>Write Serilog events to text files in plain or JSON format.</Description>
     <VersionPrefix>5.0.0</VersionPrefix>
     <Authors>Serilog Contributors</Authors>
-    <TargetFrameworks>net45;netstandard1.3;netstandard2.0;netcoreapp3.0</TargetFrameworks>
+    <TargetFrameworks>net45;netstandard1.3;netstandard2.0;netstandard2.1</TargetFrameworks>
+    <LangVersion>8.0</LangVersion>
+    <Nullable>enable</Nullable>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <AssemblyOriginatorKeyFile>../../assets/Serilog.snk</AssemblyOriginatorKeyFile>
     <SignAssembly>true</SignAssembly>
@@ -16,7 +18,6 @@
     <PackageLicenseExpression>Apache-2.0</PackageLicenseExpression>
     <RepositoryUrl>https://github.com/serilog/serilog-sinks-file</RepositoryUrl>
     <RepositoryType>git</RepositoryType>
-    <GenerateAssemblyVersionAttribute>false</GenerateAssemblyVersionAttribute>
     <RootNamespace>Serilog</RootNamespace>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
     <DisableImplicitFrameworkReferences Condition=" '$(TargetFramework)' == 'netstandard1.3' ">true</DisableImplicitFrameworkReferences>
@@ -34,26 +35,12 @@
     <DefineConstants>$(DefineConstants);ATOMIC_APPEND;HRESULTS</DefineConstants>
   </PropertyGroup>
 
-  <PropertyGroup Condition=" '$(TargetFramework)' == 'netstandard1.3' ">
+  <PropertyGroup Condition=" '$(TargetFramework)' != 'net45'  ">
     <DefineConstants>$(DefineConstants);OS_MUTEX</DefineConstants>
   </PropertyGroup>
 
-  <PropertyGroup Condition=" '$(TargetFramework)' == 'netstandard2.0' or '$(TargetFramework)' == 'netcoreapp3.0' ">
-    <DefineConstants>$(DefineConstants);OS_MUTEX</DefineConstants>
-  </PropertyGroup>
-
-  <ItemGroup Condition=" '$(TargetFramework)' == 'netstandard1.3' ">
-    <PackageReference Include="System.IO" Version="4.3.0" />
-    <PackageReference Include="System.IO.FileSystem" Version="4.3.0" />
-    <PackageReference Include="System.IO.FileSystem.Primitives" Version="4.3.0" />
-    <PackageReference Include="System.Text.Encoding.Extensions" Version="4.3.0" />
-    <PackageReference Include="System.Threading.Timer" Version="4.3.0" />
-    <PackageReference Include="System.Threading" Version="4.3.0" />
-    <PackageReference Include="System.Runtime.InteropServices" Version="4.3.0" />
-  </ItemGroup>
-
   <ItemGroup>
     <None Include="..\..\assets\serilog-sink-nuget.png" Pack="true" Visible="false" PackagePath="images\icon.png" />
   </ItemGroup>
-
+  
 </Project>

src/Serilog.Sinks.File/Sinks/File/FileSink.cs

@@ -31,7 +31,7 @@ public sealed class FileSink : IFileSink, IDisposable
         readonly long? _fileSizeLimitBytes;
         readonly bool _buffered;
         readonly object _syncRoot = new object();
-        readonly WriteCountingStream _countingStreamWrapper;
+        readonly WriteCountingStream? _countingStreamWrapper;
 
         /// <summary>Construct a <see cref="FileSink"/>.</summary>
         /// <param name="path">Path to the file.</param>
@@ -54,7 +54,7 @@ public sealed class FileSink : IFileSink, IDisposable
         /// <exception cref="UnauthorizedAccessException">The caller does not have the required permission to access the <paramref name="path"/></exception>
         /// <exception cref="ArgumentException">Invalid <paramref name="path"/></exception>
         [Obsolete("This type and constructor will be removed from the public API in a future version; use `WriteTo.File()` instead.")]
-        public FileSink(string path, ITextFormatter textFormatter, long? fileSizeLimitBytes, Encoding encoding = null, bool buffered = false)
+        public FileSink(string path, ITextFormatter textFormatter, long? fileSizeLimitBytes, Encoding? encoding = null, bool buffered = false)
             : this(path, textFormatter, fileSizeLimitBytes, encoding, buffered, null)
         {
         }
@@ -64,9 +64,9 @@ internal FileSink(
             string path,
             ITextFormatter textFormatter,
             long? fileSizeLimitBytes,
-            Encoding encoding,
+            Encoding? encoding,
             bool buffered,
-            FileLifecycleHooks hooks)
+            FileLifecycleHooks? hooks)
         {
             if (path == null) throw new ArgumentNullException(nameof(path));
             if (fileSizeLimitBytes.HasValue && fileSizeLimitBytes < 1) throw new ArgumentException("Invalid value provided; file size limit must be at least 1 byte, or null.");
@@ -105,7 +105,7 @@ bool IFileSink.EmitOrOverflow(LogEvent logEvent)
             {
                 if (_fileSizeLimitBytes != null)
                 {
-                    if (_countingStreamWrapper.CountedLength >= _fileSizeLimitBytes.Value)
+                    if (_countingStreamWrapper!.CountedLength >= _fileSizeLimitBytes.Value)
                         return false;
                 }
 

