apacheGH-41602: [C#] Resolve build warnings (apache#41645)

### What changes are included in this PR?

Adds annotations or suppressions to disable build warnings. Configures projects to produce an error on warnings.

### Are these changes tested?

Changes are covered by existing tests.

Closes apache#41602

* GitHub Issue: apache#41602

Authored-by: Curt Hagenlocher <[email protected]>
Signed-off-by: Curt Hagenlocher <[email protected]>

csharp/Directory.Build.props

@@ -37,12 +37,13 @@
     <LangVersion>latest</LangVersion>
     <SignAssembly>true</SignAssembly>
     <AssemblyOriginatorKeyFile>$(CSharpDir)ApacheArrow.snk</AssemblyOriginatorKeyFile>
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
   </PropertyGroup>
 
   <!-- NuGet properties -->
   <PropertyGroup>
     <Authors>The Apache Software Foundation</Authors>
-    <PackageIconUrl>https://www.apache.org/images/feather.png</PackageIconUrl>
+    <PackageIcon>feather.png</PackageIcon>
     <!-- We can't use PackageLicenseExpression; the license file also contains 3rd-party notices. -->
     <PackageLicenseFile>LICENSE.txt</PackageLicenseFile>
     <PackageProjectUrl>https://arrow.apache.org/</PackageProjectUrl>
@@ -55,6 +56,7 @@
 
   <ItemGroup Condition="'$(IsPackable)' == 'true'">
     <Content Include="$(RepoRoot)LICENSE.txt" Pack="true" PackagePath="" />
+    <Content Include="$(CSharpDir)/feather.png" Link="feather.png" Pack="true" PackagePath="\" />
   </ItemGroup>
 
 </Project>

csharp/src/Apache.Arrow/Arrays/BinaryArray.cs

@@ -383,8 +383,8 @@ IEnumerator<byte[]> IEnumerable<byte[]>.GetEnumerator()
 
         int ICollection<byte[]>.Count => Length;
         bool ICollection<byte[]>.IsReadOnly => true;
-        void ICollection<byte[]>.Add(byte[]? item) => throw new NotSupportedException("Collection is read-only.");
-        bool ICollection<byte[]>.Remove(byte[]? item) => throw new NotSupportedException("Collection is read-only.");
+        void ICollection<byte[]>.Add(byte[] item) => throw new NotSupportedException("Collection is read-only.");
+        bool ICollection<byte[]>.Remove(byte[] item) => throw new NotSupportedException("Collection is read-only.");
         void ICollection<byte[]>.Clear() => throw new NotSupportedException("Collection is read-only.");
 
         bool ICollection<byte[]>.Contains(byte[] item)

csharp/src/Apache.Arrow/Arrays/Decimal256Array.cs

@@ -13,6 +13,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#nullable enable
+
 using System;
 using System.Collections;
 using System.Collections.Generic;
@@ -23,7 +25,7 @@
 
 namespace Apache.Arrow
 {
-    public class Decimal256Array : FixedSizeBinaryArray, IReadOnlyList<SqlDecimal?>, IReadOnlyList<string>
+    public class Decimal256Array : FixedSizeBinaryArray, IReadOnlyList<SqlDecimal?>, IReadOnlyList<string?>
     {
         public class Builder : BuilderBase<Decimal256Array, Builder>
         {
@@ -178,7 +180,7 @@ public Decimal256Array(ArrayData data)
             return list;
         }
 
-        public string GetString(int index)
+        public string? GetString(int index)
         {
             if (IsNull(index))
             {
@@ -230,17 +232,17 @@ public bool TryGetSqlDecimal(int index, out SqlDecimal? value)
             }
         }
 
-        int IReadOnlyCollection<string>.Count => Length;
-        string? IReadOnlyList<string>.this[int index] => GetString(index);
+        int IReadOnlyCollection<string?>.Count => Length;
+        string? IReadOnlyList<string?>.this[int index] => GetString(index);
 
