Fix MonthDay add/subtract around Feb29 [3528941]

JodaOrg · May 23, 2012 · 2ea8563 · 2ea8563
1 parent cc3262f
commit 2ea8563
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diff --git a/RELEASE-NOTES.txt b/RELEASE-NOTES.txt
@@ -45,6 +45,11 @@ None
 
 Bug fixes since 2.1
 -------------------
+- MonthDay add/subtract [3528941]
+  Addition and subtraction in MonthDay was fixed.
+  It previously didn't work when the start value was 29th February.
+
+
 - DateTimeFormatter.parseInto() [3522138]
   The v2.0 changes to handle parsing of month/day on their own (for Feb 29th) cause
   parseInto() to lose the year. This fix reverts behaviour to v1.x so that parseInto()

diff --git a/src/main/java/org/joda/time/chrono/BasicMonthOfYearDateTimeField.java b/src/main/java/org/joda/time/chrono/BasicMonthOfYearDateTimeField.java
@@ -206,6 +206,12 @@ public int[] add(ReadablePartial partial, int fieldIndex, int[] values, int valu
         if (valueToAdd == 0) {
             return values;
         }
+        if (partial.size() > 0 && partial.getFieldType(0).equals(DateTimeFieldType.monthOfYear()) && fieldIndex == 0) {
+            // month is largest field and being added to, such as month-day
+            int curMonth0 = partial.getValue(0) - 1;
+            int newMonth = ((curMonth0 + (valueToAdd % 12) + 12) % 12) + 1;
+            return set(partial, 0, values, newMonth);
+        }
         if (DateTimeUtils.isContiguous(partial)) {
             long instant = 0L;
             for (int i = 0, isize = partial.size(); i < isize; i++) {

diff --git a/src/test/java/org/joda/time/TestMonthDay_Basics.java b/src/test/java/org/joda/time/TestMonthDay_Basics.java
@@ -448,6 +448,34 @@ public void testPlusMonths_int() {
         assertEquals(expected, result);
     }
 
+    public void testPlusMonths_int_fromLeap() {
+        MonthDay test = new MonthDay(2, 29, ISOChronology.getInstanceUTC());
+        MonthDay result = test.plusMonths(1);
+        MonthDay expected = new MonthDay(3, 29, ISOChronology.getInstance());
+        assertEquals(expected, result);
+    }
+
+    public void testPlusMonths_int_negativeFromLeap() {
+        MonthDay test = new MonthDay(2, 29, ISOChronology.getInstanceUTC());
+        MonthDay result = test.plusMonths(-1);
+        MonthDay expected = new MonthDay(1, 29, ISOChronology.getInstance());
+        assertEquals(expected, result);
+    }
+
+    public void testPlusMonths_int_endOfMonthAdjust() {
+        MonthDay test = new MonthDay(3, 31, ISOChronology.getInstanceUTC());
+        MonthDay result = test.plusMonths(1);
+        MonthDay expected = new MonthDay(4, 30, ISOChronology.getInstance());
+        assertEquals(expected, result);
+    }
+
+    public void testPlusMonths_int_negativeEndOfMonthAdjust() {
+        MonthDay test = new MonthDay(3, 31, ISOChronology.getInstanceUTC());
+        MonthDay result = test.plusMonths(-1);
+        MonthDay expected = new MonthDay(2, 29, ISOChronology.getInstance());
+        assertEquals(expected, result);
+    }
+
     public void testPlusMonths_int_same() {
         MonthDay test = new MonthDay(6, 5, ISO_UTC);
         MonthDay result = test.plusMonths(0);
@@ -468,13 +496,28 @@ public void testPlusMonths_int_adjust() {
         assertEquals(expected, result);
     }
 
+    //-------------------------------------------------------------------------
     public void testPlusDays_int() {
         MonthDay test = new MonthDay(5, 10, BuddhistChronology.getInstance());
         MonthDay result = test.plusDays(1);
         MonthDay expected = new MonthDay(5, 11, BuddhistChronology.getInstance());
         assertEquals(expected, result);
     }
 