src/Serilog.Sinks.File/Sinks/File/RollingFileSink.cs

@@ -30,28 +30,28 @@ sealed class RollingFileSink : ILogEventSink, IFlushableFileSink, IDisposable
         readonly long? _fileSizeLimitBytes;
         readonly int? _retainedFileCountLimit;
         readonly TimeSpan? _retainedFileTimeLimit;
-        readonly Encoding _encoding;
+        readonly Encoding? _encoding;
         readonly bool _buffered;
         readonly bool _shared;
         readonly bool _rollOnFileSizeLimit;
-        readonly FileLifecycleHooks _hooks;
+        readonly FileLifecycleHooks? _hooks;
 
         readonly object _syncRoot = new object();
         bool _isDisposed;
         DateTime? _nextCheckpoint;
-        IFileSink _currentFile;
+        IFileSink? _currentFile;
         int? _currentFileSequence;
 
         public RollingFileSink(string path,
                               ITextFormatter textFormatter,
                               long? fileSizeLimitBytes,
                               int? retainedFileCountLimit,
-                              Encoding encoding,
+                              Encoding? encoding,
                               bool buffered,
                               bool shared,
                               RollingInterval rollingInterval,
                               bool rollOnFileSizeLimit,
-                              FileLifecycleHooks hooks,
+                              FileLifecycleHooks? hooks,
                               TimeSpan? retainedFileTimeLimit)
         {
             if (path == null) throw new ArgumentNullException(nameof(path));
@@ -125,7 +125,7 @@ void OpenFile(DateTime now, int? minSequence = null)
                 if (Directory.Exists(_roller.LogFileDirectory))
                 {
                     existingFiles = Directory.GetFiles(_roller.LogFileDirectory, _roller.DirectorySearchPattern)
-                                         .Select(Path.GetFileName);
+                                        .Select(f => Path.GetFileName(f));
                 }
             }
             catch (DirectoryNotFoundException) { }
@@ -184,7 +184,7 @@ void ApplyRetentionPolicy(string currentFilePath, DateTime now)
             // We consider the current file to exist, even if nothing's been written yet,
             // because files are only opened on response to an event being processed.
             var potentialMatches = Directory.GetFiles(_roller.LogFileDirectory, _roller.DirectorySearchPattern)
-                .Select(Path.GetFileName)
+                .Select(f => Path.GetFileName(f))
                 .Union(new[] { currentFileName });
 
             var newestFirst = _roller

src/Serilog.Sinks.File/Sinks/File/SharedFileSink.AtomicAppend.cs

@@ -58,7 +58,7 @@ public sealed class SharedFileSink : IFileSink, IDisposable
         /// <exception cref="PathTooLongException">When <paramref name="path"/> is too long</exception>
         /// <exception cref="UnauthorizedAccessException">The caller does not have the required permission to access the <paramref name="path"/></exception>
         /// <exception cref="ArgumentException">Invalid <paramref name="path"/></exception>
-        public SharedFileSink(string path, ITextFormatter textFormatter, long? fileSizeLimitBytes, Encoding encoding = null)
+        public SharedFileSink(string path, ITextFormatter textFormatter, long? fileSizeLimitBytes, Encoding? encoding = null)
         {
             if (fileSizeLimitBytes.HasValue && fileSizeLimitBytes < 1)
                 throw new ArgumentException("Invalid value provided; file size limit must be at least 1 byte, or null");

src/Serilog.Sinks.File/Sinks/File/SharedFileSink.OSMutex.cs

@@ -57,7 +57,7 @@ public sealed class SharedFileSink : IFileSink, IDisposable
         /// <exception cref="PathTooLongException">When <paramref name="path"/> is too long</exception>
         /// <exception cref="UnauthorizedAccessException">The caller does not have the required permission to access the <paramref name="path"/></exception>
         /// <exception cref="ArgumentException">Invalid <paramref name="path"/></exception>
-        public SharedFileSink(string path, ITextFormatter textFormatter, long? fileSizeLimitBytes, Encoding encoding = null)
+        public SharedFileSink(string path, ITextFormatter textFormatter, long? fileSizeLimitBytes, Encoding? encoding = null)
         {
             if (path == null) throw new ArgumentNullException(nameof(path));
             if (fileSizeLimitBytes.HasValue && fileSizeLimitBytes < 1)