-        IEnumerator<string> IEnumerable<string>.GetEnumerator()
+        IEnumerator<string?> IEnumerable<string?>.GetEnumerator()
         {
             for (int index = 0; index < Length; index++)
             {
                 yield return GetString(index);
             }
         }
 
-        IEnumerator IEnumerable.GetEnumerator() => ((IEnumerable<string>)this).GetEnumerator();
+        IEnumerator IEnumerable.GetEnumerator() => ((IEnumerable<string?>)this).GetEnumerator();
     }
 }

csharp/src/Apache.Arrow/Memory/NativeMemoryManager.cs

@@ -40,10 +40,12 @@ internal NativeMemoryManager(INativeAllocationOwner owner, IntPtr ptr, int offse
             _owner = owner;
         }
 
+#pragma warning disable CA2015 // TODO: is this correct?
         ~NativeMemoryManager()
         {
             Dispose(false);
         }
+#pragma warning restore CA2015
 
         public override unsafe Span<byte> GetSpan()
         {

csharp/test/Apache.Arrow.Flight.Sql.Tests/FlightSqlServerTests.cs

@@ -14,6 +14,7 @@
 // limitations under the License.
 
 #nullable enable
+
 using System;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
@@ -65,7 +66,7 @@ public async Task EnsureTheCorrectActionsAreGiven()
         var streamWriter = new MockServerStreamWriter<FlightActionType>();
 
         //When
-        await producer.ListActions(streamWriter, new MockServerCallContext()).ConfigureAwait(false);
+        await producer.ListActions(streamWriter, new MockServerCallContext());
         var actions = streamWriter.Messages.ToArray();
 
         Assert.Equal(FlightSqlUtils.FlightSqlActions, actions);
@@ -115,7 +116,7 @@ public void EnsureTableSchemaIsCorrectWithoutTableSchema(bool includeTableSchema
     [InlineData(typeof(CommandGetImportedKeys), "GetImportedKeysFlightInfo")]
     [InlineData(typeof(CommandGetCrossReference), "GetCrossReferenceFlightInfo")]
     [InlineData(typeof(CommandGetXdbcTypeInfo), "GetXdbcTypeFlightInfo")]
-    public async void EnsureGetFlightInfoIsCorrectlyRoutedForCommand(Type commandType, string expectedResult)
+    public async Task EnsureGetFlightInfoIsCorrectlyRoutedForCommand(Type commandType, string expectedResult)
     {
         //Given
         var command = (IMessage) Activator.CreateInstance(commandType)!;
@@ -131,7 +132,7 @@ public async void EnsureGetFlightInfoIsCorrectlyRoutedForCommand(Type commandTyp
 
 
     [Fact]
-    public async void EnsureAnInvalidOperationExceptionIsThrownWhenACommandIsNotSupportedAndHasNoDescriptor()
+    public async Task EnsureAnInvalidOperationExceptionIsThrownWhenACommandIsNotSupportedAndHasNoDescriptor()
     {
         //Given
         var producer = new TestFlightSqlSever();
@@ -145,7 +146,7 @@ public async void EnsureAnInvalidOperationExceptionIsThrownWhenACommandIsNotSupp
     }
 
     [Fact]
-    public async void EnsureAnInvalidOperationExceptionIsThrownWhenACommandIsNotSupported()
+    public async Task EnsureAnInvalidOperationExceptionIsThrownWhenACommandIsNotSupported()
     {
         //Given
         var producer = new TestFlightSqlSever();
@@ -175,7 +176,7 @@ public async void EnsureAnInvalidOperationExceptionIsThrownWhenACommandIsNotSupp
     [InlineData(typeof(CommandGetImportedKeys), "DoGetImportedKeys")]
     [InlineData(typeof(CommandGetCrossReference), "DoGetCrossReference")]
     [InlineData(typeof(CommandGetXdbcTypeInfo), "DoGetXbdcTypeInfo")]
-    public async void EnsureDoGetIsCorrectlyRoutedForADoGetCommand(Type commandType, string expectedResult)
+    public async Task EnsureDoGetIsCorrectlyRoutedForADoGetCommand(Type commandType, string expectedResult)
     {
         //Given
         var producer = new TestFlightSqlSever();
@@ -192,7 +193,7 @@ public async void EnsureDoGetIsCorrectlyRoutedForADoGetCommand(Type commandType,
     }
 