+    public void testPlusDays_int_fromLeap() {
+        MonthDay test = new MonthDay(2, 29, ISOChronology.getInstanceUTC());
+        MonthDay result = test.plusDays(1);
+        MonthDay expected = new MonthDay(3, 1, ISOChronology.getInstance());
+        assertEquals(expected, result);
+    }
+
+    public void testPlusDays_int_negativeFromLeap() {
+        MonthDay test = new MonthDay(2, 29, ISOChronology.getInstanceUTC());
+        MonthDay result = test.plusDays(-1);
+        MonthDay expected = new MonthDay(2, 28, ISOChronology.getInstance());
+        assertEquals(expected, result);
+    }
+
     public void testPlusDays_same() {
         MonthDay test = new MonthDay(5, 10, BuddhistChronology.getInstance());
         MonthDay result = test.plusDays(0);
@@ -499,6 +542,34 @@ public void testMinusMonths_int() {
         assertEquals(expected, result);
     }
 
+    public void testMinusMonths_int_fromLeap() {
+        MonthDay test = new MonthDay(2, 29, ISOChronology.getInstanceUTC());
+        MonthDay result = test.minusMonths(1);
+        MonthDay expected = new MonthDay(1, 29, ISOChronology.getInstance());
+        assertEquals(expected, result);
+    }
+
+    public void testMinusMonths_int_negativeFromLeap() {
+        MonthDay test = new MonthDay(2, 29, ISOChronology.getInstanceUTC());
+        MonthDay result = test.minusMonths(-1);
+        MonthDay expected = new MonthDay(3, 29, ISOChronology.getInstance());
+        assertEquals(expected, result);
+    }
+
+    public void testMinusMonths_int_endOfMonthAdjust() {
+        MonthDay test = new MonthDay(3, 31, ISOChronology.getInstanceUTC());
+        MonthDay result = test.minusMonths(1);
+        MonthDay expected = new MonthDay(2, 29, ISOChronology.getInstance());
+        assertEquals(expected, result);
+    }
+
+    public void testMinusMonths_int_negativeEndOfMonthAdjust() {
+        MonthDay test = new MonthDay(3, 31, ISOChronology.getInstanceUTC());
+        MonthDay result = test.minusMonths(-1);
+        MonthDay expected = new MonthDay(4, 30, ISOChronology.getInstance());
+        assertEquals(expected, result);
+    }
+
     public void testMinusMonths_int_same() {
         MonthDay test = new MonthDay(6, 5, ISO_UTC);
         MonthDay result = test.minusMonths(0);
@@ -519,13 +590,28 @@ public void testMinusMonths_int_adjust() {
         assertEquals(expected, result);
     }
 
+    //-------------------------------------------------------------------------
     public void testMinusDays_int() {
         MonthDay test = new MonthDay(5, 11, BuddhistChronology.getInstance());
         MonthDay result = test.minusDays(1);
         MonthDay expected = new MonthDay(5, 10, BuddhistChronology.getInstance());
         assertEquals(expected, result);
     }
 
+    public void testMinusDays_int_fromLeap() {
+        MonthDay test = new MonthDay(2, 29, ISOChronology.getInstanceUTC());
+        MonthDay result = test.minusDays(1);
+        MonthDay expected = new MonthDay(2, 28, ISOChronology.getInstance());
+        assertEquals(expected, result);
+    }
+
+    public void testMinusDays_int_negativeFromLeap() {
+        MonthDay test = new MonthDay(2, 29, ISOChronology.getInstanceUTC());
+        MonthDay result = test.minusDays(-1);
+        MonthDay expected = new MonthDay(3, 1, ISOChronology.getInstance());
+        assertEquals(expected, result);
+    }
+
     public void testMinusDays_same() {
         MonthDay test = new MonthDay(5, 11, BuddhistChronology.getInstance());
         MonthDay result = test.minusDays(0);