More nullable fixes and code cleanup, use TaskCanceledException instead of OperationCanceledException

Author: paulirwin

Directory.Build.targets

@@ -51,6 +51,7 @@
     Condition=" $(TargetFramework.StartsWith('net8.')) Or $(TargetFramework.StartsWith('net9.')) ">
 
     <DefineConstants>$(DefineConstants);FEATURE_ASPNETCORE_TESTHOST</DefineConstants>
+    <DefineConstants>$(DefineConstants);FEATURE_CANCELLATIONTOKENSOURCE_CANCELASYNC</DefineConstants>
 
   </PropertyGroup>
 

src/Lucene.Net.Replicator/IAsyncReplicator.cs

@@ -18,7 +18,7 @@ public interface IAsyncReplicator
         /// <param name="currentVersion">Current version of the index.</param>
         /// <param name="cancellationToken">Cancellation token.</param>
         /// <returns>A <see cref="SessionToken"/> if an update exists; otherwise, <c>null</c>.</returns>
-        Task<SessionToken?> CheckForUpdateAsync(string currentVersion, CancellationToken cancellationToken = default);
+        Task<SessionToken?> CheckForUpdateAsync(string? currentVersion, CancellationToken cancellationToken = default);
 
         /// <summary>
         /// Returns a stream for the requested file and source.

src/Lucene.Net.Replicator/IndexAndTaxonomyReplicationHandler.cs

@@ -6,6 +6,8 @@
 using System.IO;
 using Directory = Lucene.Net.Store.Directory;
 
+#nullable enable
+
 namespace Lucene.Net.Replicator
 {
     /*
@@ -50,17 +52,17 @@ public class IndexAndTaxonomyReplicationHandler : IReplicationHandler
 
         private readonly Directory indexDirectory;
         private readonly Directory taxonomyDirectory;
-        private readonly Action callback;
+        private readonly Action? callback;
 
-        private volatile IDictionary<string, IList<RevisionFile>> currentRevisionFiles;
-        private volatile string currentVersion;
+        private volatile IDictionary<string, IList<RevisionFile>>? currentRevisionFiles;
+        private volatile string? currentVersion;
         private volatile InfoStream infoStream = InfoStream.Default;
 
         /// <summary>
         /// Constructor with the given index directory and callback to notify when the indexes were updated.
         /// </summary>
         /// <exception cref="IOException"></exception>
-        public IndexAndTaxonomyReplicationHandler(Directory indexDirectory, Directory taxonomyDirectory, Action callback)
+        public IndexAndTaxonomyReplicationHandler(Directory indexDirectory, Directory taxonomyDirectory, Action? callback)
         {
             this.indexDirectory = indexDirectory;
             this.taxonomyDirectory = taxonomyDirectory;
@@ -73,24 +75,24 @@ public IndexAndTaxonomyReplicationHandler(Directory indexDirectory, Directory ta
             bool taxonomyExists = DirectoryReader.IndexExists(taxonomyDirectory);
 
             if (indexExists != taxonomyExists)
-                throw IllegalStateException.Create(string.Format("search and taxonomy indexes must either both exist or not: index={0} taxo={1}", indexExists, taxonomyExists));
+                throw IllegalStateException.Create($"search and taxonomy indexes must either both exist or not: index={indexExists} taxo={taxonomyExists}");
 
             if (indexExists)
             {
-                IndexCommit indexCommit = IndexReplicationHandler.GetLastCommit(indexDirectory);
-                IndexCommit taxonomyCommit = IndexReplicationHandler.GetLastCommit(taxonomyDirectory);
+                IndexCommit? indexCommit = IndexReplicationHandler.GetLastCommit(indexDirectory);
+                IndexCommit? taxonomyCommit = IndexReplicationHandler.GetLastCommit(taxonomyDirectory);
 
                 currentRevisionFiles = IndexAndTaxonomyRevision.RevisionFiles(indexCommit, taxonomyCommit);
                 currentVersion = IndexAndTaxonomyRevision.RevisionVersion(indexCommit, taxonomyCommit);
 
                 WriteToInfoStream(
-                    string.Format("constructor(): currentVersion={0} currentRevisionFiles={1}", currentVersion, currentRevisionFiles),
-                    string.Format("constructor(): indexCommit={0} taxoCommit={1}", indexCommit, taxonomyCommit));
+                    $"constructor(): currentVersion={currentVersion} currentRevisionFiles={currentRevisionFiles}",
+                    $"constructor(): indexCommit={indexCommit} taxoCommit={taxonomyCommit}");
             }
         }
 
