Tests and Python implementation.

persistent/persistence.py

@@ -11,7 +11,7 @@
 # FOR A PARTICULAR PURPOSE.
 #
 ##############################################################################
-import sys
+
 
 from zope.interface import implementer
 
@@ -20,14 +20,13 @@
 from persistent.interfaces import UPTODATE
 from persistent.interfaces import CHANGED
 from persistent.interfaces import STICKY
-from persistent.interfaces import OID_TYPE
+
 from persistent.interfaces import SERIAL_TYPE
 from persistent.timestamp import TimeStamp
 from persistent.timestamp import _ZERO
 from persistent._compat import copy_reg
 from persistent._compat import intern
 
-from . import ring
 
 _INITIAL_SERIAL = _ZERO
 
@@ -558,6 +557,31 @@ def _p_is_in_cache(self, jar=None):
         if cache is not None:
             return cache.get(oid) is self
 
+    def __repr__(self):
+        oid = _OGA(self, '_Persistent__oid')
+        jar = _OGA(self, '_Persistent__jar')
+
+        oid_str = ''
+        jar_str = ''
+
+        if oid is not None:
+            try:
+                oid_str = ' oid %r' % (oid,)
+            except Exception as e:
+                oid_str = ' oid %r' % (e,)
+
+        if jar is not None:
+            try:
+                jar_str = ' in %r' % (jar,)
+            except Exception as e:
+                jar_str = ' in %r' % (e,)
+
+        return '<%s.%s object at 0x%x%s%s>' % (
+            type(self).__module__, type(self).__name__, id(self),
+            oid_str, jar_str
+        )
+
+
 def _estimated_size_in_24_bits(value):
     if value > 1073741696:
         return 16777215

persistent/tests/test_persistence.py

@@ -13,6 +13,7 @@
 ##############################################################################
 
 import platform
+import re
 import sys
 import unittest
 
@@ -1670,7 +1671,7 @@ class TestPersistent(self._getTargetClass()):
         self.assertEqual(candidate._p_state, UPTODATE)
         cache.new_ghost(KEY, candidate)
 
-        self.assertTrue(cache.get(KEY) is candidate)
+        self.assertIs(cache.get(KEY), candidate)
         self.assertEqual(candidate._p_oid, KEY)
         self.assertEqual(candidate._p_state, GHOST)
         self.assertEqual(candidate.set_by_new, 1)
@@ -1691,11 +1692,118 @@ class TestPersistent(self._getTargetClass()):
         self.assertEqual(candidate._p_state, UPTODATE)
         cache.new_ghost(KEY, candidate)
 
-        self.assertTrue(cache.get(KEY) is candidate)
+        self.assertIs(cache.get(KEY), candidate)
         self.assertEqual(candidate._p_oid, KEY)
         self.assertEqual(candidate._p_state, GHOST)
         self.assertEqual(candidate.set_by_new, 1)
 
+    def _normalize_repr(self, r):
+        # Pure-python vs C
+        r = r.replace('persistent.persistence.Persistent', 'persistent.Persistent')
+        # addresses
+        r = re.sub(r'0x[0-9a-fA-F]*', '0xdeadbeef', r)
+        # Python 3.7 removed the trailing , in exception reprs
+        r = r.replace("',)", "')")
+        # Python 2 doesn't have a leading b prefix for byte literals
+        r = r.replace("oid '", "oid b'")
+        return r
+
+    def _normalized_repr(self, o):
+        return self._normalize_repr(repr(o))
+
+    def test_repr_no_oid_no_jar(self):
+        p = self._makeOne()
+        result = self._normalized_repr(p)
+        self.assertEqual(result, '<persistent.Persistent object at 0xdeadbeef>')
+
+    def test_repr_no_oid_in_jar(self):
+        p = self._makeOne()
+
+        class Jar(object):
+            def __repr__(self):
+                return '<SomeJar>'
+
+        p._p_jar = Jar()
+
+        result = self._normalized_repr(p)
+        self.assertEqual(
+            result,
+            "<persistent.Persistent object at 0xdeadbeef in <SomeJar>>")
+
+    def test_repr_oid_no_jar(self):
+        p = self._makeOne()
+        p._p_oid = b'12345678'
+
+        result = self._normalized_repr(p)
+        self.assertEqual(
+            result,
+            "<persistent.Persistent object at 0xdeadbeef oid b'12345678'>")
+
+    def test_repr_no_oid_repr_jar_raises_exception(self):
+        p = self._makeOne()
+
+        class Jar(object):
+            def __repr__(self):
+                raise Exception('jar repr failed')
+
+        p._p_jar = Jar()
+
+        result = self._normalized_repr(p)
+        self.assertEqual(
+            result,
+            "<persistent.Persistent object at 0xdeadbeef in Exception('jar repr failed')>")
+
+
+    def test_repr_oid_raises_exception_no_jar(self):
+        p = self._makeOne()
+
+        class BadOID(bytes):
+            def __repr__(self):
+                raise Exception("oid repr failed")
+        p._p_oid = BadOID(b'12345678')
+
+        result = self._normalized_repr(p)
+        self.assertEqual(
+            result,
+            "<persistent.Persistent object at 0xdeadbeef oid Exception('oid repr failed')>")
+
+
+    def test_repr_oid_and_jar_raise_exception(self):
+        p = self._makeOne()
+
+        class BadOID(bytes):
+            def __repr__(self):
+                raise Exception("oid repr failed")
+        p._p_oid = BadOID(b'12345678')
+
+        class Jar(object):
+            def __repr__(self):
+                raise Exception('jar repr failed')
+
+        p._p_jar = Jar()
+
+
+        result = self._normalized_repr(p)
+        self.assertEqual(
+            result,
+            "<persistent.Persistent object at 0xdeadbeef oid Exception('oid repr failed')"
+            " in Exception('jar repr failed')>")
+
+
+    def test_repr_oid_and_jar(self):
+        p = self._makeOne()
+        p._p_oid = b'12345678'
+
+        class Jar(object):
+            def __repr__(self):
+                return '<SomeJar>'
+
+        p._p_jar = Jar()
+
+        result = self._normalized_repr(p)
+        self.assertEqual(result,
+                         "<persistent.Persistent object at 0xdeadbeef oid b'12345678' in <SomeJar>>")
+
 
 class PyPersistentTests(unittest.TestCase, _Persistent_Base):