     [Fact]
-    public async void EnsureAnInvalidOperationExceptionIsThrownWhenADoGetCommandIsNotSupported()
+    public async Task EnsureAnInvalidOperationExceptionIsThrownWhenADoGetCommandIsNotSupported()
     {
         //Given
         var producer = new TestFlightSqlSever();
@@ -213,7 +214,7 @@ public async void EnsureAnInvalidOperationExceptionIsThrownWhenADoGetCommandIsNo
     [InlineData(SqlAction.CloseRequest, typeof(ActionClosePreparedStatementRequest), "ClosePreparedStatement")]
     [InlineData(SqlAction.CreateRequest, typeof(ActionCreatePreparedStatementRequest), "CreatePreparedStatement")]
     [InlineData("BadCommand", typeof(ActionCreatePreparedStatementRequest), "Action type BadCommand not supported", true)]
-    public async void EnsureDoActionIsCorrectlyRoutedForAnActionRequest(string actionType, Type actionBodyType, string expectedResponse, bool isException = false)
+    public async Task EnsureDoActionIsCorrectlyRoutedForAnActionRequest(string actionType, Type actionBodyType, string expectedResponse, bool isException = false)
     {
         //Given
         var producer = new TestFlightSqlSever();
@@ -237,19 +238,19 @@ public async void EnsureDoActionIsCorrectlyRoutedForAnActionRequest(string actio
     [InlineData(typeof(CommandPreparedStatementQuery), "PutPreparedStatementQuery")]
     [InlineData(typeof(CommandPreparedStatementUpdate), "PutPreparedStatementUpdate")]
     [InlineData(typeof(CommandGetXdbcTypeInfo), "Command CommandGetXdbcTypeInfo not supported", true)]
-    public async void EnsureDoPutIsCorrectlyRoutedForTheCommand(Type commandType, string expectedResponse, bool isException = false)
+    public async Task EnsureDoPutIsCorrectlyRoutedForTheCommand(Type commandType, string expectedResponse, bool isException = false)
     {
         //Given
         var command = (IMessage) Activator.CreateInstance(commandType)!;
         var producer = new TestFlightSqlSever();
         var descriptor = FlightDescriptor.CreateCommandDescriptor(command.PackAndSerialize().ToArray());
         var recordBatch = new RecordBatch(new Schema(new List<Field>(), null), System.Array.Empty<Int8Array>(), 0);
-        var reader = new MockStreamReader<FlightData>(await recordBatch.ToFlightData(descriptor).ConfigureAwait(false));
+        var reader = new MockStreamReader<FlightData>(await recordBatch.ToFlightData(descriptor));
         var batchReader = new FlightServerRecordBatchStreamReader(reader);
         var mockStreamWriter = new MockServerStreamWriter<FlightPutResult>();
 
         //When
-        async Task Act() => await producer.DoPut(batchReader, mockStreamWriter, new MockServerCallContext()).ConfigureAwait(false);
+        async Task Act() => await producer.DoPut(batchReader, mockStreamWriter, new MockServerCallContext());
         var exception = await Record.ExceptionAsync(Act);
         string? actualMessage = isException ? exception?.Message : mockStreamWriter.Messages[0].ApplicationMetadata.ToStringUtf8();
 
