tests/test-pending.t

log: add -L/--line-range option to follow file history by line range

We add an experimental -L/--line-range option to 'hg log' taking file patterns
along with a line range using the (new) FILE,FROMLINE-TOLINE syntax where FILE
may be a pattern (matching exactly one file). The resulting history is similar
to what the "followlines" revset except that, if --patch is specified,
only diff hunks within specified line range are shown.

Basically, this brings the CLI on par with what currently only exists in hgweb
through line selection in "file" and "annotate" views resulting in a file log
with filtered patch to only display followed line range.

The option may be specified multiple times and can be combined with --rev and
regular file patterns to further restrict revisions. Usage of this option
requires --follow; revisions are shown in descending order and renames are
followed. Only the --graph option is currently not supported.

The UI is the result of a consensus from review feedback at:

  https://www.mercurial-scm.org/pipermail/mercurial-devel/2017-October/106749.html


The implementation spreads between commands.log() and cmdutil module.
In commands.log(), the main loop may now use a "hunksfilter" factory (similar
to "filematcher") that, for a given "rev", produces a filtering function
for diff hunks for a given file context object.
The logic to build revisions from -L/--line-range options lives in
cmdutil.getloglinerangerevs() which produces "revs", "filematcher" and
"hunksfilter" information. Revisions obtained by following files' line range
are filtered if they do not match the revset specified by --rev option. If
regular FILE arguments are passed along with -L options, both filematchers are
combined into a new matcher.

.. feature::

   Add an experimental -L/--line-range FILE,FROMLINE-TOLINE option to 'hg log'
   command to follow the history of files by line range. In combination with
   -p/--patch option, only diff hunks within specified line range will be
   displayed. Feedback, especially on UX aspects, is welcome.

Verify that pending changesets are seen by pretxn* hooks but not by other
processes that access the destination repo while the hooks are running.

The hooks (python and external) both reject changesets after some think time,
during which another process runs pull.  Each hook creates a file ('notify') to
indicate to the controlling process that it is running; the process removes the
file to indicate the hook can terminate.

init env vars

  $ d=`pwd`
  $ maxwait=20

utility to run the test - start a push in the background and run pull

  $ dotest() {
  >     rm -f notify
  >     printf 'push '; hg -R child-push tip --template '{node}\n'
  >     hg -R child-push -q push > push.out 2>&1 &
  > 
  >     # wait for hook to create the notify file
  >     i=$maxwait
  >     while [ ! -f notify -a $i != 0 ]; do
  >         sleep 1
  >         i=`expr $i - 1`
  >     done
  > 
  >     # run pull
  >     hg -R child-pull -q pull
  >     rc=$?
  > 
  >     # tell hook to finish; notify should exist.
  >     rm notify
  >     wait
  > 
  >     cat push.out
  >     printf 'pull '; hg -R child-pull tip --template '{node}\n'
  >     return $rc
  > }

python hook

  $ cat <<EOF > reject.py
  > import os, time
  > from mercurial import ui, localrepo
  > def rejecthook(ui, repo, hooktype, node, **opts):
  >     ui.write('hook %s\\n' % repo['tip'].hex())
  >     # create the notify file so caller knows we're running
  >     fpath = os.path.join('$d', 'notify')
  >     f = open(fpath, 'w')
  >     f.close()
  >     # wait for ack - caller should delete the notify file
  >     i = $maxwait
  >     while os.path.exists(fpath) and i > 0:
  >         time.sleep(1)
  >         i -= 1
  >     return True # reject the changesets
  > EOF

external hook

  $ cat <<EOF > reject.sh
  > printf 'hook '; hg tip --template '{node}\\n'
  > # create the notify file so caller knows we're running
  > fpath=$d/notify
  > touch \$fpath
  > # wait for ack - caller should delete the notify file
  > i=$maxwait
  > while [ -f \$fpath -a \$i != 0 ]; do
  >     sleep 1
  >     i=\`expr \$i - 1\`
  > done
  > exit 1 # reject the changesets
  > EOF

create repos

  $ hg init parent
  $ hg clone -q parent child-push
  $ hg clone -q parent child-pull
  $ echo a > child-push/a
  $ hg -R child-push add child-push/a
  $ hg -R child-push commit -m a -d '1000000 0'

test python hook

  $ cat <<EOF > parent/.hg/hgrc
  > [extensions]
  > reject = $d/reject.py
  > [hooks]
  > pretxnchangegroup = python:reject.rejecthook
  > EOF

  $ dotest
  push 29b62aeb769fdf78d8d9c5f28b017f76d7ef824b
  hook 29b62aeb769fdf78d8d9c5f28b017f76d7ef824b
  transaction abort!
  rollback completed
  abort: pretxnchangegroup hook failed
  pull 0000000000000000000000000000000000000000

test external hook

  $ cat <<EOF > parent/.hg/hgrc
  > [hooks]
  > pretxnchangegroup = sh $d/reject.sh
  > EOF

  $ dotest
  push 29b62aeb769fdf78d8d9c5f28b017f76d7ef824b
  hook 29b62aeb769fdf78d8d9c5f28b017f76d7ef824b
  transaction abort!
  rollback completed
  abort: pretxnchangegroup hook exited with status 1
  pull 0000000000000000000000000000000000000000

Test that pending on transaction without changegroup see the normal changegroup(
(issue4609)

  $ cat <<EOF > parent/.hg/hgrc
  > [hooks]
  > pretxnchangegroup=
  > pretxnclose = hg tip -T "tip: {node|short}\n"
  > [phases]
  > publishing=False
  > EOF

setup

  $ cd parent
  $ echo a > a
  $ hg add a
  $ hg commit -m a
  tip: cb9a9f314b8b

actual test

  $ hg phase --public .
  tip: cb9a9f314b8b