-        public virtual string CurrentVersion => currentVersion;
-        public virtual IDictionary<string, IList<RevisionFile>> CurrentRevisionFiles => currentRevisionFiles;
+        public virtual string? CurrentVersion => currentVersion;
+        public virtual IDictionary<string, IList<RevisionFile>>? CurrentRevisionFiles => currentRevisionFiles;
 
         public virtual void RevisionReady(string version,
             IDictionary<string, IList<RevisionFile>> revisionFiles,
@@ -101,8 +103,8 @@ public virtual void RevisionReady(string version,
             Directory indexClientDirectory = sourceDirectory[IndexAndTaxonomyRevision.INDEX_SOURCE];
             IList<string> taxonomyFiles = copiedFiles[IndexAndTaxonomyRevision.TAXONOMY_SOURCE];
             IList<string> indexFiles = copiedFiles[IndexAndTaxonomyRevision.INDEX_SOURCE];
-            string taxonomySegmentsFile = IndexReplicationHandler.GetSegmentsFile(taxonomyFiles, true);
-            string indexSegmentsFile = IndexReplicationHandler.GetSegmentsFile(indexFiles, false);
+            string? taxonomySegmentsFile = IndexReplicationHandler.GetSegmentsFile(taxonomyFiles, true);
+            string indexSegmentsFile = IndexReplicationHandler.GetSegmentsFile(indexFiles, false)!; // [!]: verified by GetSegmentsFile
 
             bool success = false;
             try
@@ -132,7 +134,11 @@ public virtual void RevisionReady(string version,
             {
                 if (!success)
                 {
-                    taxonomyFiles.Add(taxonomySegmentsFile); // add it back so it gets deleted too
+                    if (taxonomySegmentsFile != null) // LUCENENET specific - null check
+                    {
+                        taxonomyFiles.Add(taxonomySegmentsFile); // add it back so it gets deleted too
+                    }
+
                     IndexReplicationHandler.CleanupFilesOnFailure(taxonomyDirectory, taxonomyFiles);
                     indexFiles.Add(indexSegmentsFile); // add it back so it gets deleted too
                     IndexReplicationHandler.CleanupFilesOnFailure(indexDirectory, indexFiles);
@@ -188,6 +194,7 @@ private void WriteToInfoStream(params string[] messages)
         public virtual InfoStream InfoStream
         {
             get => infoStream;
+            // ReSharper disable once NullCoalescingConditionIsAlwaysNotNullAccordingToAPIContract
             set => infoStream = value ?? InfoStream.NO_OUTPUT;
         }
     }

src/Lucene.Net.Replicator/IndexReplicationHandler.cs

@@ -9,6 +9,8 @@
 using JCG = J2N.Collections.Generic;
 using Directory = Lucene.Net.Store.Directory;
 
+#nullable enable
+
 namespace Lucene.Net.Replicator
 {
     /*
@@ -57,10 +59,10 @@ public class IndexReplicationHandler : IReplicationHandler
         public const string INFO_STREAM_COMPONENT = "IndexReplicationHandler";
 
         private readonly Directory indexDirectory;
-        private readonly Action callback;
+        private readonly Action? callback;
 
-        private volatile IDictionary<string, IList<RevisionFile>> currentRevisionFiles;
-        private volatile string currentVersion;
+        private volatile IDictionary<string, IList<RevisionFile>>? currentRevisionFiles;
+        private volatile string? currentVersion;
         private volatile InfoStream infoStream;
 
