add prechangegroup and pretxnchangegroup hooks.
prechangegroup lets you stop push, pull or unbundle before it begins.
pretxnchangegroup lets you inspect changegroup before transaction is
committed, and roll back if you not like it.
# HG changeset patch
# User test
# Node ID b51ca55c20354097ca299529d18b5cd356976ba2
# Parent 0000000000000000000000000000000000000000
1
diff -r 000000000000 -r b51ca55c2035 foo
--- /dev/null Thu Jan 1 00:00:00 1970 +0000
+++ b/foo Thu Jan 1 00:00:00 1970 +0000
@@ -0,0 +1,1 @@
+a
# HG changeset patch
# User test
# Node ID 451c12a24e5a7336921b8d93e280837d7c2b4fc1
# Parent b51ca55c20354097ca299529d18b5cd356976ba2
2
diff -r b51ca55c2035 -r 451c12a24e5a foo
--- a/foo Thu Jan 1 00:00:00 1970 +0000
+++ /dev/null Thu Jan 1 00:00:00 1970 +0000
@@ -1,1 +0,0 @@
-a
changeset: 0:b51ca55c2035
user: test
date: Thu Jan 1 00:00:00 1970 +0000
summary: 1
diff -r 000000000000 -r b51ca55c2035 foo
--- /dev/null Thu Jan 1 00:00:00 1970 +0000
+++ b/foo Thu Jan 1 00:00:00 1970 +0000
@@ -0,0 +1,1 @@
+a
changeset: 1:451c12a24e5a
tag: tip
user: test
date: Thu Jan 1 00:00:00 1970 +0000
summary: 2
diff -r b51ca55c2035 -r 451c12a24e5a foo
--- a/foo Thu Jan 1 00:00:00 1970 +0000
+++ /dev/null Thu Jan 1 00:00:00 1970 +0000
@@ -1,1 +0,0 @@
-a