Allow Timestamp comparisons against out-of-range values

Prior to the related change, clients may have written down X-Delete-At headers
that are outside of the Timestamp range, for example.

Change-Id: Ib8ae7ebcbdb32e0aa58446bd1ef949e5e2f63e74
Related-Change: I23666ec8a067d829eaf9bfe54bd086c320b3429e
Related-Bug: 1821204
Partial-Bug: 1860149

swift/common/utils.py

@@ -1231,7 +1231,7 @@ class Timestamp(object):
     compatible for normalized timestamps which do not include an offset.
     """
 
-    def __init__(self, timestamp, offset=0, delta=0):
+    def __init__(self, timestamp, offset=0, delta=0, check_bounds=True):
         """
         Create a new Timestamp.
 
@@ -1275,10 +1275,11 @@ class Timestamp(object):
                 raise ValueError(
                     'delta must be greater than %d' % (-1 * self.raw))
             self.timestamp = float(self.raw * PRECISION)
-        if self.timestamp < 0:
-            raise ValueError('timestamp cannot be negative')
-        if self.timestamp >= 10000000000:
-            raise ValueError('timestamp too large')
+        if check_bounds:
+            if self.timestamp < 0:
+                raise ValueError('timestamp cannot be negative')
+            if self.timestamp >= 10000000000:
+                raise ValueError('timestamp too large')
 
     @classmethod
     def now(cls, offset=0, delta=0):
@@ -1352,21 +1353,24 @@ class Timestamp(object):
         if other is None:
             return False
         if not isinstance(other, Timestamp):
-            other = Timestamp(other)
+            try:
+                other = Timestamp(other, check_bounds=False)
+            except ValueError:
+                return False
         return self.internal == other.internal
 
     def __ne__(self, other):
-        if other is None:
-            return True
-        if not isinstance(other, Timestamp):
-            other = Timestamp(other)
-        return self.internal != other.internal
+        return not (self == other)
 
     def __lt__(self, other):
         if other is None:
             return False
         if not isinstance(other, Timestamp):
-            other = Timestamp(other)
+            other = Timestamp(other, check_bounds=False)
+        if other.timestamp < 0:
+            return False
+        if other.timestamp >= 10000000000:
+            return True
         return self.internal < other.internal
 
     def __hash__(self):

test/unit/common/test_utils.py

@@ -858,6 +858,37 @@ class TestTimestamp(unittest.TestCase):
         self.assertIn(ts_0, d)  # sanity
         self.assertIn(ts_0_also, d)
 
+    def test_out_of_range_comparisons(self):
+        now = utils.Timestamp.now()
+
+        def check_is_later(val):
+            self.assertTrue(now != val)
+            self.assertFalse(now == val)
+            self.assertTrue(now <= val)
+            self.assertTrue(now < val)
+            self.assertTrue(val > now)
+            self.assertTrue(val >= now)
+
+        check_is_later(1e30)
+        check_is_later(1579753284000)  # someone gave us ms instead of s!
+        check_is_later('1579753284000')
+        check_is_later(b'1e15')
+        check_is_later(u'1.e+10_f')
+
+        def check_is_earlier(val):
+            self.assertTrue(now != val)
+            self.assertFalse(now == val)
+            self.assertTrue(now >= val)
+            self.assertTrue(now > val)
+            self.assertTrue(val < now)
+            self.assertTrue(val <= now)
+
+        check_is_earlier(-1)
+        check_is_earlier(-0.1)
+        check_is_earlier('-9999999')
+        check_is_earlier(b'-9999.999')
+        check_is_earlier(u'-1234_5678')
+
 
 class TestTimestampEncoding(unittest.TestCase):