         //Note: LUCENENET Specific Utility Method
@@ -78,7 +80,7 @@ private void WriteToInfoStream(params string[] messages)
         /// <c>null</c> if there are no commits.
         /// </summary>
         /// <exception cref="IOException"></exception>
-        public static IndexCommit GetLastCommit(Directory directory)
+        public static IndexCommit? GetLastCommit(Directory directory)
         {
             try
             {
@@ -106,7 +108,7 @@ public static IndexCommit GetLastCommit(Directory directory)
         /// The reason why the code fails instead of putting segments_N file last is
         /// that this indicates an error in the <see cref="IRevision"/> implementation.
         /// </summary>
-        public static string GetSegmentsFile(IList<string> files, bool allowEmpty)
+        public static string? GetSegmentsFile(IList<string> files, bool allowEmpty)
         {
             if (files.Count == 0)
             {
@@ -121,7 +123,7 @@ public static string GetSegmentsFile(IList<string> files, bool allowEmpty)
             if (!segmentsFile.StartsWith(IndexFileNames.SEGMENTS, StringComparison.Ordinal) || segmentsFile.Equals(IndexFileNames.SEGMENTS_GEN, StringComparison.Ordinal))
             {
                 throw IllegalStateException.Create(
-                    string.Format("last file to copy+sync must be segments_N but got {0}; check your Revision implementation!", segmentsFile));
+                    $"last file to copy+sync must be segments_N but got {segmentsFile}; check your Revision implementation!");
             }
             return segmentsFile;
         }
@@ -157,11 +159,11 @@ public static void CleanupFilesOnFailure(Directory directory, IList<string> file
         /// directory. It suppresses any exceptions that occur, as this can be retried
         /// the next time.
         /// </remarks>
-        public static void CleanupOldIndexFiles(Directory directory, string segmentsFile)
+        public static void CleanupOldIndexFiles(Directory directory, string? segmentsFile)
         {
             try
             {
-                IndexCommit commit = GetLastCommit(directory);
+                IndexCommit? commit = GetLastCommit(directory);
                 // commit is null means weird IO errors occurred, ignore them
                 // if there were any IO errors reading the expected commit point (i.e.
                 // segments files mismatch), then ignore that commit either.
@@ -218,7 +220,7 @@ public static void CopyFiles(Directory source, Directory target, IList<string> f
         /// the generation from the given <paramref name="segmentsFile"/>. If it is <c>null</c>,
         /// this method deletes segments.gen from the directory.
         /// </summary>
-        public static void WriteSegmentsGen(string segmentsFile, Directory directory)
+        public static void WriteSegmentsGen(string? segmentsFile, Directory directory)
         {
             if (segmentsFile != null)
             {
@@ -240,9 +242,9 @@ public static void WriteSegmentsGen(string segmentsFile, Directory directory)
         /// Constructor with the given index directory and callback to notify when the
         /// indexes were updated.
         /// </summary>
-        public IndexReplicationHandler(Directory indexDirectory, Action callback)
+        public IndexReplicationHandler(Directory indexDirectory, Action? callback)
         {
-            this.InfoStream = InfoStream.Default;
+            infoStream = InfoStream.Default;
             this.callback = callback;
             this.indexDirectory = indexDirectory;
 
@@ -258,25 +260,26 @@ public IndexReplicationHandler(Directory indexDirectory, Action callback)
                 currentRevisionFiles = IndexRevision.RevisionFiles(commit);
 
                 WriteToInfoStream(
-                    string.Format("constructor(): currentVersion={0} currentRevisionFiles={1}", currentVersion, currentRevisionFiles),
-                    string.Format("constructor(): commit={0}", commit));
+                    $"constructor(): currentVersion={currentVersion} currentRevisionFiles={currentRevisionFiles}",
+                    $"constructor(): commit={commit}");
             }
         }
 
-        public virtual string CurrentVersion => currentVersion;
+        public virtual string? CurrentVersion => currentVersion;
 
-        public virtual IDictionary<string, IList<RevisionFile>> CurrentRevisionFiles => currentRevisionFiles;
+        public virtual IDictionary<string, IList<RevisionFile>>? CurrentRevisionFiles => currentRevisionFiles;
 
         public virtual void RevisionReady(string version,
             IDictionary<string, IList<RevisionFile>> revisionFiles,
             IDictionary<string, IList<string>> copiedFiles,
             IDictionary<string, Directory> sourceDirectory)
         {
-            if (revisionFiles.Count > 1) throw new ArgumentException(string.Format("this handler handles only a single source; got {0}", revisionFiles.Keys));
+            if (revisionFiles.Count > 1)
+                throw new ArgumentException($"this handler handles only a single source; got {revisionFiles.Keys}");
 
             Directory clientDirectory = sourceDirectory.Values.First();
             IList<string> files = copiedFiles.Values.First();
-            string segmentsFile = GetSegmentsFile(files, false);
+            string segmentsFile = GetSegmentsFile(files, false)!; // [!]: verified by GetSegmentsFile
 
             bool success = false;
             try
@@ -306,7 +309,7 @@ public virtual void RevisionReady(string version,
             currentRevisionFiles = revisionFiles;
             currentVersion = version;
 
-            WriteToInfoStream(string.Format("revisionReady(): currentVersion={0} currentRevisionFiles={1}", currentVersion, currentRevisionFiles));
+            WriteToInfoStream($"revisionReady(): currentVersion={currentVersion} currentRevisionFiles={currentRevisionFiles}");
 
             // update the segments.gen file
             WriteSegmentsGen(segmentsFile, indexDirectory);
@@ -339,6 +342,7 @@ public virtual void RevisionReady(string version,
         public virtual InfoStream InfoStream
         {
             get => infoStream;
+            // ReSharper disable once NullCoalescingConditionIsAlwaysNotNullAccordingToAPIContract
             set => infoStream = value ?? InfoStream.NO_OUTPUT;
         }
     }