# HG changeset patch
# User Bryan O'Sullivan <bryano@fb.com>
# Date 2016-01-15 21:14:45
# Node ID 054abf2377e806d9ba51130dd3f9db2670d8bdf5
# Parent  f7f3958d39c037be5f3a13e8037aebd481c15c50

lock: turn a lock into a Python context manager

This lets us greatly simply acquire/release cycles.

Code pattern before:

  try:
    lock = repo.lock()
    # zillions of lines of code
  finally:
    lock.release()

And after:

  with repo.lock():
    # ...

diff --git a/mercurial/lock.py b/mercurial/lock.py
--- a/mercurial/lock.py
+++ b/mercurial/lock.py
@@ -58,6 +58,12 @@ class lock(object):
         if self.acquirefn:
             self.acquirefn()
 
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc_value, exc_tb):
+        self.release()
+
     def __del__(self):
         if self.held:
             warnings.warn("use lock.release instead of del lock",