diff mercurial/transaction.py @ 33814:bbbbd3c30bfc

util: add base class for transactional context managers

We have at least three types with a close() and a release() method
where the close() method is supposed to be called on success and the
release() method is supposed to be called last, whether successful or
not. Two of them (transaction and dirstateguard) already have
identical implementations of __enter__ and __exit__. Let's extract a
base class for this, so we reuse the code and so the third type
(transactionmanager) can also be used as a context manager.

Differential Revision: https://phab.mercurial-scm.org/D392

--- a/mercurial/transaction.py	Mon Aug 14 16:26:36 2017 -0700
+++ b/mercurial/transaction.py	Fri Jul 28 22:42:10 2017 -0700
@@ -101,7 +101,7 @@
         # only pure backup file remains, it is sage to ignore any error
         pass
 
-class transaction(object):
+class transaction(util.transactional):
     def __init__(self, report, opener, vfsmap, journalname, undoname=None,
                  after=None, createmode=None, validator=None, releasefn=None,
                  checkambigfiles=None):
@@ -376,16 +376,6 @@
         if self.count > 0 and self.usages == 0:
             self._abort()
 
-    def __enter__(self):
-        return self
-
-    def __exit__(self, exc_type, exc_val, exc_tb):
-        try:
-            if exc_type is None:
-                self.close()
-        finally:
-            self.release()
-
     def running(self):
         return self.count > 0