ARROW-17627: [Go][Parquet] Forward schema metadata to file without StoreSchema

go/parquet/pqarrow/file_reader_test.go

@@ -191,3 +191,28 @@ func TestRecordReaderSerial(t *testing.T) {
 	assert.Same(t, io.EOF, err)
 	assert.Nil(t, rec)
 }
+
+func TestFileReaderWriterMetadata(t *testing.T) {
+	mem := memory.NewCheckedAllocator(memory.DefaultAllocator)
+	defer mem.AssertSize(t, 0)
+
+	tbl := makeDateTimeTypesTable(mem, true, true)
+	defer tbl.Release()
+
+	meta := arrow.NewMetadata([]string{"foo", "bar"}, []string{"bar", "baz"})
+	sc := arrow.NewSchema(tbl.Schema().Fields(), &meta)
+
+	var buf bytes.Buffer
+	writer, err := pqarrow.NewFileWriter(sc, &buf, nil, pqarrow.NewArrowWriterProperties(pqarrow.WithAllocator(mem)))
+	require.NoError(t, err)
+	require.NoError(t, writer.WriteTable(tbl, tbl.NumRows()))
+	require.NoError(t, writer.Close())
+
+	pf, err := file.NewParquetReader(bytes.NewReader(buf.Bytes()), file.WithReadProps(parquet.NewReaderProperties(mem)))
+	require.NoError(t, err)
+	defer pf.Close()
+
+	kvMeta := pf.MetaData().KeyValueMetadata()
+	assert.Equal(t, []string{"foo", "bar"}, kvMeta.Keys())
+	assert.Equal(t, []string{"bar", "baz"}, kvMeta.Values())
+}

go/parquet/pqarrow/file_writer.go

@@ -73,11 +73,11 @@ func NewFileWriter(arrschema *arrow.Schema, w io.Writer, props *parquet.WriterPr
 	}
 
 	meta := make(metadata.KeyValueMetadata, 0)
-	if arrprops.storeSchema {
-		for i := 0; i < arrschema.Metadata().Len(); i++ {
-			meta.Append(arrschema.Metadata().Keys()[i], arrschema.Metadata().Values()[i])
-		}
+	for i := 0; i < arrschema.Metadata().Len(); i++ {
+		meta.Append(arrschema.Metadata().Keys()[i], arrschema.Metadata().Values()[i])
+	}
 
+	if arrprops.storeSchema {
 		serializedSchema := flight.SerializeSchema(arrschema, props.Allocator())
 		meta.Append("ARROW:schema", base64.StdEncoding.EncodeToString(serializedSchema))
 	}