$ cat >> $HGRCPATH <<EOF

  > [censor]

  > policy=ignore

  > EOF

  $ mkdir r

  $ cd r

  $ hg init

  $ echo secret > target

  $ hg commit -Am "secret"

  adding target

  $ touch bystander

  $ hg commit -Am "innocent"

  adding bystander

  $ echo erased-secret > target

  $ hg commit -m "erased secret"

  $ hg censor target --config extensions.censor= -r ".^^"

  $ hg update ".^"

  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ cat target

  $ hg update tip

  abort: file censored data/target:b1c12cf98dc8 (known-bad-output !)

  [255]