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.
#!/bin/sh
hg init
echo a > a
hg add a
hg commit -m "test" -d "0 0"
hg history
hg tag -d "0 0" "bleah"
hg history
echo foo >> .hgtags
hg tag -d "0 0" "bleah2" || echo "failed"
hg tag -d "0 0" -r 0 "bleah2" 1 || echo "failed"
hg revert .hgtags
hg tag -d "0 0" -r 0 "bleah0"
hg tag -l -d "0 0" "bleah1" 1
cat .hgtags
cat .hg/localtags
hg tag -l 'xx
newline'
hg tag -l 'xx:xx'
true