issue when formatting number when divisor is needed (#895)

* reproduce issue 69812

* workaround for issue

poi-ooxml/src/test/java/org/apache/poi/xssf/usermodel/TestXSSFBugs.java

@@ -3938,6 +3938,20 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
         }
     }
 
+    @Test
+    void testBug69812() throws Exception {
+        try (XSSFWorkbook wb = openSampleWorkbook("bug69812.xlsx")) {
+            XSSFSheet sheet = wb.getSheetAt(0);
+            XSSFRow row = sheet.getRow(0);
+            XSSFCell cellA1 = row.getCell(0);
+            DataFormatter dataFormatter = new DataFormatter();
+            String cellValue = dataFormatter.formatCellValue(cellA1);
+            // https://bz.apache.org/bugzilla/show_bug.cgi?id=69812: user says this should be "25,386"
+            assertEquals("25,396", cellValue);
+            assertEquals("#,##0,,", cellA1.getCellStyle().getDataFormatString());
+        }
+    }
+
     private static void readByCommonsCompress(File temp_excel_poi) throws IOException {
         /* read by commons-compress*/
         try (ZipFile zipFile = ZipFile.builder().setFile(temp_excel_poi).get()) {

poi/src/main/java/org/apache/poi/ss/usermodel/DataFormatter.java

@@ -808,6 +808,10 @@ public class DataFormatter {
             }
         }
 
+        boolean requiresScaling() {
+            return divider != null;
+        }
+
         private Object scaleInput(Object obj) {
             if (divider != null) {
                 if (obj instanceof BigDecimal) {
@@ -965,12 +969,22 @@ public class DataFormatter {
         if (numberFormat == null) {
             return Double.toString(d);
         }
-        String formatted;
-        try {
-            //see https://github.com/apache/poi/pull/321 -- but this sometimes fails, thus the catch and retry
-            formatted = numberFormat.format(BigDecimal.valueOf(d));
-        } catch (NumberFormatException nfe) {
-            formatted = numberFormat.format(d);
+        String formatted = null;
+        if (numberFormat instanceof InternalDecimalFormatWithScale) {
+            InternalDecimalFormatWithScale idfws = (InternalDecimalFormatWithScale) numberFormat;
+            if (idfws.requiresScaling()) {
+                // hack for https://bz.apache.org/bugzilla/show_bug.cgi?id=69812
+                // the https://github.com/apache/poi/pull/321 hack causes problems here
+                formatted = idfws.format(d);
+            }
+        }
+        if (formatted == null) {
+            try {
+                //see https://github.com/apache/poi/pull/321 -- but this sometimes fails, thus the catch and retry
+                formatted = numberFormat.format(BigDecimal.valueOf(d));
+            } catch (NumberFormatException nfe) {
+                formatted = numberFormat.format(d);
+            }
         }
         return formatted.replaceFirst("E(\\d)", "E+$1"); // to match Excel's E-notation
     }