Fix #19 attempts didn't stop on success

Uses fix from https://github.com/zopefoundation/transaction/pull/20/files
but different test changes.

docs/convenience.rst

@@ -125,7 +125,7 @@ Of course, other errors are propagated directly:
     >>> for attempt in transaction.manager.attempts():
     ...     with attempt:
     ...         ntry += 1
-    ...         if ntry == 3:
+    ...         if ntry % 3:
     ...             raise ValueError(ntry)
     Traceback (most recent call last):
     ...
@@ -135,6 +135,7 @@ We can use the default transaction manager:
 
 .. doctest::
 
+    >>> ntry = 0
     >>> for attempt in transaction.attempts():
     ...     with attempt as t:
     ...         t.note('test')
@@ -143,9 +144,9 @@ We can use the default transaction manager:
     ...         dm['ntry'] = ntry
     ...         if ntry % 3:
     ...             raise Retry(ntry)
-    3 3
-    3 4
-    3 5
+    3 0
+    3 1
+    3 2
 
 Sometimes, a data manager doesn't raise exceptions directly, but
 wraps other other systems that raise exceptions outside of it's
@@ -172,9 +173,9 @@ attempted again.
     ...         dm2['ntry'] = ntry
     ...         if ntry % 3:
     ...             raise ValueError('we really should retry this')
-    6 0
-    6 1
-    6 2
+    3 0
+    3 1
+    3 2
 
     >>> dm2['ntry']
     3

transaction/_manager.py

@@ -144,7 +144,10 @@ class TransactionManager(object):
         while number:
             number -= 1
             if number:
-                yield Attempt(self)
+                attempt = Attempt(self)
+                yield attempt
+                if attempt.sucess:
+                    break
             else:
                 yield self
 
@@ -167,6 +170,8 @@ class ThreadTransactionManager(TransactionManager, threading.local):
 
 class Attempt(object):
 
+    sucess = False
+
     def __init__(self, manager):
         self.manager = manager
 
@@ -186,5 +191,7 @@ class Attempt(object):
                 self.manager.commit()
             except:
                 return self._retry_or_raise(*sys.exc_info())
+            else:
+                self.sucess = True
         else:
             return self._retry_or_raise(t, v, tb)

transaction/tests/test__manager.py

@@ -236,6 +236,16 @@ class TransactionManagerTests(unittest.TestCase):
         self.assertEqual(len(found), 1)
         self.assertTrue(found[0] is tm)
 
+    def test_attempts_stop_on_success(self):
+        tm = self._makeOne()
+
+        i = 0
+        for attempt in tm.attempts():
+            with attempt:
+                i += 1
+
+        self.assertEqual(i, 1)
+
     def test_attempts_w_default_count(self):
         from transaction._manager import Attempt
         tm = self._makeOne()