# HG changeset patch
# User Martin von Zweigbergk <martinvonz@google.com>
# Date 2017-07-12 20:57:03
# Node ID fad6852cf87944f7405bb2cf18fc47424465f61d
# Parent  0491004e2233c2c33c300698b1e1855a79be9874

histedit: extract InterventionRequired transaction handling to utils

rebase will have similar logic, so let's extract it. Besides, it makes
the histedit code more readable.

We may want to parametrize acceptintervention() by the exception(s)
that should result in transaction close.

Differential Revision: https://phab.mercurial-scm.org/D66

diff --git a/hgext/histedit.py b/hgext/histedit.py
--- a/hgext/histedit.py
+++ b/hgext/histedit.py
@@ -1122,7 +1122,7 @@ def _continuehistedit(ui, repo, state):
         # and reopen a transaction. For example, if the action executes an
         # external process it may choose to commit the transaction first.
         tr = repo.transaction('histedit')
-    try:
+    with util.acceptintervention(tr):
         while state.actions:
             state.write(tr=tr)
             actobj = state.actions[0]
@@ -1136,17 +1136,6 @@ def _continuehistedit(ui, repo, state):
             state.replacements.extend(replacement_)
             state.actions.pop(0)
 
-        if tr is not None:
-            tr.close()
-    except error.InterventionRequired:
-        if tr is not None:
-            tr.close()
-        raise
-    except Exception:
-        if tr is not None:
-            tr.abort()
-        raise
-
     state.write()
     ui.progress(_("editing"), None)
 
diff --git a/mercurial/util.py b/mercurial/util.py
--- a/mercurial/util.py
+++ b/mercurial/util.py
@@ -19,6 +19,7 @@ import bz2
 import calendar
 import codecs
 import collections
+import contextlib
 import datetime
 import errno
 import gc
@@ -589,6 +590,24 @@ class sortdict(collections.OrderedDict):
             del self[key]
         super(sortdict, self).__setitem__(key, value)
 
+@contextlib.contextmanager
+def acceptintervention(tr=None):
+    """A context manager that closes the transaction on InterventionRequired
+
+    If no transaction was provided, this simply runs the body and returns
+    """
+    if not tr:
+        yield
+        return
+    try:
+        yield
+        tr.close()
+    except error.InterventionRequired:
+        tr.close()
+        raise
+    finally:
+        tr.release()
+
 class _lrucachenode(object):
     """A node in a doubly linked list.