@@ -271,7 +272,7 @@ private class MockServerCallContext : ServerCallContext
         protected override CancellationToken CancellationTokenCore => default;
         protected override Metadata ResponseTrailersCore => new();
         protected override Status StatusCore { get; set; }
-        protected override WriteOptions WriteOptionsCore { get; set; } = WriteOptions.Default;
+        protected override WriteOptions? WriteOptionsCore { get; set; } = WriteOptions.Default;
         protected override AuthContext AuthContextCore => new("", new Dictionary<string, List<AuthProperty>>());
     }
 }
@@ -325,7 +326,7 @@ public static async Task<Schema> GetSchema(this IEnumerable<FlightData> flightDa
     public static async Task<IEnumerable<FlightData>> ToFlightData(this RecordBatch recordBatch, FlightDescriptor? descriptor = null)
     {
         var responseStream = new MockFlightServerRecordBatchStreamWriter();
-        await responseStream.WriteRecordBatchAsync(recordBatch).ConfigureAwait(false);
+        await responseStream.WriteRecordBatchAsync(recordBatch);
         if (descriptor == null)
         {
             return responseStream.FlightData;

csharp/test/Apache.Arrow.Flight.Tests/FlightTests.cs

@@ -288,9 +288,9 @@ public async Task TestHandshake()
         {
             var duplexStreamingCall = _flightClient.Handshake();
 
-            await duplexStreamingCall.RequestStream.WriteAsync(new FlightHandshakeRequest(ByteString.Empty)).ConfigureAwait(false);
-            await duplexStreamingCall.RequestStream.CompleteAsync().ConfigureAwait(false);
-            var results = await duplexStreamingCall.ResponseStream.ToListAsync().ConfigureAwait(false);
+            await duplexStreamingCall.RequestStream.WriteAsync(new FlightHandshakeRequest(ByteString.Empty));
+            await duplexStreamingCall.RequestStream.CompleteAsync();
+            var results = await duplexStreamingCall.ResponseStream.ToListAsync();
 
             Assert.Single(results);
             Assert.Equal("Done", results.First().Payload.ToStringUtf8());
@@ -303,10 +303,10 @@ public async Task TestSingleExchange()
             var duplexStreamingCall = _flightClient.DoExchange(flightDescriptor);
             var expectedBatch = CreateTestBatch(0, 100);
 
-            await duplexStreamingCall.RequestStream.WriteAsync(expectedBatch).ConfigureAwait(false);
-            await duplexStreamingCall.RequestStream.CompleteAsync().ConfigureAwait(false);
+            await duplexStreamingCall.RequestStream.WriteAsync(expectedBatch);
+            await duplexStreamingCall.RequestStream.CompleteAsync();
 
-            var results = await duplexStreamingCall.ResponseStream.ToListAsync().ConfigureAwait(false);
+            var results = await duplexStreamingCall.ResponseStream.ToListAsync();
 
             Assert.Single(results);
             ArrowReaderVerifier.CompareBatches(expectedBatch, results.FirstOrDefault());
@@ -320,11 +320,11 @@ public async Task TestMultipleExchange()
             var expectedBatch1 = CreateTestBatch(0, 100);
             var expectedBatch2 = CreateTestBatch(100, 100);
 
-            await duplexStreamingCall.RequestStream.WriteAsync(expectedBatch1).ConfigureAwait(false);
-            await duplexStreamingCall.RequestStream.WriteAsync(expectedBatch2).ConfigureAwait(false);
-            await duplexStreamingCall.RequestStream.CompleteAsync().ConfigureAwait(false);
+            await duplexStreamingCall.RequestStream.WriteAsync(expectedBatch1);
+            await duplexStreamingCall.RequestStream.WriteAsync(expectedBatch2);
+            await duplexStreamingCall.RequestStream.CompleteAsync();
 
-            var results = await duplexStreamingCall.ResponseStream.ToListAsync().ConfigureAwait(false);
+            var results = await duplexStreamingCall.ResponseStream.ToListAsync();
 
