feat: use DateOnly

src/Parquet.Data.Analysis/Extensions.cs

@@ -79,6 +79,7 @@ private static async Task<DataFrameColumn> CreateColumnAsync(
         if(t == typeof(float)) return new SingleDataFrameColumn(name, await ReadAsync<float>(rgr, field, rowCount, ct));
         if(t == typeof(double)) return new DoubleDataFrameColumn(name, await ReadAsync<double>(rgr, field, rowCount, ct));
         if(t == typeof(decimal)) return new DecimalDataFrameColumn(name, await ReadAsync<decimal>(rgr, field, rowCount, ct));
+        if(t == typeof(DateOnly)) return new PrimitiveDataFrameColumn<DateOnly>(name, await ReadAsync<DateOnly>(rgr, field, rowCount, ct));
         if(t == typeof(DateTime)) return new DateTimeDataFrameColumn(name, await ReadAsync<DateTime>(rgr, field, rowCount, ct));
         if(t == typeof(TimeSpan)) return new PrimitiveDataFrameColumn<TimeSpan>(name, await ReadAsync<TimeSpan>(rgr, field, rowCount, ct));
         if(t == typeof(string)) return new StringDataFrameColumn(name, await ReadStringsAsync(rgr, field, rowCount, ct));
@@ -103,6 +104,7 @@ private static async Task AppendToColumnAsync(
         if(t == typeof(float)) { Append((PrimitiveDataFrameColumn<float>)col, await ReadAsync<float>(rgr, field, rowCount, ct)); return; }
         if(t == typeof(double)) { Append((PrimitiveDataFrameColumn<double>)col, await ReadAsync<double>(rgr, field, rowCount, ct)); return; }
         if(t == typeof(decimal)) { Append((PrimitiveDataFrameColumn<decimal>)col, await ReadAsync<decimal>(rgr, field, rowCount, ct)); return; }
+        if(t == typeof(DateOnly)) { Append((PrimitiveDataFrameColumn<DateOnly>)col, await ReadAsync<DateOnly>(rgr, field, rowCount, ct)); return; }
         if(t == typeof(DateTime)) { Append((PrimitiveDataFrameColumn<DateTime>)col, await ReadAsync<DateTime>(rgr, field, rowCount, ct)); return; }
         if(t == typeof(TimeSpan)) { Append((PrimitiveDataFrameColumn<TimeSpan>)col, await ReadAsync<TimeSpan>(rgr, field, rowCount, ct)); return; }
         if(t == typeof(string)) { Append((StringDataFrameColumn)col, await ReadStringsAsync(rgr, field, rowCount, ct)); return; }
@@ -153,6 +155,7 @@ private static async Task WriteColumnAsync(DataField field, DataFrameColumn col,
         if(t == typeof(float)) { await rgw.WriteAsync<float>(field, ((PrimitiveDataFrameColumn<float>)col).ToArray().AsMemory()); return; }
         if(t == typeof(double)) { await rgw.WriteAsync<double>(field, ((PrimitiveDataFrameColumn<double>)col).ToArray().AsMemory()); return; }
         if(t == typeof(decimal)) { await rgw.WriteAsync<decimal>(field, ((PrimitiveDataFrameColumn<decimal>)col).ToArray().AsMemory()); return; }
+        if(t == typeof(DateOnly)) { await rgw.WriteAsync<DateOnly>(field, ((PrimitiveDataFrameColumn<DateOnly>)col).ToArray().AsMemory()); return; }
         if(t == typeof(DateTime)) { await rgw.WriteAsync<DateTime>(field, ((PrimitiveDataFrameColumn<DateTime>)col).ToArray().AsMemory()); return; }
         if(t == typeof(TimeSpan)) { await rgw.WriteAsync<TimeSpan>(field, ((PrimitiveDataFrameColumn<TimeSpan>)col).ToArray().AsMemory()); return; }
         if(t == typeof(string)) {

src/Parquet.Test/ParquetReaderOnTestFilesTest.cs

@@ -37,16 +37,16 @@ public async Task Datetypes_all(string parquetFile) {
         await using ParquetReader r = await ParquetReader.CreateAsync(s);
         using ParquetRowGroupReader rgr = r.OpenRowGroupReader(0);
 
-        var col0 = new DateTime?[rgr.RowGroup.NumRows];
+        var col0 = new DateOnly?[rgr.RowGroup.NumRows];
         var col1 = new DateTime?[rgr.RowGroup.NumRows];
-        await rgr.ReadAsync<DateTime>(r.Schema.DataFields[0], col0);
+        await rgr.ReadAsync<DateOnly>(r.Schema.DataFields[0], col0);
         await rgr.ReadAsync<DateTime>(r.Schema.DataFields[1], col1);
 
-        DateTime? o0 = col0[0];
-        DateTime? o1 = col0[1];
+        DateOnly? o0 = col0[0];
+        DateOnly? o1 = col0[1];
 
-        Assert.Equal(new DateTime(2017, 1, 1), o0);
-        Assert.Equal(new DateTime(2017, 2, 1), o1);
+        Assert.Equal(new DateOnly(2017, 1, 1), o0);
+        Assert.Equal(new DateOnly(2017, 2, 1), o1);
     }
 
     [Theory]

src/Parquet.Test/StatisticsTest.cs

@@ -69,7 +69,6 @@ public async Task Issue735() {
 
         var parquetOptions = new ParquetOptions {
             UseBigDecimal = false,
-            UseDateOnlyTypeForDates = true,
             UseTimeOnlyTypeForTimeMillis = true,
             MaximumSmallPoolFreeBytes = 32 * 1024 * 1024,
             MaximumLargePoolFreeBytes = 64 * 1024 * 1024,

src/Parquet.Test/Types/EndToEndTypeTest.cs

@@ -405,8 +405,7 @@ public async Task Type_date_writes_and_reads() {
     public async Task Type_dateonly_writes_and_reads() {
         var field = new DataField<DateOnly>("dateOnly");
         DateOnly expected = DateOnly.FromDateTime(DateTime.UtcNow);
-        var options = new ParquetOptions { UseDateOnlyTypeForDates = true };
-        DateOnly actual = await WriteReadSingleAsync(field, expected, options);
+        DateOnly actual = await WriteReadSingleAsync(field, expected);
         Assert.Equal(expected, actual);
     }
 

src/Parquet/Encodings/SchemaEncoder.cs

@@ -268,7 +268,7 @@ static bool TryBuildStruct(List<SchemaElement> schema,
 
         // date
         if(se.LogicalType?.DATE != null || se.ConvertedType == ConvertedType.DATE) {
-            return options.UseDateOnlyTypeForDates ? typeof(DateOnly) : typeof(DateTime);
+            return typeof(DateOnly);
         }
 
         // time

src/Parquet/ParquetOptions.cs

@@ -32,13 +32,7 @@ public class ParquetOptions {
     /// When true, big integers are always treated as dates when reading files.
     /// </summary>
     public bool TreatBigIntegersAsDates { get; set; } = true;
-
-    /// <summary>
-    /// When set to true, parquet dates will be deserialized as <see cref="DateOnly"/>, otherwise as
-    /// <see cref="DateTime"/> with missing time part.
-    /// </summary>
-    public bool UseDateOnlyTypeForDates { get; set; } = false;
-
+
     /// <summary>
     /// When set to true, parquet times with millisecond precision will be deserialized as <see cref="TimeOnly"/>,
     /// otherwise as <see cref="TimeSpan"/> with missing time part.