Fix date parsing for XLS and ODS files to avoid timezone-dependency. (#3825)

Closes #3740.

main/src/com/google/refine/importers/OdsImporter.java

@@ -40,9 +40,12 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.Serializable;
 import java.util.ArrayList;
+import java.util.Calendar;
+import java.util.Date;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.TimeZone;
 
 import org.odftoolkit.odfdom.doc.OdfDocument;
 import org.odftoolkit.odfdom.doc.table.OdfTable;

main/src/com/google/refine/util/ParsingUtilities.java

@@ -99,6 +99,7 @@ public class ParsingUtilities {
     public static final ObjectWriter defaultWriter = mapper.writerWithView(JsonViews.NonSaveMode.class).with(defaultFilters);
 
     public static final DateTimeFormatter ISO8601 = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss'Z'");
+    private static final ZoneOffset defaultTimeOffset = OffsetDateTime.now().getOffset();
                 
     static public Properties parseUrlParameters(HttpServletRequest request) {
         Properties options = new Properties();
@@ -245,12 +246,28 @@ public class ParsingUtilities {
         return o instanceof OffsetDateTime;
     }
 
+    /**
+     * Converts an old-style Java Date to an OffsetDateTime,
+     * assuming the date is represented in the current default system timezone
+     * (which is what you get if the date was parsed using `Calendar.getDefault()`).
+     * 
+     * @param date
+     * @return
+     */
     public static OffsetDateTime toDate(Date date) {
-        return date.toInstant().atOffset(ZoneOffset.UTC);
+        return date.toInstant().atOffset(defaultTimeOffset);
     }
 
+    /**
+     * Converts an old-style Java Calendar to an OffsetDateTime,
+     * assuming the date is represented in the current default system timezone
+     * (which is what you get if the date was parsed using `Calendar.getDefault()`).
+     * 
+     * @param date
+     * @return
+     */
     public static OffsetDateTime toDate(Calendar date) {
-        return date.toInstant().atOffset(ZoneOffset.UTC);
+        return date.toInstant().atOffset(defaultTimeOffset);
     }
 
 	public static ObjectNode evaluateJsonStringToObjectNode(String optionsString) {

main/tests/server/src/com/google/refine/importers/ExcelImporterTests.java

@@ -45,6 +45,8 @@ import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.time.Month;
+import java.time.OffsetDateTime;
 import java.util.Calendar;
 import java.util.Date;
 
@@ -200,6 +202,39 @@ public class ExcelImporterTests extends ImporterTest {
         }
     }
     
+    @Test
+    public void readExcelDates() throws FileNotFoundException, IOException {
+        ArrayNode sheets = ParsingUtilities.mapper.createArrayNode();
+        sheets.add(ParsingUtilities.mapper.readTree("{name: \"file-source#Test Sheet 0\", fileNameAndSheetIndex: \"file-source#0\", rows: 31, selected: true}"));
+        whenGetArrayOption("sheets", options, sheets);
+
+        whenGetIntegerOption("ignoreLines", options, 0);
+        whenGetIntegerOption("headerLines", options, 0);
+        whenGetIntegerOption("skipDataLines", options, 0);
+        whenGetIntegerOption("limit", options, -1);
+        whenGetBooleanOption("storeBlankCellsAsNulls", options, true);
+
+        InputStream stream = ClassLoader.getSystemResourceAsStream("dates.xls");
+
+        parseOneFile(SUT, stream);
+        
+        // The original value reads 2021-04-18 in the Excel file.
+        // We make sure it is not shifted by a day because of timezone handling
+        Object cellValue = project.rows.get(0).getCellValue(0);
+        Assert.assertTrue(cellValue instanceof OffsetDateTime);
+        OffsetDateTime date = (OffsetDateTime) cellValue;
+        Assert.assertEquals(date.getYear(), 2021);
+        Assert.assertEquals(date.getMonth(), Month.APRIL);
+        Assert.assertEquals(date.getDayOfMonth(), 18);
+        // Same, with January 1st (in winter / no DST)
+        Object cellValue2 = project.rows.get(1).getCellValue(0);
+        Assert.assertTrue(cellValue instanceof OffsetDateTime);
+        OffsetDateTime date2 = (OffsetDateTime) cellValue2;
+        Assert.assertEquals(date2.getYear(), 2021);
+        Assert.assertEquals(date2.getMonth(), Month.JANUARY);
+        Assert.assertEquals(date2.getDayOfMonth(), 1);
+    }
+
     @Test
     public void readMultiSheetXls() throws FileNotFoundException, IOException{