             ArrowReaderVerifier.CompareBatches(expectedBatch1, results[0]);
             ArrowReaderVerifier.CompareBatches(expectedBatch2, results[1]);
@@ -338,8 +338,8 @@ public async Task TestExchangeWithMetadata()
             var expectedBatch = CreateTestBatch(0, 100);
             var expectedMetadata = ByteString.CopyFromUtf8("test metadata");
 
-            await duplexStreamingCall.RequestStream.WriteAsync(expectedBatch, expectedMetadata).ConfigureAwait(false);
-            await duplexStreamingCall.RequestStream.CompleteAsync().ConfigureAwait(false);
+            await duplexStreamingCall.RequestStream.WriteAsync(expectedBatch, expectedMetadata);
+            await duplexStreamingCall.RequestStream.CompleteAsync();
 
             List<ByteString> actualMetadata = new List<ByteString>();
             List<RecordBatch> actualBatch = new List<RecordBatch>();
@@ -358,9 +358,9 @@ public async Task TestHandshakeWithSpecificMessage()
         {
             var duplexStreamingCall = _flightClient.Handshake();
 
-            await duplexStreamingCall.RequestStream.WriteAsync(new FlightHandshakeRequest(ByteString.CopyFromUtf8("Hello"))).ConfigureAwait(false);
-            await duplexStreamingCall.RequestStream.CompleteAsync().ConfigureAwait(false);
-            var results = await duplexStreamingCall.ResponseStream.ToListAsync().ConfigureAwait(false);
+            await duplexStreamingCall.RequestStream.WriteAsync(new FlightHandshakeRequest(ByteString.CopyFromUtf8("Hello")));
+            await duplexStreamingCall.RequestStream.CompleteAsync();
+            var results = await duplexStreamingCall.ResponseStream.ToListAsync();
 
             Assert.Single(results);
             Assert.Equal("Hello handshake", results.First().Payload.ToStringUtf8());

csharp/test/Apache.Arrow.Tests/ArrowArrayTests.cs

@@ -212,11 +212,11 @@ private static void TestPrimitiveArrayAsCollection<T, TArray, TArrayBuilder>(IRe
         // Parameter 'values' must contain four values. The last value must be distinct from the rest.
         private static void TestObjectArrayAsCollection<T, TArray>(TArray array, T nullValue, IReadOnlyList<T> values)
             where T : class
-            where TArray : IArrowArray, ICollection<T?>
+            where TArray : IArrowArray, ICollection<T>
         {
             Assert.NotNull(array);
             Assert.Equal(4, values.Count);
-            var collection = (ICollection<T?>)array;
+            var collection = (ICollection<T>)array;
 
             Assert.Equal(array.Length, collection.Count);
             Assert.Equal(4, collection.Count);
@@ -232,7 +232,7 @@ private static void TestObjectArrayAsCollection<T, TArray>(TArray array, T nullV
             Assert.False(collection.Contains(values[3]));
 
             T sentinel = values[2];
-            T?[] destArr = { sentinel, sentinel, sentinel, sentinel, sentinel, sentinel };
+            T[] destArr = { sentinel, sentinel, sentinel, sentinel, sentinel, sentinel };
             collection.CopyTo(destArr, 1);
             Assert.Equal(sentinel, destArr[0]);
             Assert.Equal(values[0], destArr[1]);

csharp/test/Apache.Arrow.Tests/DurationArrayTests.cs

@@ -115,7 +115,7 @@ public void AppendTimeSpanGivesSameTimeSpan(TimeSpan? timeSpan, DurationType typ
                 Assert.Equal(timeSpan, array.GetTimeSpan(0));
 
                 IReadOnlyList<TimeSpan?> asList = array;
-                Assert.Equal(1, asList.Count);
+                Assert.Single(asList);
                 Assert.Equal(timeSpan, asList[0]);
             }
         }